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Structural Analysis - Science topic

Structural analysis is the determination of the effects of loads on physical structures and their components. Structures subject to this type of analysis include all that must withstand loads, such as buildings, bridges, vehicles, machinery, furniture, attire, soil strata, prostheses and biological tissue.
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The purpose of earthquake engineering is not to build strong and earthquake-resistant buildings that do not experience the slightest damage in rare and severe earthquakes. The cost of such structures for the vast majority of users will have no economic justification.
Instead, engineers focus on buildings that resist earthquakes' effects and do not collapse, even in severe external excitations. It is the most important goal of international standards in the seismic design of buildings.
Below I have mentioned some crucial points in reducing the seismic demand in reinforced concrete structures. If there is anything else that is not on the list, feel free to append:
1- Selecting suitable construction conditions with the desired soil type of seismic design
2. Avoid using unnecessary masses in the building
3- Using simple structural elements with minimal torsional effects
4. Avoid sudden changes in strength and stiffness in building height
5. Prevent the formation of soft-story
6. Provide sufficient lateral restraint to control drift through shear walls
7- Preventing disturbance in the lateral behavior of the structure by non-structural components
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Allow me to present another of my own seismic design proposals that I hope will solve all the problems of structures in the great earthquake.
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Dear Colleagues,
This Special Issue, "Numerical and Computational Methods in Engineering", aims to explore the latest advancements and applications of numerical and computational techniques in various engineering disciplines. It provides a platform for researchers and practitioners on which to share their innovative methodologies, algorithms, and computational tools that facilitate the analysis, design, and optimization of engineering systems.
The scope of this Special Issue encompasses a broad range of engineering fields, including but not limited to civil engineering, mechanical engineering, electrical engineering, aerospace engineering, and chemical engineering. It welcomes contributions that address fundamental principles, the development of novel algorithms and computational techniques, the implementation of computational models, and practical applications in a diverse range of engineering domains.
Keywords
  • applied mathematics
  • numerical methods for partial differential equations
  • computational mechanics
  • optimization algorithms
  • structural analysis
  • heat and mass transfer simulation
  • computational electromagnetics
  • multi-physics simulations
  • computational materials science
  • high-performance computing
  • data-driven algorithms
  • big data analysis
  • machine learning in engineering
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The provided text introduces a Special Issue on "Numerical and Computational Methods in Engineering." It emphasizes the exploration of advancements and applications in various engineering disciplines. The goal is to provide a platform for sharing innovative methodologies, algorithms, and computational tools that contribute to the analysis, design, and optimization of engineering systems.
The scope of the Special Issue covers a wide range of engineering fields, such as civil, mechanical, electrical, aerospace, and chemical engineering. It encourages contributions addressing fundamental principles, the development of novel algorithms, computational techniques, implementation of computational models, and practical applications in diverse engineering domains.
The specified keywords highlight key areas of interest, including applied mathematics, numerical methods for partial differential equations, computational mechanics, optimization algorithms, structural analysis, heat and mass transfer simulation, computational electromagnetics, multi-physics simulations, computational materials science, high-performance computing, data-driven algorithms, big data analysis, and machine learning in engineering.
In essence, the Special Issue aims to foster collaboration and knowledge exchange among researchers and practitioners in the field of numerical and computational methods, addressing both foundational aspects and their real-world applications across various engineering disciplines.
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While doing a structural analysis to check the plastic limit load of a component, the solution stops shortly before the end of the time step after successfully solving several substeps. I'd like to see the loads corresponding to the converged substeps. Is it possible to retrieve these loads through some apdl command?
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Hello Seyed Reza Jafari, thanks for your reply. But my question is how to read the value of the load applied by ansys during each time step?
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I’m working on research that will compare the performance of different structure systems of high-rise buildings, I’m going to use ETABS in this comparison, so I need to figure out exactly how does it calculate the wind load, so I took a very simple 3 floor building, the height of each floor is 11.48 ft and building is 98.5 x 98.5 in plan, then I will use the following: -
gust factor = 0.85.
Kd = 0.85.
Kzt = 1.00.
Imp Factor = 1.00.
Exposure C.
Wind Speed = 100 mph.
Kz (1) (First Floor) = 0.849, Kz (2) = 0.928, Kz (3) = 1.01.
qz(1) = 0.00256 x 1.00 x 0.85 x 0.85 x 0.849 = 18.47, qz(2) = 20.2 , qz(3) = 22.00 , qh = 22.00.
Windward Side
P(1) = 18.47 x 0.80 x 0.85 = 12.56 ft/lb2, P(2) = 13.74 ft/lb2, P(3) = 14.96 ft/lb2.
F(1) = 12.56 x 98.50 x 11.48 = 14 206 lb, F(2) = 15 541 lb, F(3) = 16 920 lb.
Leeward Side
P = 22.00 x 0.50 x 0.85 = 9.35 ft/lb2.
F = 9.35 x 98.50 x 11.48 = 10 575 lb.
I apologize for the very long introduction but now comes the problem I face, total force from the windward side = 46 668 lb, total force from the leeward side = 31 727 lb, total external force = 78 395 lb, I have problems calculating the internal pressure to get the final value that’s on ETABs ( 64 464 lb), need assistance please.
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Dear Mohamaed Ashraf
you working on high rise building but you choose 3floor and the height of each floor 11.5ft, so it is a low rise building(<60ft). you need to find wind pressure P = qh[ (GCpf ) – (GCpi)] (lb/ft2) (N/m2)
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How to show two peptide structures side by side on Pymol. I have 100 PDB files. I want to show all the 3D image structures side side in a two-dimensional array form. How could I do the same in Pymol?
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You would have to labels to a component of the different objects, e.g. define a pseudoatom in a suitable position, and then label this pseudo atom. https://pymolwiki.org/index.php/Label.
When creating static images, e.g. figures for publications, I prefer to export the molecular images as high-resolution ray-traced png files, and then do most labelling in a generic graphics program.
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There is nothing worse for curb appearance than chipped and cracked concrete, particularly in steps. But you don’t have to put up with that blight any longer. By the result of weather changes exerted on an existing construction for prolonged time, it causes contraction and expansion those gradually results concrete steps cracks and break up with time.
Dear researchers, I would like to get expert opinions on how to fix this issue with,
optimum efficiency
low cost
prolonged sustainability .
Your answers are highly welcomed.
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Dear Doctor
Go To
Cracks Evaluation of Reinforced Concrete Structure: A Review
hmad Zaki et al. 2021 J. Phys.: Conf. Ser. 1783 012091
"Abstract
Many reports state how serious the problems associated with cracking in reinforced concrete (RC) structures worldwide. The cracking can cause damage and destruction to RC structures. The cracks are the damage to RC structures that require repair or replacement. Analysis of the damage level as early as possible on the RC structure cracks can reduce the greater impact and streamline the cost of repairing the concrete structure. Therefore, non-destructive testing (NDT) method is needed on the RC structure, namely: visual inspection technique. The image obtained from the visual inspection is then analyzed using image processing. After that, the concrete structure with cracks is tested for quality (compressive strength) using the rebound hammer technique with a rebound index. From the image processing and rebound index results, the damage from the cracks that occurred can be concluded so that the repairs become more effective and efficient."
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Are its faces polytopes?
Is there any information in the literature on the geometry and topology of saddle polyhedra?
Can we use them to construct structural triply periodic minimal surfaces?
An attempt to answer some of these questions in:
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José Luis Junquera, Saddle polyhedra are three-dimensional objects with curved faces. They are not polyhedra in the traditional sense, because polyhedra must have flat faces. However, saddle polyhedra do have some properties that are similar to those of polyhedra. For example, they have an Euler characteristic, which is a topological invariant that is defined for all three-dimensional objects. addle polyhedra are the only other three-dimensional objects known to have an Euler characteristic of 2. This is an interesting fact, because it suggests that saddle polyhedra have some topological similarities to spheres and flat-faced polyhedra. The two saddle polyhedra that are known to exist are the saddle tetrahedron and its tessellation. The saddle tetrahedron has four curved faces, six edges, and four vertices. Its tessellation is a three-dimensional tiling that fills all of space. Saddle polyhedra are a relatively new area of research, and there is still much to learn about their geometry and topology. However, the fact that they have an Euler characteristic of 2 is a significant discovery, and it suggests that these objects have some interesting properties.
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Complex graphical sketches are highly involved in Culmann's methods. Therefore, it is highly prone for getting deviations in magnitudes for resultant pressure on retaining wall. I would like to get suggestions from RG colleagues on why Culmann's graphical approach is mostly preferred in many research papers albeit Rankine's method is easy and precise in terms of equations and substitutions. I would welcome answers from both theoretical and practical perspectives.
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Rankine theory is specific to vertical and smooth wall. But culmann's graphical approach is also for inclined wall. I think this is major cause of choosing Culmann's graphical approach over Rankine theory.
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Can you please recommend me any useful material that will help me to understand CDP model generally used in ABAQUS for concrete materials? I have read some fundamental papers like Lee and Fenves, Lubliner et. al., etc. to understand the theory behind it. I got it to some extent. Now, I am looking for something that describes CDP from practical point of view. My main goal is to understand the output that I am getting from my analysis.
Any sort of information will be greatly appreciated.
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Dear Sushil
Artcle: Calibration of a New Concrete Damage Plasticity Theoretical Model Based on Experimental Parameters.
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I have results from a load-deflection curve that behaves non-linearly. I need to convert this to a stress-strain curve and/or find the final Modulus of Rupture (MOR).
To do so, converting the deflection into strain is possible as per ASTM D790
εf = 6Dd/L^2, where D is the maximum deflection, d is depth and L is the span length.
I would like to convert the load to stress as well, however, the conventional equation from beam theory is not applicable past the yield point,
σf = 3PL/2bd^2, where P is the load.
I'm aware that it somehow involves the neutral axis and the modified I (moment of inertia) but struggling to make sense of it. The end goal is to find the MOR.
Any help about this is appreciated :)
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In my opinion, to reconstruct σ-ε diagram from known load-deflection curve is a kind of inverse problem. Generally speaking, such problems are ill posed. You can proceed from some particular approximation of σ-ε diagram (for example, bilinear), find the solution of direct problem (load-deflection curve) and then vary the parameters of σ-ε diagram to find those that give a minimum deviation (eg, the mean square) of load-deflection curve from the experimental one.
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I am writing a FEA solver (using MATLAB) for computing stresses and stresses in a 2D rectangular plate with an elliptic hole (rotated to an angle). I computed the global stiffness matrix using Gauss quadrature (3 gauss points) and have also calculated stress and strain in each element.
How do I calculate the nodal stresses from the element stress values. I think the element stress values that I obtained are calculated at the centroid of each element. How do I extrapolate/interpolate these values to get nodal stress and strains?
Please advise with some resources or tutorials or solved examples.
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Thank you for a detailed response. I could not find the resources you've mentioned but I did find other papers on the MLS method.
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I have performed a certain set of nonlinear dynamic analyses on an RC (Reinforced Concrete) frame that I designed on SAP2000 using the Indian Standard Codes. Since the numerical model is not based on any existing building, I fear that someone might ask me how I would validate my model, which on their part, is justified. What could I possibly say as a satisfactory response?
For some reason, many people are often reluctant to share their design details, so the question regarding validation seems a bit tricky.
Thanks in advance.
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Thank you Pavlo Pavliuchenko sir for this insightful answer. This does clarify a lot of things. Of course, covid induced restrictions did play a huge role in limiting us from going out to search for experimental data or real-world data that we could have used for our FE model. However, we can surely find some literature to validate the results. Thanks
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I understood SM is moment per unit width. But i dont know how to get integrated moment at mid span.
Then I tried to use free body cut to show mid span moment. (SI unit:force=N, length=mm)
However, I found that the moment I get for 500(D)x100(W) and 500(D)x400(W) are the same (e.g both 6.1e8) from free body cut, if that moment multiply flange width, total moment will be different in section 500x100 and 500x400 but their length and load are the same.
So I just wonder if moment from free body cut(blue arrow) is already represent total moment at mid span?
Thanks
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I guess the bounday conditions and loading you're applying make the problem STATICALLY DETERMINATE. If so, then your section moment at any cut along length are going to be the same as they do not depend on section properties; rather purely statics of the problem (sophomore year coursework - statics ) :)
if this is not the case, then you have to explain what you're trying to solve. problem parameters and details (loading, bc, materials, etc.)
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I have created a model of high rise tower and tried modal analysis in Ansys workbench Mechanical, but I am not getting frequency values and mode shape. Value of frequency is showing 0 at all modes. Can anyone suggest why this is so?
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Since you've mentioned all natural frequencies are zero it also important to know how many modes are extracted from Ansys?
If you have multiple bodies which are not constrained, each one will add rigid body modes (RBMs) to the problem, and you will end up with many zero frequencies. For instance, with no constraints a body in 3D will have 6 RBMs. If you have 2 such bodies, you will have 12 zero very close to zero natural frequencies.
You can plot the mode shapes that have zero natural frequency to visualize if any of them is not constrained properly and moving freely with respect to other parts. Exaggerate the mode shapes to observe the motion better. If this is the case, you need to define the boundary conditions properly. This might be due to the improper definition of contact surfaces in Workbench. If that is the case, you need to bond such surface to each other.
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As we studied in our academic courses, we know several shapes of beams:rectangle,special shapes and T or L beams.
So in softwares such as Etabs and Robot, are they take into consideration L or T shape beams?
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Yes, most modern structural analysis and design software programs, including Etabs and Autodesk Robot, are capable of analyzing and designing reinforced concrete T-beams. These software programs typically include tools for modeling various types of beams, including T-beams, and can perform various types of analysis, such as load and stress analysis, to determine the strength and stability of the structure.
The software programs can also perform design calculations for reinforced concrete T-beams, taking into account the strength of the concrete and the reinforcing steel, and can generate reports and design drawings. The accuracy and efficiency of the analysis and design results depend on various factors, including the quality of the input data, the accuracy of the software models, and the expertise of the user.
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The most venerable professors and research scholars
Your critical comments, valuable opinions, scientific facts and thoughts, and supportive discussion on how can structural grammar and IC analysis be justified in the recent pedagogical and enhancement trends in EIP for EFL adult learners.
I shall be thankful sincerely for your kind participation.
Best,
Dr. Meenakshi
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In my opinion, it will depend on to what extent the language learner would like to view how the language works. I would say that if we opt to view language from the perspective of medium/tool in conveying messages or communication; incorporating structural grammar and IC analysis are beneficial to use the grammar correctly within the exact communication function to deliver the correct message by the encoder to the decoder.
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I found that modal frequency results between Opensees Navigator and hand calculation is different.
I assumed a simple truss model : cross section 0.04 m^2, mass density 5000 kg/m^3, elastic modulus 200 GPa, 3 nodes, 2 elements.
This truss model has 2 mode and 2 modal frequency. My hand calculation modal frequencies are 711.7625 hertz and 711.7625 hertz, respectively.
However, Modal frequencies from Opensees Navigator are 142.3525 hertz and 142.3525 hertz, respectively.
I wonder why two results have different. Does Opensees Navigator have postprocessing?
I'll post my Opensees Navigator files. Please describe the reason why two results have different.
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I checked your Opensees model files. You have defined two truss members with a value of 5000 for the density. For the truss member in Opensees, you must enter the density per unit length. The density per unit length for your model is equal to: 5000*0.04=200kg/m. Just define the value of 200. I did this correction for your model and got a frequency of 711.7625 Hz for the first two modes.
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In his name is the judge
Hi
I think the best way to assign the nonlinear effect of steel components like beams that to model it with a plastic hinge.
So To build a nonlinear model of a one-story steel structure I use the Modified Ibarra – Krawinkler model to model my beam. In fact, I model a beam with two hing (zero length element) at the start and end and one elastic beam in the middle.
I used material developed by Lignos and Krawinkler named uniaxial material Bilin and here is more information about this material
After all, when I extract the output belonging to the stress-strain of this material under seismic loading like Kobe I get something like this diagram. (kobe0.5g) based on
"Ibarra L.F., and Krawinkler, H. (2005). “Global collapse of frame structures under seismic excitations”, Rep. No. TB 152, The John A. Blume Earthquake Engineering Center, Stanford University, Stanford, CA."
named article and this diagram (ref1) the stress-strain shows the right modeling and performance. consider that my record is near fault and the diagram of reference also belongs to near-fault loading.
If I use the 1g scale for the Kobe record I get this diagram (kobe1g) and here is the diagram of the 2g scale for the Kobe record (kobe2g) So my best shot is this when the record multiply and the ground accel become higher the material reaches the capacity of its deterioration very more quickly(In fact after a short time the strain of material switch between 1e10 an-1e10 and strain is between about -2 and 2) but it's a little non-sens for me in the other hand there is one benchmark( in the reference is named it before this benchmark is for standard loading) diagram for this material stress-strain (logos) and my diagram is different with it.
In the end here are the 1M$ questions
1- why when I give more scale to record the diagram become like that?
2- and why my diagram is different from the benchmark stress-stress of material?
Any help is greatly appreciated.
Take refuge in the right.
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Dear Mohammad,
Please note that pre-cap plastic deformation (rotation) capacity is relative, not absolute. It represents the distance between the yield and maximum moments. Although in the two diagrams the absolute maximums are different, the distance between the yield and maximum moments are the same.
Regarding your second question, please make sure you assigned monotonic backbone parameters with some cyclic deterioration. From the rapid in-cycle deterioration (softening) in the diagrams you have sent, I suspect you have assigned the first-cycle (cyclic) backbone parameters.
BR.
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Hello All... I am trying to install Gromacs on windows using conda i have attempted to run "conda install -c bioconda gromacs_py" but it's not working. Any recommendations shall be highly appreciated.
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Ryan Gourlie Sir, I am working with Windows OS and the mentioned one is for Linux and mac. I have also tried this but it's not working. I am working in an environment in conda and I want to install it there. Is there any way I can import it from Cygwin to conda environment or from user apps to conda env?
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In his name is the judge
I want to build some parametric structures. my objects is period of first mode, eccentricity and (frequency of torsional mode/frequency of transitional mode). So I decide to use NSGAII for make my parametric structure.
Inputs of optimization are transitional mass, rotational mass, length and width of structure and objects are period of first mode and (frequency of torsional mode/frequency of transitional mode) and in each one I assume eccentricity constant.
So I think there is a problem. I think there is a relation between rotational mass and transitional mass with respect to length and width of structure and eccentricity of mass.
If my guess is true I have to remove rotational mass from my inputs and use the relation instead.
So my big question is
Is there any formula to evaluate rotational mass based on dimension, eccentricity and transitional mass in rectangular plan?
wish you best
Take refuge in the right.
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If your structure is an 'office' or 'hospital' type building with concrete floors, so that the floors form rigid diaphragms at each storey, mass is associated with the translational response, and mass moment of inertia (MMI) is associated with the torsional response. You need to study an appropriate text on this, or an ETABS program manual, etc. Attached are formulae for calculating the MMI for typical floor shapes, including how to allow for these shapes being offset from the overall centre of mass.
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How to find the rotational mode shapes using an accelerometer that can measure the translational mode shape only in the modal analysis experiment for a cantilever beam?
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I would say that you need more than one sensing point to describe your shape; then you may derive the shape spatially. This is what I achieved with full-field measurements, please have a look to:
If the spatial description is too coarse, other authors have tried with closely spaced accereometers to get the same spatial derivation I did with non contacting measurements.
Best regards,
Alessandro
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I am modeling an underground structure with fixed support conditions around the exterior walls. I would like to apply different ground acceleration time history data into specific nodes (joints) of the structure. Is this possible in SAP 2000? I would appreciate any guidelines. Thank you very much!
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Hi Woongchan,
Yes, it is possible!
However, you need to convert the acceleration records into displacement records using SAP or any other seismic software. Then you define load pattern for each loading record and assign a unital displacement load on that node using the defined load pattern. Finally, define time history load case for using load pattern not acceleration. You may check Appendix B in my thesis on how to conduct multi-support excitation time history analysis using SAP2000.
Best,
Bashar
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in the flexural 3PB test, a concentrated displacement load would be applied to the top middle point of a beam. For modeling one-half of the beam using symmetry, which nodes or edges do you think should the roller and load point be assigned to avoid coincident of the BCs and errors relating to stress concentration in a nodal load point (after meshing, image attached)? is it not a better idea to assign the displacement load directly to the whole side edge using these BCs ( U1=0, U2=Value, U3=0, UR1=0, UR2=0, UR3=0)?
any idea would be appreciated.
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dear
Claudio Pedrazzi
thank you for your answer,
all these tricks are done for simplifying the model and to keep the number of surface contacts as low as possible (there are plenty in my case), also the exact E-Modules of the roller of the machine is not available.
As you said, applying the symmetry conditions to the side edge and the load to the top node may work.
your answer helped...
I will be following other ideas on this issue
God bless
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I am doing a structural analysis of natural fiber composite. I need to insert downward speed on a plate placed on top of a body and the other plate placed at the bottom of the body will remain fixed. I need to solve this problem to see the critical load and deformation induced in the body due to application of speed on the upper plate.
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Tank you
Claudio Pedrazzi
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I intend to perform a steady-state structural analysis on dog bone specimen that is loaded axially. The young's modulus is 200.02 GPa and a poisson ratio of 0.39. The analysis is intended to be in a linear state. This is intended to be performed on the APDL section. I am looking to become more of an expert in this field so any help in understanding this better would be appreciated.
Also experiments have been conducted so I do have stress vs strain data to use for non-linear analysis, however I am not very on how to go about it as I have found it difficult to model non-linear problems on ANSYS APDL
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Abdulsamad Adeniran , I am a bit lost on what you intend to do. Are you interested in conducting a finite element static analysis on the dog bone sample? If so, you can use either 3D or 2D PLANE elements in APDL. It's actually easier to have control over the element you use in APDL than ANSYS Workbench. It's also much more intuitive to run non-linear analysis in APDL.
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In his name is the judge
Hi
There is a fuzzy logic control system in python. The system contain 2 inouts and 18 outputs.
inference of system is mamdani and shape function used to be guassian.
Then in term of refine performance of the controller I need to optimize specifications belong to shape functions of both input and output. In order to that I need to use multi objective optimization.
We have 2 input and 1 output in case of this problem. I have developed 3 shape functions for each entrance and 3 for output and the shape function is gaussian so we have 18 parameters totally.
I defined my problem as a function in python. But notice this I there is not any clear relationship between input and output of function. It’s just a function which is so complicated with 2 inputs and 18 outputs.
I made my decision to use NSGAII algorithm and I really don't want to change the algorithm.
So I try every way to optimize my function but I didn’t find any success. By searching about python library which can do multiobjective optimization I find Pymoo as the best solution but I really failed to optimize my function which is complicated custom function, with it.
So It’s really my pleasure if you can introduce me a library in python or suggest me a way that I can use Pymoo in order to this aim.
wish you best
Take refuge in the right.
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You can stick with Mamdani Fuzzy System if it is comfortable for you to design a "workable" FIS. You probably don't need optimization if your FIS works satisfactorily. From the "workable" FIS to the "satisfactory" FIS, you probably just need make minor adjustment to the design parameters. That's the Spirit of Engineering Design.
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Hello everyone, I was modeling pultruded GFRP rectangular hollow sections for ITF boundary conditions. However, i am facing some errors while executing the job analysis. Can you please guide me how can i remove these errors from my model.
I have attached the abqus model, errors file and respective material properties.
Thanks you!!!
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Dear Raheel,
For your GFRP part, the Hashin Damage in Abaqus (both initiation and evolution) can be used only with Continuum Shell elements (and not the 3D Stress/C3D8R elements). You need to create a new Section with category of Shell and Type of Homogeneous or Composite. Then you need to replace this newly created section with your existent GFRP Section for your RHS Part. Next, you need to change your Element Type (in Mesh Module), for your RHS part only, to Continuum Shell/SC8R (you can find it in the Family list in the Element Type window).
I hop this helps!
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In order to analyze a component on which case hardening is done for a certain depth, for fatigue life.
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You model it as a bi-metal structure, ie. a body with two or more different materials within it.
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I have done a comparison by applying the hydrostatic pressure on the middle and top of the shell curve surface (Section Assignment: Shell offset = Middle or Top surface in Abaqus). In the case of the middle surface minimum deflection is 6.115 mm, but in the case of the top surface, the minimum deflection is 12.18 mm. The curve plate is simply supported from three sides.
I have attached images of the results.
Could anybody tell me, which one is correct and why?
Thank you very much
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Zuffain Hussan Can you share the underlying Abaqus models (.inp)?
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Dear Researchers,
I am looking for methods to mesh a twisted blade in order to get more structure mesh.
I tried several mesh size yet the quality metric are a bit bad.
I am analyzing regarding the skewness and the orthogonal quality.
My objective will be performing modal and harmonic in order to determine the stress distribution adequate to the natural frequencies.
Thanks in advance for your advise.
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Mohammed Lamine Mekhalfia I didn't receive an email.
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In recent years, there has been development of some innovative construction technologies that are changing the way we build. There are many new technologies that will have a significant impact on the future of the construction industry.
Today, construction companies are able to complete projects more quickly and efficiently than ever before. There are new technologies in demand for the future that will help with accuracy, sustainability and faster construction.
Based on your point of view, what are the types of construction that can be used in future?
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Dear Shuraik Kader,
In view of the increasing risk of an energy and climate crisis, eco-innovation-based, green building technologies will be developed in the future to build homes that are significantly more energy-efficient and resistant to the negative effects of climate change. Consequently, the future will mainly develop pro-environmental, energy-efficient sustainable construction. Perhaps it will also be environmentally neutral construction based solely on natural building materials.
Best regards,
Dariusz
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I am looking for information on the pressure tree roots (by expansion) can exert on structures as retaining walls and quay walls. Failure of retaining walls by root pressure is very common. Is there any way/model to determine this load?
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There are some experimental papers on force measurement by plant tree roots:
You may use an inverted analysis of paper B with rod theory to derive root pressure.
Hope it helps
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In his name is the judge
Hi
I'm trying to make a fuzzy controller in order to optimize my absorber performance in opensees(in python).
I use adaptive neuro-fuzzy inference system (ANFIS) toolbox in matlab to make fuzzy system as controller.
input data for fuzzy logic system are acceleration and velocity of absorber and the output data is force wich controller send it to absorber for performance improvement.
in fact i want controller learn ,based on velocity and acceleration of a point of structure, how much force need for turn structure into it's balance position.
note that quantity of force determine by fuzzy controller system and applying force part of absorbr job.
logically we have to assign come load to the point of structure wich absorber locate there and then get acceleration and velocity of absorber as input training data of fuzzy logic system.
but i realy don't know how can i do this.
note that i want to give force to structure in balance position, in the otherwise i think make train data is possible when using dynamic loading so i entirely confused here
if you have any suggestion i realy eager to hear it.
wish you best
Take refuge in the right.
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Mohammadhassan Eftekhar To train a fuzzy system utilizing neuro-adaptive approaches, input/output training data from experiments or simulations of the system to be modeled must be collected. In general, ANFIS training works successfully if the training data is completely reflective of the data characteristics that the trained FIS is meant to model.
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In his name is the judge
Hi
for using matlab facilities especially matlab controller like fuzzy have to sending and receiving data between matlab and opensees, in fact i want send two data as fuzzy controller form opensees to matlab after each time history step in opensees and then matlab send back one output to opensees.
to achieve this i have to connect matlab and opensees with openfresco it means i do hybrid simulation.
first is this possible to do this?
second is there any one do work like this, do hybrid simulation generally or specifically do hybrid simulation between matlab and opensees. if yes i am very thankful to share work with me or for some aim.
have to say i prefer not to use openseespy and i almost read all example and guide in openfresco site and even on each site but i cant do this right.
Any help is greatly appreciated.
Take refuge in the right.
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dear Abolfazl Najafi thanks a lot for this suggestion
i think there is a lack time between opensees anb matlab run time it means when tcl try to write text file, matlab needs to read more data in text file and give error
after all i think working with python and openseespy library is the best choice for this goal.
wish you best
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In his name is the judge
Hi
I want design cotroller in to control active force of damper.
On this purpose, i analyzed structure with damper, wich is tlcdg, and get data whic use for generate controller. data are accleration and velocity of damper as input and dampers force as output ( i mean force wich made by own damper under earthquake excitation, not active force).
here is anfis properties :
number of inputs are 2
number of outputs is 1
generate fis method is grid partition
number of membership function are 4 for each input
input membership function type is guass2mf
output membership function type is linear
opt method is "hybrid".
(have to say i tried different epochs membership function , .....)
Unfortunately anfis toolbox in matlab refuse to train and build Suitable fuzzy controller wich means error is too much in training, so this answer is not acceptable.
i have some idea for make it true but i'm not sure.
here is my ideas :
* first i think train controller with more or less data ( training data are about 2000 wich is under 100s earthquake excitation but when i reduce earthquake excitation to 10 or 15 seconds the error is acceptable however i think this solution is not good.)
* second maybe i must try one damper for training.
* the last idea is to assign force on the damper location and get acceleration and velacity for generate trianing data.
here is my data and shot frome my try.
Any help is greatly appreciated.
Take refuge in the right.
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Gracias por su sugerencia
Definitivamente revisaré
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I'm preparing Msc thesis regarding base isolation of buildings using rubber bearings, but before commencing my study I need to numerically verify an experimental work / shaking table test, but the problem is that I,ve been searching for quite a long time but yet to find anything useful, I've found many good papers but with missing information that makes modling of the experment imposible, thats why I need assistance in finding a proper research with complete information.
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Thank you very much, I'm going to check them out
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Which is the best way to attach the IMU sensor on the cantilever beam to measure it's acceleration so we can avoid errors and noise as much as possible ? (Is it by glue for example or wax or any other way) ...?
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Usually i use glue and have very small error in results.
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Which is the most crack direction is studied in a metal cantilever beam? When the crack is vertical or horizontal? (I mean if the crack propagates vertically or horizontally?)
And how each type of excitation(Bending, Axial,..) is sensitive for each type of crack shape and orientation?
I am asking for test purposes .. So I can use the crack direction that is more sensitive for measurements in my experiment.
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I think it depend on the type of load applied.
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Is there any effect of damage shape on the damage severity? And which do you expect has more severity of damage the holes shape or longitudinal shape? And why?
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I think this article may be helpful
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The psychological, inner mental activity, is a process. Usually it is hard approaching dynamic phenomenons by means of structural analysis, where intuitively things are seen in some static way. On the other hand, psychological activity is a very complex issue, and complexity can be frequently managed by systemic structural methods.
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Ken Wilber's Integral Psychological Maps are the most comprehensive
See Wilber, K. (2000). Integral Psychology. Boston, MA: Shambhala. PMCid:PMC1885698.
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I am currently testing a basic design for my research topic with a hollow cylinder.
The displacement was set as 0 on one end as a fix support and -5 in Y direction on another end.
The reaction solution i had is different from in Ansys Mechanical and i believe that the result generated from APDL was wrong.
The last screenshot is the result from APDL using .cbd file from Workbench mechanical
The result is still incorrect comparing to the result from Workbench Mechanical.
What is my mistakes here or any suggestion ?
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Claudio Pedrazzi
totally agree with your answer. he must select all nodes. you always find the solution of any problem.
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To whom it may concern...
Case shown in pictures below need to stop in front of it...
Starting with the way of supporting slab before casting.. the question appear...
Based on your engineering opinion, and supporting method that you might used... is what shown in pictures attached ,.. enough.. ?
Then... whom responsibility is that... if slab fail during casting process, as there will be additional loading of pumped concrete and labors also ...? where that will be the most important question....
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Dear Prof. Dr. Hussam, I think the work team has the responsibility, such as the supervising engineer, the work supervisor, the contractor, and the person responsible for the wooden mold
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To whom it may concern...
Case shown in pictures below need to stop in front of it...
What the mean of overload... What will be the meaning of calculated loading before design... and.... What really mean the structural design based on submitted data..
All, in general,.. knows that.. design start with converting functional use of the building to loading on structural element... then start design element by element ...
So, what might be the supposed loading to one story house... based on all adopted code... ? this is the first question..
Then what you think, .. or what the supervisor engineer might think the value of such loading on that slab shown in pictures attached... ? this is the second question...
Then at last... whom responsibility is that... if failure occur...? where that will be the most important question....
Limited education with low experiences causes such cases, ... or... we need to ask the supervised engineer if he care...
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Invariably the loading on one storey building roof with access is only `1.5 to 2 kN/m2 . and this is uni-formally distributed load. But if you pile up load in a small area more than the failure load of slab with concentrated load then the failure is imminent. this failure load can be calculated using yield line theory or by Hillerborg Strip method.
If you have this kind of loading then keep your props intact before you finish roof top work
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I am currently solving a static structural problem using ansys. I have given all the inputs but stress is not transmitting across the body. I have attached the files and I am bit new to ansys. Please guide me through the problem.
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It is not true that stress is not transmitting across the body. The results show a max von Mises stress of 1694 MPa, which is a sign of very localised stress singularity, perhaps at a sharp notch or edge. Such a high max value in the color band makes your whole body appear in blue color. Simply change the maximum scale value in your color band (e.g. 500 MPa).
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Dear all,
I would like to do a welding heat transfer analysis in 2D and map these results to a 3D model for conducting structural analysis. Is there any way to do the same?
Can any one suggest references for the same?
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I think one way to do that is to get the results from the 2D model and assign them as the initial conditions to the nodes having the exact coordinates( in just two directions (x and y)).
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I am doing a 2D pure shear isochoric strain analysis with 20% pure shear in ansys workbench using ansys static structural in ansys workbench. Previously in ansys mechanical apdl, there is a scope to enter displacement as a function of coordinates of nodes. The equations of my constituting boundary condition are
U = 0.2 *X and V = (-20/120)* Y. Here X and Y are the coordinates of the concerned node. How do I use them in ansys static structural analysis? Please guide.
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You can write a APDL script to do that. You need to write a loop (*DO) on your nodes, read coordinates and apply your desired load as a displacement.
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Hello,
I am studying the performance of 2 wing models (with the same size, constraints, loading and material properties but different material distribution) using Nastran. Wing A is lighter and 24% stiffer than wing B and that is demonstrated in the static analysis (under a distributed load on the top skin).
The two wings have about the same fundamental frequency (34.25Hz and 34Hz). Using the relationship f=sqrt(K/m), the difference between the two frequencies should be significant.
Also, the divergence analysis yields exactly the same displacement for the two wings.
Does any one know what could be causing such results? why the divergence displacement is not smaller for wing A (since it is stiffer) and its frequency is not much higher than wing B?
Thank you in advance for your input.
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Rossana Fernandes Can you share the two Nastran models (.bdf)?
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Dear researchers.
I am studying one way FSI using fluent and transient structural, my problem is that when I transfer the result directly from the fluent, I can not observe the correct deflection as the response should be a stepped as the excitation is a step function.
The relative total pressure on the structure surface is correct and I verified the plot.
I think that in transient I could not read the time steps even that I followed the correct step.
one of the solution I crossed with during web searching is to use external data transfer.
I know how to export pressure time value yet how to make the solver know that the pressure zone is as described in the attached picture?
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Long Chen first I tried to transfer the load directly to the structural solver yet the problem was that the feedback does not match with the input force, I had only one point, so I tried external data but I had a weighting error as I think I should also export the pressure coordinate but in that case we can not as I could not find any way how to export the pressure profile so I thought I may have an error in the simulation, I am doing it again.
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I will really appreciate if anyone could give some tips on the use of Lusas and SAP 2000 software for modeling and structural analysis. Thanks
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You can download the trial version and read user manual to practice the software.There are various online platforms offering a shirt term course for beginners like CAD Academy
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Can anyone suggest to me method to design fuzzy inference system (FIS) for MIMO structural damage detection (i.e. data distribution on the membership function, parameters of MF, Generate rules ... etc )
In my system there are 3 inputs and 2 outputs:
Inputs: Relative 1st Natural frequency , Relative 2nd Natural frequency , Relative 3rd Natural frequency
Outputs: Crack depth ratio , Crack Length
Note: I tried to use "genfis" By MATLAB it didn't give me reasonable results.
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Hi Murana Awad
Is it possible for you to share your data with me? I have some idea to solve your problem but I need your data.
I'm in touch by : ahmadi.v.1380@gmail.com
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Data science is a growing field of technology in present context. There have been notable applications of data science in electronic engineering, nanotechnology, mechanical engineering and artificial intelligence. What kind of future scopes available for data science at civil engineering aspects in the field of structural analysis, structural design, geotechnical engineering, hydrological engineering, environmental engineering and sustainable engineering?
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Hello Researchers,
The FEM discretized (meshed) geometry/domain is considered stiffer than the actual geometry/domain due to the assumption of variation of the displacement within each element. This is analogous to the displacement being constrained to vary in a particular fashion within each of the elements. This results in the stiffness of the discretized domain being greater than the actual domain. As the element size decreases (or the number of elements increases), the constraint on the displacement loosens due to the smaller size of the element and hence, the smaller constraint zone. Thus, the stiffness of the meshed domain decreases and approaches that of the actual domain as the number of elements is increased.
Based on the above reasoning, the natural frequencies (on increasing the number of elements) must converge from above to the actual value (i.e. converge from higher values to the actual value).
  1. Can this be considered to be strictly true?
  2. Has any deviation from it been observed (i.e. convergence from below or lower values to the actual value) and if so how can that trend be physically explained/interpreted?
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Dear Jatin,
Not always does a finer mesh result in a more exact solution. A mesh convergence study should always be performed to guarantee the descending trend of the error as the mesh size gets smaller.
Having this verified, yes, a finer mesh reduces the stiffness of the model. Because FE approximates the the PDE solution by forcing the element into specific modes of displacement which yields a stiffer element. But as the element size decreases, the FE solution converges to the analytical solution of PDE.
Eigenvalue can be physically interpreted as how stiff the structure is in the eigenvector direction. So it follows the same pattern as stiffness.
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I am looking for stress-strain data for steel to input for the plastic properties in Abaqus. However I cannot find any literature or experimental data on the matter. If full data is not available then the strain or deformation rate will also be helpful. Should I assume a 2% strain rate in the absence of other data?
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Is the data provided by Al Mouayed Bellah Nafeh of aluminum or stainless steel? As per the above draft, the yield stress is very high.
What would be the plastic strain-stress of structural steel ( Fe345, S275, S355)? Can I use the plastic stress-strain curve from material data provided by software SAP2000? Please make it clear. Thank you.
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How can I get the equivalent(effective) Young modulus and Poisson ratio of a multilayer structure? A structure like the below picture. the structure is consists of Si, Al2O3, and Al metal thin films. They must be simplified into one equivalent layer.
Thanks.
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So If a column isn't casted exactly in the intended location according to the structural drawings, and the centre of this column is moved 3 cm away from it's original location.now in the ACI code, accidental eccentricity is taken into account in the column design equation,so the question is how to check If that eccentricity is within the allowable range? According to the ACI?
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ACI already recognizes a minimum eccentricity in the column strength equation. That is why if you draw out the interaction diagram it starts off with a horizontal line from the vertical axis (P). The point where the horizontal line is no longer horizontal is the minimum eccentricity (emin=M/P). This is obviously slightly different for each section given the variables (f'c, section dimensions, rebar pattern, etc), but is considered nonetheless. That is the only "minimum eccentricity" that I'm aware of for short columns.
Slender columns do require a minimum eccentricity of 0.6" + 0.03h from ACI 318, but that is only for determining if a column is slender or not and to use with a slender column. It's not to use with a short column.
I hope, I have answered your question.
Regards,
Pravin Kumar
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While doing profile matching in full prof chi-square value is stuck at 12. When I try to refine u,v,w parameters their value reaches up to 38. What might be the possible reasons for the non-refinement of these parameters?
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Typically chi^2 is expected to decrease upon refining further parameters, if the refinement is well-behaved. As chi^2 increases, this suggests that the refinement is NOT well behaved at that point. This suggests high correlation of the refined paramaters push the refinement into a direction where everything is even poorer (you should see than in the visible quality of the fit, which should get poorer.). It is typically a sign for high correlation of the refined parameters, which can well be for uvw. This is in particular the case, if other parameters are being refined which do the same on the calculated profile as uvw. This depends, of course, on the details of you profile function and its refined parameters, and the history of your refinement. Based on this, and in view of the quality of your refinement do YOU have the feeling that you should touch u, v, w? I do not mean chi^2 (The way how people deal with their counting statistics frequently makes this number meaningless, unfortunately), but I refer to the agreement between observed and calculated profile!
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Structural analysis and morphological analysis
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Yes you can
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in his name is the judge
hi
I wrot a sub code on opensees for active tlcd or tuned liqiud gass damper (tlcgd) and assign it to some structures, it seems worked correctly.
In next step i want to optimize tlcgds location on each story with some objects like max dislacement or torsion ratio and ... so i have to use multi objective optimization (which may NSGAII algorithm is the best choice) code or toolbox on matlab and simulink. For this purpose i want to run NSGAII algorithm in matlab, then algorithm Calling my code in opensees (tcl) and run it, after that NSGAII algorithm modify damper location (in opensees code) after each timehistory analysis In order to improve objectives and then analysis my code again and again until find best location for dampers.
Note that I actually want to changing dampers location be part of the NSGAII algorithm and the algorithm itself automatically relocation the dampers to get the best answer.
one best solution may use openseespy but i think it's not free access and i can't get it from iran, So i think realyhead Over heels in this case.
Any help is greatly appreciated.
Take refuge in the right.
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I think that's the best answer
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What can cause severe bending conditions on the wind power plant's tower(only the tower part)? I assume that as the wind hits the blades it create a bending moment which vary linearly from wing tip to wing base. This moment will be transferred from blade's base to the top of the tower ( we have then a model like a beam with one end fixed and a bending moment on top). And I think that this moment has larger condtribution to tower's bending than the force coming from the wind as it hits the structure. Correct If I am wrong.
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Your interpretation is correct. The lateral loading due to wind and the moments due to rotating blades result in the problem.
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Hi,
Can any one please let me know how to configure ABAQUS solver for ANSYS workbench? So I can run simulations using ABAQUS solver which are pre-processed in ANSYS.
I read the help file, but I'm bit unclear what to do!
Thanks in Advnace!
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use an FEA modeler or external model then connect it to your step
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Hello friends
Nowadays I am trying to use Code_Aster to simulate CABLE . I want to know how to add a force like this F=0.5*velocity^2 on selected nodes?
And how can people add a triangle distributed force on a moving cable whose coordinate is changing with time .
Thanks for your help in advance.
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if you have a time-dept simulation, you can create a multiplyiting function with LIST_REEL and DEFI_FONC.
Franco
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Is the only way to differentiate between short and long coloums according to ACI is through slendeness ratio? Is there an easier approach?
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Dear Ali,
Columns can be broadly classified as short and slender columns based on their slenderness ratio. The slenderness ratio of a concrete column is defined as the ratio of its effective length le to its least lateral dimensions. The effective length is the unsupported length multiplied by a factor usually specified in the design codes depending on the end conditions of the column. Each code has its own criteria for classifying columns as either short or slender.
In this regard, I am attaching a thesis, where all the details have been given in more detail. I hope this will help.
Regards,
Pravin
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Structure Erection and Civil Works
1)Brief on civil foundation and, erection of supporting structures.
2) Fixing the foundation of the structure and, the grounding considerations.
3) Installation of mechanical structure
4) Foundation: Reinforcement and Shutting other balance of systems
5) Mechanical safety aspects.
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This is a good question.
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What should be done if items did not load in EFA?
should they be discarded? Or that means that they are unique and do not have partners?
What if these items are important or represent our dependent variables ? Can we include them as single items?
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Faten Amer, Usually items not loading on their respective constructs are discarded. However, at times discarded items can be combined to make a new construct.
Robert has already given you advice regarding single items.
Can you share a little more information regarding the EFA, so that we could together see what you have done and how could we help you further? Information such as:
- Which extraction method are you using?
- How the number of factors was identified?
- and, which rotation method was employed?
There is a common misconception between PCA and EFA, and at times right parameters (above) not selected. Consider reading the following article, if not already done:
Costello, A. B., & Osborne, J. (2005). Best practices in exploratory factor analysis: Four recommendations for getting the most from your analysis. Practical assessment, research, and evaluation, 10(1), 7.
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What are the programs which can be used for structural modeling?