Structural Analysis - Science topic

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.

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.

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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.

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?

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)

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.

Dear Doctor

Go To

"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."

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.

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.

Dear Sushil

Hi Janeshka Goonewardena,

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.

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.

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

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.)

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.

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.

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.

Dear Jae Min Lee

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.

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.

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?

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.

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

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

dear 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

Tank you

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.

This book (https://www.amazon.com/ANSYS-Mechanical-Finite-Element-Analysis/dp/0128129816?asin=0128129816&revisionId=&format=4&depth=1) can help you get a deep dive in APDL.

Hi Mohammadhassan Eftekhar

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.

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!

You model it as a bi-metal structure, ie. a body with two or more different materials within it.

See:

Zuffain Hussan Can you share the underlying Abaqus models (.inp)?

Mohammed Lamine Mekhalfia I didn't receive an email.

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

There are some experimental papers on force measurement by plant tree roots:

A: https://academic.oup.com/jxb/article-abstract/45/1/95/476383?redirectedFrom=fulltext#no-access-message

B: https://academic.oup.com/jxb/article/67/19/5605/2236186

You may use an inverted analysis of paper B with rod theory to derive root pressure.

Hope it helps

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.

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

Querido Jose Roberto Cagigas Velásquez

Gracias por su sugerencia

Definitivamente revisaré

Thank you very much, I'm going to check them out

I think this article may be helpful

Ken Wilber's Integral Psychological Maps are the most comprehensive

totally agree with your answer. he must select all nodes. you always find the solution of any problem.

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

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

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).

Anoop Pillai

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)).

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.

Rossana Fernandes Can you share the two Nastran models (.bdf)?

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.

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

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

This blog may help

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.

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.

Dear Mostafa Shabani

Kindly check these papers:

Ali Al-rubiay

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

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!

Yes you can

I think that's the best answer

Your interpretation is correct. The lateral loading due to wind and the moments due to rotating blades result in the problem.

use an FEA modeler or external model then connect it to your step

if you have a time-dept simulation, you can create a multiplyiting function with LIST_REEL and DEFI_FONC.

Franco

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

This is a good question.

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.