Science topic

Composite Structures - Science topic

Explore the latest questions and answers in Composite Structures, and find Composite Structures experts.
Questions related to Composite Structures
  • asked a question related to Composite Structures
Question
3 answers
Are layered composites and structural composites different?
Relevant answer
Answer
Laminated composites are one kind of strucural composites which the alayers containing directional fibers and matrix are overlapped/arranged conveniently according to each loading objective.
For example, sandwich panels is another type of strucutral composites, with different arrangements and intended, normally, for lightweigth applications.
Please, see the classical book: Composite Materials in Maritime Structures of Shenoi and Wellicome, vol. 1.
  • asked a question related to Composite Structures
Question
3 answers
The idea is to make a repair in a composite panel but i cannot find any properties like Ftu, Fcu, etc like in metals. We need to be conservative in this case where can i find values for composites structures?
Relevant answer
Answer
Please try to check out this source.
Guidelines for Aircraft Composite Panels
  • February 2020
  • INCAS BULLETIN 12(1):217-228
  • DOI: 10.13111/2066-8201.2020.12.1.21
  • License CC BY-NC-ND
  • asked a question related to Composite Structures
Question
5 answers
I have a 3D orthogonal woven composite structure with warp, weft, and binder yarns oriented in three directions. After modeling these yarns, I imported them into Abaqus as parts. I modeled the yarns as solid elements and assigned their material properties, including elastic, density, and Hashin damage properties, to each section. For meshing, I used C3D8R elements for each yarn. I set up the appropriate impact conditions. However, I am encountering an issue with the Hashin damage model. In Abaqus, I consistently receive the error message: "Hashin damage initiation criteria cannot be used with element 1 instance binderyarn-1-1."
Could you suggest any strategies to model this using the Hashin criteria without implementing a UMAT subroutine? How can I resolve this issue?
Relevant answer
Answer
Zeynep Akyazıcı Sure please send it in message here or tufail_mabood@yahoo.com
  • asked a question related to Composite Structures
Question
2 answers
I've conducted FE analysis of composite structure as shown figure. However, the strain on the metal surface does not match the experimental values. I am new to FEM and I am having trouble understanding the cause of this. Interface1 is applied friction coefficient of 0.7, and Interface2 is applied friction coefficient of 0.3. I use Ansys mechanical.
Please accept my apologies for my poor English.
Relevant answer
Answer
Hello!
It is a bit hard to answer your question without more context. Nonetheless, if the strain on the metal surface doesn't match the experimental values, then I would assume that either your contact definition or the friction coefficient between the two surfaces is not correct. However without more information it is difficult to provide more assistance.
I am curious, how did you measure the strain on the surface experimentally? And did you measure the fiction coefficient between those two surfaces experimentally?
  • asked a question related to Composite Structures
Question
56 answers
I use Abaqus for dynamic analysis of composite structures. In Abaqus, the damping can be defined at a material/element level and global level in the analysis. I am confused about the structural damping part in Abaqus and the damping at the material level as described below.
In the global level, the Rayleigh damping is Del = alpha x M + beta x K and the Structural Damping will modify the global stiffness matrix by a factor 's' where the stiffness matrix will be Ks=sK. 's' is the structural damping factor.
According to many textbooks, they take into account the effect of the structural damping by assuming an equivalent viscous damping ratio which could be added to the one from material damping when calculating the alpha and beta values in the Rayleigh Damping model.
In the material level, the number of elements, volume, and density of the elements alongside the alpha and beta values determine the damping matrix. I wonder if the alpha and beta values are the same as the global ones. I suspect they will be different because in the global level, the natural frequency and damping ratio of the entire model are used to calculate the alpha and beta values.
Your advice on these issues is highly appreciated.
Relevant answer
Answer
Dear Doctor
"Material damping can be defined:
  • for direct-integration (nonlinear, implicit or explicit), subspace-based direct-integration, direct-solution steady-state, and subspace-based steady-state dynamic analysis; or
  • for mode-based (linear) dynamic analysis in Abaqus/Standard.
Rayleigh damping
In direct-integration dynamic analysis you very often define energy dissipation mechanisms—dashpots, inelastic material behavior, etc.—as part of the basic model. In such cases there is usually no need to introduce additional damping: it is often unimportant compared to these other dissipative effects. However, some models do not have such dissipation sources (an example is a linear system with chattering contact, such as a pipeline in a seismic event). In such cases it is often desirable to introduce some general damping. Abaqus provides “Rayleigh” damping for this purpose. It provides a convenient abstraction to damp lower (mass-dependent) and higher (stiffness-dependent) frequency range behavior.
Rayleigh damping can also be used in direct-solution steady-state dynamic analyses and subspace-based steady-state dynamic analyses to get quantitatively accurate results, especially near natural frequencies."
  • asked a question related to Composite Structures
Question
1 answer
I wanna make a composite structure including two oxide minerals, in common surface in materials studio software.
Relevant answer
Answer
The specific steps may vary depending on the version of Materials Studio you are using. It is recommended to consult the software's documentation or tutorials for detailed instructions on building composite structures.
  • asked a question related to Composite Structures
Question
1 answer
Hypersonic vehicles, which travel at speeds greater than Mach 5, experience extreme thermal and mechanical loads during flight. The objective of this research is to investigate the behavior of composite materials at different length scales, ranging from the microstructure of individual fibers to the macroscopic behavior of the composite structure, under hypersonic conditions. The research would involve developing advanced computational models and simulation techniques to predict the mechanical response, thermal behavior, and failure mechanisms of composite materials in hypersonic environments.
Relevant answer
Answer
Hypersonic vehicles, traveling at speeds greater than Mach 5 (approximately 3,836 miles per hour), encounter several significant thermal and mechanical loads that impact composite materials.
Here are some specific aspects of these loads:
Thermal Loads:
a. Aerodynamic Heating: Hypersonic flight generates intense aerodynamic heating due to the high speeds and air compression. The friction between the vehicle and the surrounding air leads to a substantial rise in temperature, causing thermal loads on the composite materials.
b. Thermal Gradients: The extreme thermal environment of hypersonic flight results in significant temperature gradients across the vehicle structure. This creates thermal expansion and contraction within the composite materials, which can induce internal stresses and potentially affect their mechanical behavior.
c. Thermal Shock: Rapid heating and cooling cycles, caused by the transient nature of hypersonic flight, subject the composite materials to thermal shock. This can lead to localized temperature variations and thermal stresses, potentially affecting their structural integrity.
Mechanical Loads:
a. Aerodynamic Forces: Hypersonic vehicles experience intense aerodynamic forces due to the high speeds and air density. These forces generate significant mechanical loads on the composite structure, including bending, compression, tension, and shear.
b. Vibrations: Hypersonic flight can induce vibrations and oscillations in the vehicle structure. These dynamic loads impose additional mechanical stresses on the composite materials, which may affect their fatigue resistance and overall performance.
c. Shock Waves: Hypersonic flight involves the formation and interaction of shock waves. The interaction of shock waves with the vehicle's surface can result in high-pressure loads and impulsive forces, imposing mechanical stresses on the composite materials.
Understanding and analyzing these thermal and mechanical loads is crucial for designing composite materials that can withstand the extreme conditions of hypersonic flight. Advanced computational models and simulation techniques are used to predict and study the behavior of composite materials at different length scales, allowing researchers to assess their mechanical response, thermal behavior, and failure mechanisms accurately.
  • asked a question related to Composite Structures
Question
2 answers
I'm working on my thesis about reliability analysis of composite structures. Can I use maximum deflection of the plate structure as failure criteria to define limit state function to perform reliability analysis or I should use conventional failure criteria's (i.e. Tsai-Wu criteria)
Relevant answer
Answer
Good day!
Here, there is a difference between the material failure criterion and the specific structure failure criterion. In general, the nucleation of material damage is not necessarily a condition for the failure of the structure as a whole (subcritical damage), also the structure can lose its functionality without accompanying material damage (loss of stability, change of shape, etc.). If for a specific structure and for specific conditions it is more convenient for you to use simplified criteria, for example, strain-based one, then it should still be justified quantitatively, including on the basis of generally accepted criteria for the materials fracture.
  • asked a question related to Composite Structures
Question
4 answers
I have submitted my manuscript to Steel and Composite Structures Journal two days ago. However, until now, I have not received a confirmation email from this journal. At the end of the submission steps, it was written that "Congratulations! Your Submission has been completed!"
Is this normal? What should I do now?
Relevant answer
Answer
I agree with Dr Kaleeswaran Balasubramaniam that patience is required for now (beyond getting official confirmation, as I suggested before). Some of the posts on RG tell the story that other people were waiting for a very long time (up to two years) to get a decision. That is assuming they got acknowledgement in the first place, which is obviously what you are missing.
  • asked a question related to Composite Structures
Question
3 answers
Myself Nekin Joshua R, Research scholar from Vellore Institute of Technology(VIT), Vellore. I need a drop weight testing facility.
Please let me know where it is available in India ( Preferably nearer to Tamilnadu and also suggest the testing facility all over india).
Relevant answer
Answer
Drop Weight Impact Testing Machine is available in VIT it self. Please verify it once again before going 2 other college sir. All the best.
  • asked a question related to Composite Structures
Question
2 answers
The question asks for a description of what information can be obtained from High Performance Liquid Chromatography (HPLC) data regarding milk oligosaccharides. The answer to this question may include details about the composition, structure, and concentration of milk oligosaccharides that can be analyzed through HPLC.
Relevant answer
Answer
You may want to invest some of your own time researching the answer to this general homework question. *Learning HOW to research a question through study and reading is one of the most important skills you can learn as a student.
  • asked a question related to Composite Structures
Question
2 answers
Myself Nekin Joshua R. I like to do my research in Biomimic structures like Nacre, Auxetic, Conch Shell, Hexagonal cellular structure, Hourglass structure, Bouligand Structure.
And 3D print the structures in FDM and like to test the mechanical properties, Ballistic performance, Impact test.
I need to select any one bimimic structure and need to analyze. Please help me to identify which one structure has more energy absorbing property and Armor applications.
Please tell me which one structure I can select.
Relevant answer
Answer
There are several biomimetic structures that are known for their energy absorbing properties and potential use in armor applications. Some structures that you may want to consider include:
  1. Nacre: Nacre, also known as mother-of-pearl, is a material that is found in the shells of some mollusks. It is known for its high toughness and energy absorbing properties, making it a potentially useful material for armor applications.
  2. Auxetic materials: Auxetic materials are materials that exhibit a negative Poisson's ratio, meaning that they expand in the lateral direction when stretched. This property makes them highly energy absorbent and they have been explored for use in armor applications.
  3. Conch shell: The conch shell is a type of shell that is known for its toughness and energy absorbing properties. It has a complex microstructure that is thought to contribute to its mechanical properties, making it a potential candidate for use in armor applications.
  4. Hexagonal cellular structure: Materials with a hexagonal cellular structure, such as honeycombs, are known for their high energy absorption and have been explored for use in armor applications.
  5. Hourglass structure: Materials with an hourglass structure, such as those found in some sea urchin spines, have been shown to have excellent energy absorbing properties and may be useful in armor applications.
  6. Bouligand structure: Materials with a Bouligand structure, such as those found in some marine animal shells, have been shown to have high energy absorbing properties and may be useful in armor applications.
To answer your question, the specific biomimetic structure that is most suitable for use in armor applications will depend on the specific requirements of the application (where and how will it be used specifically?) and the properties that are most important, such as energy absorption, toughness, and weight. I recommend conducting further research and analysis to determine which structure is the best fit for your specific needs.
  • asked a question related to Composite Structures
Question
3 answers
I study the delamination of laminates upper and bottom skins of honeycomb composite structure simple supported from two sides and under bending stress.
I consider the developed tension on the bottom skin as the main peeling force that cause delamination.
Is my thinking correct?
Also, do you suggest textbooks?
Relevant answer
Answer
Delamination of laminates in a honeycomb composite structure can occur when there is a failure of the bond between the layers of the composite, resulting in the separation of the layers. In a simple supported structure under bending stress, the forces acting on the structure can cause the layers of the composite to experience different levels of tension and compression, which can lead to the development of shear stresses at the interface between the layers. These shear stresses can cause the bond between the layers to fail, resulting in delamination.
Your thinking that the developed tension on the bottom skin of the honeycomb composite structure can act as the main peeling force causing delamination is generally correct. The tension in the bottom skin can cause the bond between the layers to be subjected to tensile forces, which can lead to the separation of the layers if the bond is not strong enough to resist the forces.
However, it is important to note that the delamination of laminates in a honeycomb composite structure can also be influenced by other factors, such as the properties of the materials used to make the composite, the manufacturing process used to produce the composite, and the loading conditions applied to the composite. It is therefore important to carefully consider all of these factors when evaluating the risk of delamination in a composite structure.
  • asked a question related to Composite Structures
Question
7 answers
Hi everyone
I want to compare a monolithic polymer composite sample and a 3D-printed polymer composite sample. However, I need some references for this matter. Any contribution would be appreciated, kindly.
Relevant answer
Answer
Thank you. My objective is that the monolithic composites are based on the fact, that interaction and bonding between different materials may show various properties, in this case, lower mechanical properties rather than modern technologies such as additive manufacturing.
  • asked a question related to Composite Structures
Question
1 answer
Consider a composite fluid-conveying pipe with two equal-length spans. Using the "Oke et al. (2018) Composite structure" for single-span composite fluid-conveying pipe, I computed the "EI" mass of pipe and fluid values. But now I'd want to figure out the stiffness and masses of a two-span fluid conveying pipe with an equal length of 1 metre.
Is there any literature on multi-span composite fluid-conveying pipe calculations?
Relevant answer
Answer
To calculate the "EI" (Young's modulus times the moment of inertia) of a multi-span composite fluid-conveying pipe, you can first determine the material properties of the composite material used to make the pipe. The Young's modulus can be obtained from material testing or literature values, and the moment of inertia can be calculated using the cross-sectional shape and size of the pipe.
To calculate the mass of the fluid in the pipe, you will need to know the density of the fluid and the volume of the fluid in the pipe. You can determine the volume of the fluid by calculating the cross-sectional area of the pipe and the length of the pipe that is filled with the fluid.
To calculate the mass of the pipe itself, you will need to know the density of the composite material and the volume of the pipe. The volume of the pipe can be calculated using the cross-sectional shape and size of the pipe and the length of the pipe.
Once you have all of this information, you can use the following equation to calculate the "EI" of the multi-span composite fluid-conveying pipe:
EI = (Young's modulus * moment of inertia) + (density of fluid * volume of fluid * g) + (density of composite material * volume of pipe * g)
where g is the acceleration due to gravity (9.81 m/s^2).
This equation assumes that the pipe is simply supported and that the fluid is incompressible. If these assumptions do not hold for your specific case, you may need to use a more complex equation or model to accurately calculate the "EI" of the pipe.
  • asked a question related to Composite Structures
Question
3 answers
Mechanical engineering researchers who want to collaborate in writing ISI papers in the fields of vibrations, nonlinear vibration, plates, shells, and composite structures can send me a message on LinkedIn. If you wish, check out my recent articles at the link below:
Relevant answer
Answer
Dear Bale
It is my pleasure to work with you. I'll read your CV and send you a message.
Best regards
  • asked a question related to Composite Structures
Question
1 answer
What does PPA stand for in the sentence "Diaphragm forming (also referred to as hot drape forming) is one potential method for automating the production of low cost preforms for high volume applications (30,000+ ppa), due to lower capital investment compared to matched-tool forming." in the paper Double diaphragm forming simulation for complex composite structures?
Thank you a lot.
Relevant answer
Answer
just a guess: ppa = parts per annum,
based on a fact that paper author uses 'ppa' in a thesis (on pages 1, 2, and 21)
(without explanation) however, another thesis from same place
might justify the guess on page 2,
Good luck
  • asked a question related to Composite Structures
Question
25 answers
Hi all,
I have a problem in defining contact. There is a 3D composite wall model . I have used Surface to Surface contact. I receive these errors:
1-There are 3 unconnected regions in the model.
2-There is zero FORCE everywhere in the model based on the default criterion. please check the value of the average FORCE during the current iteration to verify that the FORCE is small enough to be treated as zero. if not, please use the solution controls to reset the criterion for zero FORCE.
Any idea is appreciated
Regards
Mahya
Relevant answer
Answer
Hello all,
At first open Abaqus Command from the start menu.
Its default address is C:\temp>. Change its address to your directory folder or copy your .inp file in C:\temp.
Next run a data check with the .inp file using following command:
"C:\temp>abaqus job=job-name.inp datacheck unconnected_region=yes interactive"
Enter (keyboard command)
If it asked for "Overwright?", answer: y
Enter (keyboard command)
After that datacheck completed with "Abaqus JOB job-name COMPLETED" message in the command window, open .odb file.
All unconnected regions can be viewed from following address:
Tools>display group>manager>create>Item:Elements, Method:Element sets, MESH COMPONENT 1, 2, 3, ...
Highlights items in the viewport.
Now you can find unconnected regions and fix them.
Regards,
M. Khodaei
  • asked a question related to Composite Structures
Question
3 answers
I need to know the online platforms available for submitting papers related to composite structure design and its study.
Since I am planning to submit for the first time, I need to know the formats and guidelines for the submitting papers online.
Relevant answer
Answer
Thank you so much for your immediate response madam
Nazanin Fallahi
I will go through all those mentioned.
  • asked a question related to Composite Structures
Question
1 answer
We fabricated the composite of PVA and nano-carbon-particles. The results of zeta sizer show that the size of PVA chains is increased and nano-carbon serves as a crosslinker. But in the case of rheometer's results, the viscosity of the above sample is decreased, which shows that nano-carbon serves as surfactant. The mechanical properties of composite structure are enhanced and XRD shows that the crystalline regions are less in the composite structure. What could be the possible reason of decrease in viscosity in your opinion ?
Here i have attached some XRD, zeta sizer and rheometer results..
Relevant answer
Answer
Is it PVA solution? By dynamic viscosity you mean the absolute value of the dynamic viscosity? Could you share the G' and G" values too? Is the carbon dispersion stable?
  • asked a question related to Composite Structures
Question
11 answers
Hello Researchers,
In the literature pertaining to sandwich panels, we often come across terms like "sandwich panels with a stiff core" and "sandwich panels with a soft core". How do we formally differentiate between these two? While the name itself suggests that for a stiff core the ratio of the shear modulus of the core to that of the face sheet is higher than the same ratio for a soft core. But is there any well-defined condition wherein which we can differentiate between a sandwich panel having a stiff core and one having a soft core?
I would also appreciate your suggestions/corrections on another point. As per my understanding for a stiff core, equivalent single layer theories based on FSDT or Reddy's Third Order Theory may give sufficiently accurate results. But for a soft core, refined higher-order theories usually with layerwise displacement assumption may be required for an accurate analysis.
Relevant answer
Распространение сэндвич панелей достигло небывалых высот. Они могут использоваться для самых разнообразных задачах в строительстве. Материал приготовляется из наполнителя, что находится в прослойке между металлическими пластинами. Покрытие бывает не только из металла, но и дерева или пластика.
  • asked a question related to Composite Structures
Question
14 answers
I am trying to model a reinforced concrete structure strengthened with CFRP bar. Could you please kindly tell me the key points to modeling CFRP bar? How do you define its material properties? Any help will be highly appreciated!
Relevant answer
Answer
  • asked a question related to Composite Structures
Question
6 answers
I am attempting to make a microscale RVE for composite structures using the M-T method. I am currently utilising MatLab to do so in two dimensions. However, I would like some further guidance on implementing the M-T method in Python. I would also like to progress the model into three dimensions and create a time-dependent continuum damage process.
Thanks
Relevant answer
Answer
In order to apply on viscoelastic materials, a computing technique based on the Mori–Tanaka mean-field approach was devised. The time-dependent response of a viscoelastic composite material may be determined using this approach.
I recommend reading the following article:
In addition, see this link also: https://github.com/tianyikillua/fiberpy
  • asked a question related to Composite Structures
Question
10 answers
Is it possible to do a multivariate analysis from a compositional statistical analysis perspective?
Without excluding measurements outside the compositional structure of a substance such as T C°,pH,EC...etc , Or are there conditions and restrictions for that?
Relevant answer
Answer
Thank you dear Rabah Kechiched again
  • asked a question related to Composite Structures
Question
3 answers
i searched many theoretical research paper but I cant find it
Relevant answer
Answer
As Thamarainathan already commented, the best option is to use VESTA. Next, you have the link to download the software (free):
  • asked a question related to Composite Structures
Question
1 answer
I'm planning to perform a low-velocity impact analysis on a sandwich composite consisting of top and bottom face sheets (Unidirectional fibre reinforced) with 4 plies each and a core (aluminium). The thicknesses are small relative to the other dimensions. After going through various materials, I'm still confused whether which one among the following combinations of elements I should go for -
1) SC8R (Core and face sheets)
2) SC8R (Core) and C3D8R (Face sheets)
3) SC8R (Face sheets) and C3D8R (Core)
4) C3D8R (Core and face sheets)
SC8R - Continuum Shell Element
C3D8R - Solid Element
  • asked a question related to Composite Structures
Question
5 answers
Any suggestions on how to define local coordinate system (LCS) in APDL for shell elements (SHELL 181) meshed on hemi-spherical surface.
All the elements throughout the hemispherical surface should have one reference orientation so that I can define fibre orientation in each layer with respect to one axis of element? I had implemented the procedure of example 3.9 from text book "Finite Element Analysis of Composite Materials Using ANSYS by Ever J. Barbero".
I modelled part of sphere (45 degress anle) and used Local Cartesian Coordinate System at Origin for elements meshed on the spherical surface but unable to get same element orientation for all the elements on the hemispherical surface.I am attaching the APDL code and the image of generated mesh.
I tried by defining different coordinate systems but unable to get certain fixed orienation for all elements on the spherical surface.
The purpose of this apdl code is to build FE model for designing Type 4 COPV (COMPOSITE OVERWRAPPED SPHERICLE PRESSURE VESSEL)
Please help me how to define orientation of fibers over the sphericle surface using SHELL 181 element.
Relevant answer
Answer
The exact apdl code which I had asked is available in the ANSYS FORUM.
  • asked a question related to Composite Structures
Question
6 answers
Hello All!
I am trying to model a composite in Abaqus, and specifically trying to capture the fiber realignment on loading.
One of the approaches I am considering is to.homogenise the fiber layer, and define anisotropic material properties that rotate on loading. This coordinate system should rotate following the direction of a prescribed edge of each element.
What would be the best way to model this rotating material orientation?
Relevant answer
Answer
You can check the following link:
  • asked a question related to Composite Structures
Question
4 answers
Hello everyone,
I am trying to model a DCB (mode-1) test for a carbon-fiber composite sample. However, I am a bit confused since I am very new to modelling and ABAQUS so I am looking for some help.
For composite structures, it is said that cohesive zone method is one of the best choice to model the initial crack area but in our experiments, we used a teflon film as crack initiator. That's why I am a bit confused. How could I model this teflon film in ABAQUS? Should I model it as a cohesive element with some values that I found on literature ? Does the element/material of the crack area has an effect on results ?
Any help would be appreciated. Thank you very much.
Relevant answer
Answer
Check out this paper, you will get some idea about what is CZM elements.
Regards,
W
  • asked a question related to Composite Structures
Question
8 answers
I modeled a concrete deck slab on top of steel girders in ANSYS APDL
but my results for the bending stress (X component stress) from ANSYS do not match what I obtained from hand calculations Using Mc / I
using Mc / I i obtained 29 MPa
and from ANSYS i got 10 MPa
i attached below my calculation as well as my model and elements used.
i used MPC184 rigid link to connect between the concrete deck slab shell element and top flange steel girder.
the slab is simply supported (roller and pin)
any idea what might be wrong?
Relevant answer
Answer
Zeinah Mohamad Elnassar can you pls tell me which case of bending stresses u r evaluating ??there are many bending cases😊 if u r calculating Quazi-static then developed deflection & stresses will not change over time..! & also Pls check which step u have calculated. It looks your results can be acceptable if you do same condition by changing number of elements..that we called mesh independent study...in those case u will achieve ur hand calculated values hopefully!!
👍
Regards,
  • asked a question related to Composite Structures
Question
3 answers
When can the Classical Laminate Theory (CLT) be applied in practice for analyzing composite laminates. I mean, under what conditions is it allowed to approximate the composite structure to be a lamina and hence, mathematically analyze and treat it as such? Can a composite airfoil be treated using CLT?
Relevant answer
Answer
dear Abdelrahman Baraka
pls look at this PhD thesis, and I hope you find your answer
  • asked a question related to Composite Structures
Question
4 answers
I have inventory data set of vascular plants using systematic distribution and two data sets for large mammal species, 1. camera trap data set and 2. rangers' SMART patrol data set. My objectives are;
1. to find relationship between species richness of vascular plants and large mammals
2. to compare distribution of 3 herbivores in different species richness of vascular plants and forest composition (structure, density, canopy coverage, etc.)
Relevant answer
Answer
Hi Myo Min Latt,
the articles below can help (I recommend based on their title and keywords)
Clegg, BW; O'Connor, TG; Manson, AD. (2021) Vegetation classification for the management of large mammalian herbivores: a case study at Mushingashi Conservancy, Central Province, Zambia. AFRICAN JOURNAL OF RANGE & FORAGE SCIENCE DOI: 10.2989/10220119.2020.1827455
Hempson, GP; Archibald, S; Bond, WJ (2015) A continent-wide assessment of the form and intensity of large mammal herbivory in Africa. SCIENCE Vol.: 350, Issue: 6264, pp: 1056-1061. DOI: 10.1126/science.aac7978
Alves, TR; Fonseca, RCB; Engel, VL. (2012) Medium and large sized mammalians and their relation to habitat patches at the Botucatu cuesta, state of Sao Paulo, Brazil. IHERINGIA SERIE ZOOLOGIA 102(2): 150-158.
DOI: 10.1590/S0073-47212012000200006
Reed, KE. (1998) Using large mammal communities to examine ecological and taxonomic structure and predict vegetation in extant and extinct assemblages. PALEOBIOLOGY 24(3): 384-408.
  • asked a question related to Composite Structures
Question
13 answers
Dear All,
Introduction:I am currently conducting parametric studies on Concrete Filled Double Skin Tubes(CFDST) in Abaqus. In case you are not familiar with CFDST, it is a composite structure with an outer steel tube and inner steel tube with a concrete sandwich in between them.
The problem:I am using Abaqus Riks to conduct a parametric studies which involve bending of large tapered cantilever CFDST. I have done validation against smaller scale experimental specimen which are available in the literature. The validation worked very well for me, but when I changed the size of the structure then Abaqus Riks will encounter severe convergence difficulties.
Diagnosis and attempts to solve the problem:I believe the problem is with the interaction between the steel and concrete especially when concrete fails in tension which occurs early in the analysis typically less than 10% of the ultimate load. I have tried numerous things such as modifying the concrete model in tension(e.g. inputting elastoplastic definition of concrete in tension with a small tensile strength), trying different techniques with interactions,changing element and mesh type, changing the solver settings, and I have thoroughly checked the model many times.
I also tried inputting a small value for the viscosity parameter in the Concrete model in Abaqus. This would make the model work, but the results are very wrong where the bending capacity of the structure becomes much larger than it should be.
Preliminary solution: I have decided to eliminate interactions given they are the source of the problems, so I used TIES to model the interface between the steel and concrete. The model worked very well up to failure with no problems. Hence, this verifies that interactions are the source of the problem. TIES imply that there is a perfect bond between the steel and concrete. I believe this is a reasonable assumption because I am mainly interested in the global behaviour of the structure.
Besides, researchers in the past reported that different coefficient of frictions have a minor effect on the prediction capacity CFST and CFDST. Also, EC4 and AISC assume perfect bond when calculating the bending capacity of composite sections. Hence, this justifies assumption of perfect bond is a reasonable assumption which is actually adopted by many researchers simulating reinforced concrete structures.
Conclusion: I appreciate if you can mention any suggestion or solutions to solve this problem. Please note that I am avoiding to use Abaqus/Explicit because it may give inaccurate results for a static analysis due to various issues not to mention the very long time it would take to finish the simulation. Apologies if you found this post long.However, I made it as short as possible to explain this complicated problem which is happening for a really long time. 
Relevant answer
Answer
Sir, is it possible to ask for your model. I am currently modeling it in Abaqus, but having some problems with the interactions.
Here's my email (benjamin.rabangiii@yahoo.com) if it is okay.
  • asked a question related to Composite Structures
Question
11 answers
How composites can be modeled in ANSYS Using Solid185?
 If one try to model a fiber composite layer bonded to a concrete beam for example using solid185 element in ANSY, this layer shall be modeled as volume, since solid185 is a brick element not a shell element. My question is: if thickness of this layer is only 1mm for example; shall we model this layer as a volume with (length x width x 1 mm) dimensions? OR shall we go to (shell section) menu (available in ANSYS) and input the thickness of the layer regardless the thickness of the layer in the modeled volume?  OR shall we use both of them?
Thanks in advance.
Relevant answer
Answer
Thomas Thiesing, yes this is what it means.
  • asked a question related to Composite Structures
Question
6 answers
I am planning to use the Discrete Element Method for propagation of Fracture in Reinforced concrete Structures. Which book would be the best start to study Discrete Element Method from the beginning?
Relevant answer
Answer
  • asked a question related to Composite Structures
Question
18 answers
Currently, I think functional and high filler content polymer nanocomposites are the current trend. Please let me know your thought.
Relevant answer
Answer
Very interesting @Hassan Yousefnia, is that bio-degradable or bio-based materials? What is the source of polymer? Oil-based, plant, or bacteria-enzyme? As for the application, are you aiming for mechanical properties or functional such as anti-oxidant, gas barrier, perfume and so on?
  • asked a question related to Composite Structures
Question
3 answers
Considering two composite beams jointed to each other, for example by bolts, which are under vibration with different frequencies, what is the relation between the temperature value of contact surfaces and loosening between surfaces? By applying more torque on bolts and as a result, more pressure between two contact surfaces, which scenario could be expected: the surfaces' temperature resulted from vibration will increase or decrease?
And, what about the natural frequencies?
Relevant answer
Answer
There are some really good research papers that you can look at for your question. Some of them are listed below
  1. https://core.ac.uk/download/pdf/55628511.pdf
  2. https://ascelibrary.org/doi/10.1061/9780784479742.087
  3. Chapter 3 of https://www.sciencedirect.com/science/article/pii/B9780857094582500031
  • asked a question related to Composite Structures
Question
18 answers
hello every one 
i m working on delamination buckling analysis in abaqus 6.14...
now i want to add geometric imperfection in my model while i m using general static step for buckling analysis ,,,
can any one help me how i can  add geometric imperfection in my model
i don't perform eigen value analysis because i dont need different modes and their buckling load..
i just apply axial displacemnt on two  parts joined by cohesive element with delamination between them....but now i want to add imperfection to it too..i have studied in the abaqus documentation how to add imperfection but that require eigen value analysis,,which i dont want
i just need to know if there is any other way to add imperfection to my model since i m using general static step..
thank u
best regards
Relevant answer
I have created here a youtube channel with many different ABAQUS-tutorials videos on shell buckling:
  • asked a question related to Composite Structures
Question
2 answers
hello dear scholars ,
i am looking for papers proving if abacus has failed crack growth simulation of bonded joints or delamination in composite structures?
my question is concerning the program itself not the model used in the experiment ( CZM, VCCT....)
Relevant answer
Answer
Rajendra Kumar
thank you !
  • asked a question related to Composite Structures
Question
2 answers
Dear community,
for my master’s thesis I’ve been using the "Damage Evolution Law" feature available in ANSYS to calculate the failure behavior of FRP composite structures using FEM simulation. Within the Damage Evolution Law, two different options are available:
- Material Property Degradation
- Continuum Damage Mechanics
Right now I’m trying to figure out on which theoretical approach the two models are based. Could you provide a reference to the research papers in which the respective approaches were developed? Unfortunately, I could not find such a bibliography in either the Theory Reference or the Material Reference.
Many thanks in advance.
Relevant answer
Answer
Thank you for your response. Im looking for a refference papers for both methods and i cant find in the Ansys Manual. Do you know the papers that each of these methods based?
  • asked a question related to Composite Structures
Question
16 answers
Part of the submission process to Composite Structures is to propose potential reviewers for the submitted paper. The reviewers and their contact information will be provided online during the submission. So, is it necessary to include the suggested reviewers in the cover letter with their contact information?
  • asked a question related to Composite Structures
Question
3 answers
I made some impedance measurements under magnetic field to characterize magnetoelectric coupling on BTO-CFO composites. I can determine magnetoelectric coefficient by calculating dE/dH from obtained data.. i just don't know if such coefficient is enough reliable to report it in an article.
  • asked a question related to Composite Structures
Question
6 answers
reviews on plant cell wall structure, composition and function
Relevant answer
Answer
Dear Hasan Kolkas,
I have attached some books and articles about plant cell wall. I hope they would be useful.
  • asked a question related to Composite Structures
Question
8 answers
1. May i know the values for the concrete damaged plasticity in abaqus? it is default value or depends on the concrete properties? btw, where to obtain the values?
2. In the real case, there are the spreader beams on top of the concrete slab as the load inputs. may i know how to input this load in simulation analysis of ABAQUS? it should be assigned as line load/point load/...?
3. how to create the nonlinear result? which module should be used for assigning the nonlinear properties?
i am doing a research on composite structures (steel beam-concrete slab). Thank you for your time.
Relevant answer
Answer
I've made a webtool that should help new users to define these properties. Please find it here:
  • asked a question related to Composite Structures
Question
12 answers
I modeled a composite plate in Geometry module, then meshed in model, but error comes while edit in setup module in ACP. Error box attached here.
Relevant answer
Answer
Du Zhe ANSYS Explicit does not accept any model from ACP pre. You need to use Ls-dyna extension. it is exactly similar to ANSYS explicit and it will accept the ACP pre model (i have tried it for ANSYS 17, not sure about newer version)
  • asked a question related to Composite Structures
Question
11 answers
I am trying to model a composite sandwich structure undergoing a typical drop weight impact test, for my final year project. I have no experience on Abaqus and there is not a lot of help available to me on this software. I have tried to follow YouTube videos to get an understanding of how to use the software; but I still lack the necessary skills.
Does anyone have any links to tutorials that would help me practice impact modelling on composites.
Any help would be greatly appreciated.
Relevant answer
Answer
Hello Matthew,
I strongly believe that you can improve your skills in ABAQUS by using a suitable resource such as book, tutorial video, etc. However, you can use ABAQUS Documentation. There are a great deal of information about how to model in ABAQUS, different elements in this software, different loads, etc. Plus, there are some practical examples in it. You can realize how to apply different loads including static and dynamic loads. You can also find examples to apply the loads of blast, shock and so on as well as examples to model composite materials.
I think that it will absolutely be a good source for the first step. Should you have any questions, please let me know.
  • asked a question related to Composite Structures
Question
2 answers
I have an one question which is :
What is a difference o relationship between layer-wise and zig-zag theories.
Relevant answer
Answer
Dear @Ashish thakur
Thank you ,for explination
  • asked a question related to Composite Structures
Question
2 answers
I have got a publication in which the authors prepared BaFe12O19/CoFe2O4. But the amount / concentration used for preparing the metal nitrate solutions were not mentioned in the publication (except mentioning 'stoichiometric ratio')in Materials and methods section.
Please give your ideas about how to find the weight and concentration of the chemicals used in the synthesis from paper. Attaching the full paper with this question.
Reference:
Yang H, Liu M, Lin Y, Yang Y. Simultaneous enhancements of remanence and (BH) max in BaFe12O19/CoFe2O4 nanocomposite powders. Journal of Alloys and Compounds. 2015 May 15;631:335-9.
Relevant answer
Answer
For example the compound (BaFe12O19) Is composed of one mole of BaO plus 6 moles of Fe2O3 So you can calculate how many gram of BaO you need from its raw material that is Ba(NO3)2 in such case to prepare 100 ml solution contains 1 molar of BaO using the following equation Wt = (M* V * M.wt)/1000
where: Wt = weight of Ba(NO3)2 needed to prepare the one molar solution of BaO
M= Molarity needed for the solution
V= the volume in ml (Cm3) of the solution that is in this example = 100ml
M.Wt= Molecular weight of Ba(NO3)2 and it equals to 261.34
By applying in the equation Wt = (1* 100 * 261.34) / 1000
hence the weight needed from Ba(NO3)2 is equals to 26.34 gram .
By the same way you can calculate the weight of Fe2O3 from its raw material that is here Fe(NO3)3⋅9H2O but remember you will need to prepare 6 molar solution
because the ratio between BaO and Fe2O3 in the compound is 1 : 6 as explained above .
you can apply the above equation to prepare any concentrations of the solution for any compound.
Regards
  • asked a question related to Composite Structures
Question
3 answers
How much dead weight (load/pressure) are used to remove excess resin present in composite structure when using hand layup composite manufacturing techniques small lab.
Relevant answer
Answer
Rokesh Laishram and Rajesh KUMAR Morchhale
Thank you very much for your valuable answers
  • asked a question related to Composite Structures
Question
6 answers
I am looking to start working with the isogeometric method to analyze mechanical behavior such as beam, plate, shell and other structures of complex shapes.
can you help me by giving me simple examples in this method and with articles and books that have explanations and applications?
what do you suggest to me and thank you in advance?
  • asked a question related to Composite Structures
Question
6 answers
CZone add-on in Abaqus 2016 forces the user to use a contact pair interaction (surface-to-surface), rather than a much easier general contact, between my crashbox (composite structure modelled with shell elements) and my barrier (rigid elements).
When I do this I get a strange behaviour and I do not understand where it comes from: the crashbox passes through the rigid barrier, "desintegrating", like in a cheese grater or something.
Any help would be appreciated. The input file and output image attached.
Relevant answer
Answer
Just as a reminder, barrier needs to be the master surface Following the rule of “master the impacted”
  • asked a question related to Composite Structures
Question
2 answers
¿Does the urban development planning takes into account the generation of biological corridors that allow the transit of nativenative and and migratory species and their minimum survival requirements?
Relevant answer
Answer
This is one of many ecological items that must be considered but often neglected in urban planning and design.
  • asked a question related to Composite Structures
Question
10 answers
It is easy to deign a homogeneous 3D model of composite for an structural analysis. 3D models created using SOLID WORKS, CREO etc., are homogeneous models, even 3D models created using powerful FEM packages like ANSYS and ABAQUS are homogeneous possessing homogeneous structural property. What is the best software for creating a heterogeneous composite structure for structural analysis.
Relevant answer
Answer
If you are interested in the microstructure of composites and its effects on permeability, stiffness, etc. etc. it may also be worth taking a look at the GeoDict software at https://www.geodict.com. You will find many publications that use the software in the Showroom -> Scientific publications using GeoDict, Topic Composites section of the web site.
  • asked a question related to Composite Structures
Question
1 answer
it shows an error
1.adaptive meshing is not supported in any elements in this domain.
2.adaptive meshing contraints can be specified on adaptive mesh domain.
Relevant answer
Answer
yes, yo can. However, this demands you to know all the parameters related to ALE and its effect on composite structure first, then you need to translate these parameters to abaqus languge, in other way design model (FE model). After that, specify which parameters need to be constant and which others need to variable.
  • asked a question related to Composite Structures
Question
4 answers
hi
i am working on simulation of air-couple ultrasonic wave propagation into the composite structure in Abaqus and investigate the behavior of delamination in composite.
I was wondering if any one can help me , How can i simulate Air in Abaqus in which i can propagate ultrasonic waves into the model?
also , how can i simulate delamination in composite?
THANK YOU
Relevant answer
Answer
Delamination causes a large reduction in the stiffness. So, you can model delamination by reducing the stiffness of the defected region. Elastic modulus in the delaminated region can be 70% or 80% less than the actual modulus of the composite material. This is one way to simulate delamination using material properties. Other way is through the mesh design in FE modeling... you should read some papers on delamination detection in composite structures.
  • asked a question related to Composite Structures
Question
10 answers
Which popular material used in the construction industry is a composite?
Relevant answer
Answer
Agree with Jamik Sohounhloue
  • asked a question related to Composite Structures
Question
8 answers
I am working on dyes removal from aqueous solution by using LDH. already there are alot of LDHs used regarding to this application. I want to bring novality by changing the structure and composition of LDH.
Relevant answer
Answer
Salima Bouteraa Any of the Rare Earth (RE) metals can be tried except Pm (which is radioactive). Some are expensive, like Dy/Tb etc---Heavy RE.
Ce and La largely behave similarly in my alloys. It is better to try relatively different elements in the beginning.
  • asked a question related to Composite Structures
Question
7 answers
'Hello Everyone ,
Hope you are doing fine . I am a graduate student and I have not much idea of the scientific journals .
Can you suggest me some authentic journals where I could submit my work related to composite's structural (numerical investigation of buckling behavior) . The work is pure simulation based .
As I am a student I would really appreciate a journal with minimum to zero submission fee .
Best Regards
Aamir
Relevant answer
Answer
Hi Aamir,
In addition to Amrit's comment, I would add:
In addition to the ACI struct. J.
Regards!
  • asked a question related to Composite Structures
Question
4 answers
I am searching for a good topic in Dynamic RAM for my research practice/project in VLSI Design domain. I want to work on outer peripheral circuitry for low power applications (Not into device level i.e structure and composition ).
Relevant answer
Dear Hitesh,
welcome,
If you want to work with DRAM then the best way to get the state of the art and the challenges in advancing the DRAM is to read the review papers in the DRAM.
I think as a cmos technology device it will suffer with scaling down the transistors. So, i think you can work on scaled DRAM and its subsystem circuits as the sense amplifier and the decoder. In any case you will get experience in designing VLSI circuits.
You may look at the link to get more information:http://www.ijircce.com/upload/2015/september/106_A%20Literature.pdf
  • asked a question related to Composite Structures
Question
5 answers
I am doing buckling analysis of laminated composite shells with different cutouts under axial compression in abaqus . As a shell has different type of geometrical imperfection how can I introduce them separately in abaqus ?
Relevant answer
Answer
You can do that by modifying the coordinates of the points in the input file.
  • asked a question related to Composite Structures
Question
4 answers
I would like to ask you about a problem I have encountered. How could I define the elastic modulus in radial direction in terms of rectilinear orthotropic properties such as Ex and Ey. Similarly, I would like to write Etheta in terms of Ex, Ey and theta. Is there a way to transform rectilinear material properties into polar orthotropy ?
Relevant answer
Answer
Hooke's law for an orthotropic plate takes the form εij=sijklσkl (i,j,k,l=1,2). The nonzero components of compliance tensor s in an orthonormal coordinate system xy (provided that x and y are principal directions of orthotropy and using “tecnical” notations) are:
s1111=Ex-1, s2222=Ey-1, s1122=-vyx Ey-1, s2211=-vxyEx-1, ( due to symmetry s2211=s1122, s1212=s2121=(2G)-1,
where Ex, Ey are the Young's moduli along axis x and y, G is the shear modulus, vxy is the Poisson's ratio that corresponds to a contraction in direction y when an extension is applied in direction x (and vice versa). Components of tensor s in polar system can be found as s’íjkl=aipajqaksaltspqst, where a is orthogonal rotation tensor with components a11=a22=cosΘ , a12=-a21=sinΘ , Θ is polar angle.
In particular,
s’1111=Er-1=Ex-1cos4Θ+(G-1-2vxy Ex-1)sin2Θ cos2Θ+Ey-1sin4Θ ,
s’2222=EΘ-1=Ey-1cos4Θ+(G-1-2vxy Ex-1)sin2Θ cos2Θ+Ex-1sin4Θ.
  • asked a question related to Composite Structures
Question
2 answers
papers on petrographic, structural and physical properties of volcanic glass.
Relevant answer
Dear Sir
Attached is a research about your question.
  • asked a question related to Composite Structures
Question
6 answers
As part of my research for my PhD project, I wish to produce a FEA model of a bi-stable composite structure with piezoelectric transducers attached to the surface of the structure and optimize the system for maximum power output under certain dynamic load cases.
I am attempting to create the FEA model in ABAQUS. I understand the software doesn't provide a direct way to model a full electro-mechanical system (simulation of electrical circuit attached to piezoelectric transducers), unlike ANSYS, and so I would like to know whether a method exists to model a full electro-mechanical system in ABAQUS? If so, how is this method implemented?
  • asked a question related to Composite Structures
Question
17 answers
It is about the types on nano particles that used in order to reinforcement of composite structures
Relevant answer
Nicolaus Probst
Dear Sir
Thanks so much for this details
  • asked a question related to Composite Structures
Question
7 answers
Hello Everyone,
I need to modify and make a change for the composite materials and make it act in a different behavior so i am asking if anyone have/ or know a published data for the composite structures experimental set up in details! Just tell and i really appreciate your time you gave to me.
Thanks in advance
Relevant answer
Answer
I think there is.
  • asked a question related to Composite Structures
Question
4 answers
I want to start working on the generalized differential quadrature (GDQ) method to solve the problem of the mechanical behavior of beams, plates and shells.
Dear colleagues, I hope to give some suggestions (papers, books, etc.) and simple examples for work on this method.
  • asked a question related to Composite Structures
Question
4 answers
I want to start working on the generalized differential quadrature (GDQ) method to solve the problem of the mechanical behavior of the beams, the plates and the shells.
Dear colleagues , I hope to give some suggestions (papers, books, etc.) and simple examples for work on this method.
  • asked a question related to Composite Structures
Question
3 answers
Kindlya can any one tell me
it is possible to use the same laws of thin metallic structures
for the composite material
Relevant answer
Answer
Can you share what actually you want to do with composite ? What you want to refer here by -" laws of thin structures " ?
  • asked a question related to Composite Structures
Question
4 answers
I am trying to model a composite material with periodic microstructure. I am trying to use the approach presented by Feyel (FE2 multiscale). it seems however a bit challenging to write a MATLAB code for the periodic homogenization theory (There is also no available codes). Therefore, I am seeking an initial guide to write a MATLAB code addresses my composite structure.
Thanks in advance!
Relevant answer
Answer
Hi Hessein,
I think there are many plugins available for homogenization, both commercial and for free. I have used HOMTOOLS, a free Abaqus plugin developed by Stéphane Lejeunes and Stéphane Bourgeois and am very happy with it. The plugin together with documentation can be downloaded for free from their website:
In the website you can also find some tutorials are shown.
  • asked a question related to Composite Structures
Question
37 answers
My question is, should´nt the load induction lenght be in function of load conditions and not the geometric properties.
I am not an expert on this particular topic, so does anybody knows the theory of this load induction lenght or where can i find documentation about it.
Relevant answer
Answer
Following..
  • asked a question related to Composite Structures
Question
8 answers
I have 3 4th order non-linear Partial Differential Equations with three dependent variables and 2 independent variables. I have boundary conditions for 2 dependent variables. The problem is formulated when analysing a laminated composite structure. It is a steady-state analysis. Should I proceed with Navier's method/FEM/ or some other approach? I would appreciate suggestions. Thank you.
  • asked a question related to Composite Structures
Question
6 answers
I have modeled a steel-concrete composite box girder in ABAQUS using following element type:
Steel box girder- S4R, Shear Connector(Stud)- C3D8R, Concrete Slab- C3D8R, reinforcement- T3D2
I have considered elastic and plastic behavior of both steel and concrete(CDP). While comparing load-deflection curve from both experiment and FEA, it has given me pretty much accurate value for ultimate load. However, the elastic response of the structure is much more stiffer from experiment data. I have already updated the FE model based on constructed specimen such as thickness of steel plate, steel & concrete strength. What could be the problem?
Relevant answer
Answer
You may find the answer of your question in the attached file.
Best regards