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# Finite Element Method - Science method

Discussion forum about Finite Element Method and its applications

Questions related to Finite Element Method

I have Force-Displacement values of a tensile test that undergoes uniaxial loading. Please find attached the stress strain curve of the loading.

Sigma1 denotes the Equivalent stress of the element at current time increment and Sigma0 denotes Peak equivalent stress of the element reached at the end of the loading stage. I need to calculate a stress ratio Sigma1/Sigma0 at each time increment.

In order to calculate the stress ratio, the time increment of the peak stress has to be reached after which the field variables (of USDFLD) in the previous time increments has to be modified to calculate the stress ratio. This stress ratio has to be applied to the material model of the same simulation.

Is it possible/recommended to achieve this using USDFLD? Or is there a better alternative in ABAQUS?

Hello dear colleagues

Hope you're fine.

I'm trying to model a threaded connection with a 2D axisymmetric model.

I need to make several models with slight changes and differences.

In some models, once the job is submitted, before the analysis gets started, it gets aborted due to "some nodes have Negative coordinate values" error.

When I check the error node set, they are all placed on the axis of symmetry.

I tried several ideas to work this out but none of them was successful like:

>changing element type,

>constraining the part in the direction prependicular to the axis of symmetry

>Using another datumn coordinate system

I appreciate it if you have any ideas to fix this error.

PS: some other models get solved without this error while these models are copied from one another and I couldn't see any difference seem to be related to this error between them

dear friends

I was trying to study problems with finite friction involving indentation of a thin layer bonded on a substrate. As you can see from the theory

there are large differences between frictionless and infinite friction cases both at punch/layer and layer/substrate interface. However, particularly for incompressible materials, in ANSYS the contact results with finite friction are unreliable and I gave up in trying to setup contact stiffness parameters to find reasonable results --- here we know analytically some limit behaviour for frictionless and very high friction results, so we can check the intermediate case.

Do you think other FEM code could do better? To setup the mesh for the flat punch is extremely simple, so we could try with your help in other codes.

thanks

Mike

For the evaluation of saturation profile , i will do simulation of flood flow in the SEEP/W. For different depths of flood head at varing time, which type of analysis and how the flood head versus time function is collaborated in boundary conditions?

Hello,

I would like to compute de the stress tensor of a Timoshenko beam at its Gauss points, to be able to implement an elastoplastic law in my finite element calculations.

Firstly,I know the displacement field at any point of my beam thanks to the relation u(x) = N(x) U, where U is the matrix of degrees of freedom at the nodes of my beam tU = (ux1, uy1 , uz1, θx1, θy1, θz1, ux2, uy2, uz2, θx2, θy2, θz2)

Then, I took as an expression of N the form given in this article https://www.researchgate.net/publication/236659875_Shape_functions_of_three-dimensional_Timoshenko_beam_element#fullTextFileContent , which corresponds to a Timoshenko model.

I deduce the deformations for small strains with ε = 1/2 (grad(u) +tgrad(u)), I obtained the equation shown in the picture.

I then apply Hooke's law to find the stress.

I then obtain that for a traction test (ux2 = constant, the other components of U are zero), the displacement field and the strain tensor are constant on my beam in particular along a cross-section, with only εxx non-zero, on the other hand the stress tensor has non-zero components other than σxx.

I conclude that my model shows that the cross sections are non-deformable, with therefore additional "virtual" forces, which prevent the beam subjected to traction along x, from being refined along y and z in accordance with the Poisson effect . On the other hand, I would like to have a "natural" behavior where the beam is refined according to y and z.

Do you have any articles for this?

Thanks a lot

We use our vectorized Q1 FEM codes (in Matlab) in 3D to simulate elastoplasticity in small strains. It would be beneficial to reduce the number of 8 Gauss integration points to push our computational limits. I understand there will be an extra addition to the stiffness matrix if we reduce the number of integration points to 1 for instance. Can anyone provide me with a good description of how to implement it? Thank you in advance.

Dear amazing members,

I have a doubt.

If I have three adjacent planes with different boundary conditions, in a 3D domain, Dirichlet (fixed temperature) on one plane, Neumann fixed flux on another plane and Neumann heat conduction on another, then what should I do?

Should I consider all the conditions on the common node? I read somewhere that if Temperature and heat flux is specified on a node then only specified temperature should be considered, but I don't know if I should ignore convective heat transfer when temperature is specified.

And in 2D case, when only temperature is specified on one edge, and convective heat transfer on adjacent edge? Then should I consider the heat convection at the common node these two edges?

Thank you 😊

I would like to develop 2D open cell foam models which can be further used in the FE modelling. Could anyone please suggest any modelling tool?

Thank you

Dear all, I am trying to compute the Modified Weak Galerkin method for the Poisson Problem mentioned in the paper:

[1] A modified weak Galerkin finite element method. X. Wang, N.S. Malluwawadu, F. Gao, T.C. McMillan.

I am using FreeFEM++, but there are difficulties in applying the algorithm (3) mentioned in the paper above, where the jump function, the average function, and the weak gradient are not used or defined by anyone before in this program.

My question is, which software program should I use to compute this problem?

Dear all,
I am trying to compute the Modified Weak Galerkin method for the Poisson Problem mentioned in the paper:

[1] A modified weak Galerkin finite element method. X. Wang, N.S. Malluwawadu, F. Gao, T.C. McMillan.

I am using FreeFEM++, but there are difficulties in applying the algorithm (3) mentioned in the paper above, where the jump function, the average function, and the weak gradient are not used or defined by anyone before in this program.

My question is, which software program should I use to compute this problem?

ABAQUS ERROR: ONE OF THE ELEMENT IS CLOSE TO PARALLEL WITH ITS BEAM SECTION AXIS, so I'd like to know how to solve this problem? The element property is beam element, so I should define the section oritention in all elements.

Below you can find equetion which express flow curve which describes the plastic deformation behavior of a material in a uniaxial tensile (or compression) test. I looking for books, articles which gives me information how values of C and n depends on geometry (eg. diamater and wallthicknes of drawn tube) as well as initial mechanical properties, before material work hardening. Do wires and rods of the same material but with different dimensions have a different form of the flow-curve, or does it depend only on the initial properties of the material?

How to add missing citation at Research gate?

Cited article:

Conference Paper Symbolic-Numerical Solution of Boundary-Value Problems with ...

citing article:

ref. 4

How to do quasi static compression test (2mm/min) in ansys Workbench? Please help me

Finite element method will be used to determine the stress-strain of a 3D composite material made structure.

I want to compute the critical load of the Euler-Bernoulli Beam equation by applying axial load. I am using the finite element method for discretization and the eigenvalue method to compute critical load. You can see more detail in the attachment. But I did not get an accurate value compared to the analytical value. If anybody has an idea about that please tell me. I will be very thankful.

Best,

Rauf.

Dear Researchers :

I will very much appreciate the help.

I have a 2D model in COMSOL. It's a plate, made of Polyethylene. An AC Voltage is applied on the upper electrode, the lower electrode is on V=0 (ground)

The sinusoidal function of the voltage is : Vo*Sin[wt + phi] where phi = 0 and V_o is equal to 2.4 kV

I am attaching an image of my 2D Geometry

I am solving the model in two steps

Step 1 : Using a Time Dependent Study (just to solve the physics of the electric currents module)

Step 2 : A stationary solver, to solve the Heat Transfer in Solids part.

I used the Multiphysics interphase of Electromagnetic Heating

I can correctly solve the Electric part of the model

But for the temperature, this is the graph that I get, which of course is not correct

Does someone might know where the mistake might be ?

Best Regards all :)

Hello everyone,

I am currently investigating the phenomenon known as the Indentation Size Effect (ISE) using the Finite Element Method (FEM). My research involves conducting indentation tests through simulation using ABAQUS.

Here are some specifications of the model:

- It is a 2D axisymmetric model.
- The indenter is represented as a rigid body and possesses a semi-angle of 70.3°.
- The specimen material is assumed to be homogeneous and isotropic, characterized by an ideal elastoplastic model.
- Mesh is refined near the indenter tip to capture stress concentration accurately.
- Contact Interaction: Surface-to-surface contact, Tangential behaviour - Frictionless, Normal behaviour - Hard Contact.

I have conducted simulations at various depths, ranging from 500 nm to 5000 nm. To determine the hardness, I have employed the Oliver-Pharr Method. According to the concept of ISE, the hardness should decrease as the indentation depth or load increases. However, in my results, I have observed that the hardness remains almost constant regardless of the depth. Consequently, I am unable to observe the anticipated trend associated with the Indentation Size Effect in my findings.

For your convenience, I have attached the .cae file and the hardness vs indentation depth plot.

I would greatly appreciate any assistance or insights you can provide to help me address this issue.

Thank you all in advance.

I'm struggling to obtain the right behavior of gfrp bars, in the process of validating my model i achieve a bilinear behavior in the displacement x force graph when using gfrp bars as reinforcement, but in the research that i'm using the experimental behavior was linear. Even though i've tried to change a lot of parameters in my model I still couldn't obtain something close.

The model has steel stirrups and upper layer reinforcement and only the lower reinforcement uses GFRP bars.

The bars were modeled as wire T3D2 and the beam as solid c3d8r

For the properties data:

For concrete i'm using de young's modulus, poisson and CDP

For GFRP bars young's modulus, poisson and tensile strenght also rupture strenght

Anyone knows what can i do to correct the behavior that i'm having?

In the image i show the behavior that i need in black and what i am obtaining in the other colors

Dear colleagues

I'm modeling bone healing around dental implants using Abaqus subroutines (UMAT / USDFLD).

I wonder:

1. How SDVs of

**current and previous increment**can be accessed in the current increment through**UMAT**?2. and how SDVs of

**previous increments**(eg. 10 previous increments) can be accessed in the current increment through**USDFLD**?Thanks in advance,

Yunus.

PS: The value of SDVs at the beginning of the current increment can be accessed by GETVRM utility routine in USDFLD

Could any one provide me with a MATLAB code for fixed-fixed beam that calculates the Mass and Stiffness matrices, Natural frequency, and mode shapes.

Hello dear colleagues

hope you're fine.

I wonder if there is a way to average a field output (eg. Von mises stress) in last 10 increments for each element using:

a. Abaqus subroutines

b. Abaqus python scripting

c. any other way

Thanks in advance,

Yunus.

The following approaches are being used for modeling fractured porous media with multiscale and multiphysics:

1)projection-based embedded discrete fracture model (pEDFM) with cell-centered finite volumes. Check DOI:10.3390/en16020928 and DOI:10.48550/arXiv.2302.10986

2) A combined eXtended Finite Element Method (XFEM) and Embedded Discrete Fracture Method (EDFM). Check DOI:10.1016/j.geoen.2023.211984 and DOI:10.1016/j.jclepro.2023.137630 and DOI:10.1002/essoar.10509306.1

3)Mixed Multiscale Finite Element Method. Check DOI:10.1029/2020WR028877 and DOI:10.1016/j.jcp.2023.112134

4)TOUGH-FLAC simulator. It links TOUGH2, an integral finite difference multiphase flow and heat transport simulator, and FLAC3D, a finite-difference geomechanical code. Check DOI:10.1016/j.compgeo.2022.105161 and DOI:10.1016/j.ijrmms.2021.104872

For a comparison of different approaches check: DOI:10.48550/arXiv.2302.10986

Which one do you prefer and why?

is there any other approach?

I want to write a code related to the flutter of aeroelastic wing under unsteady load using doublet lattice method (DLM). I want a good reference with numerical examples or a book which learn me coupling doublet lattice method (DLM) with finite element method (FEM) step by step.

Hello everyone,

I have a problem calculating the modal assurance criterion (MAC) of a experimental mode shape and a FEM mode shape. I can calculate the AutoMAC for each mode shape, for which the values are all correct. Both matrices show that the same mode shape gets a value of 1, while the rest is near 0.

However if I now apply the same formula to the normal MAC nothing seems right. The sensors for the experimental mode shape can measure displacement in one DOF. So at each node the displacement is a complex value in the direction of one of the local X, Y or Z-axis. The FEM mode shape contains real values at each node and the displacement can occur in all 3 DOFs.

I hope someone can help me resolve this problem.

Thanks in advance!

There is no doubt about the equivalence between the dynamic stiffness method and the finite element method. However, there are currently many extensions of this equivalence in Euler beam theory, and Taylor element expansion of the dynamic stiffness matrix can improve the accuracy of finite element analysis. Can the Taylor expansion of the dynamic stiffness matrix elements be achieved for Timoshenko beam theory? Do you currently have any relevant research work? Seeking recommendation and cooperation.

Explicit scheme : By varying the mesh size, we see that for smaller sizes, the computation time for the usual mass matrix (not diagonal) exceeds that of the lumped mass matrix (diagonal). This I understand. But when the mesh size becomes large the computation time for the lumped mass matrix (diagonal) exceeds that of the usual mass matrix (not diagonal). Why ?

it is a question of solving an equation by the method of the elements. I was able to find the solution on pdeMatlab. but the one if does not coincide with the one generated by my script.

Hello All,

I am working on calculation of differential settlements for embankments which are subjected to railway loadings.

can you please let me know how to activate railway loading in PLAXIS or in any other FEM software?

Regards,

Jayatheja M

I want to construct the basis functions for P and Q elements

Hi all,

I am trying to determine the relative motion between two surfaces in contact. Although I know how to calculate the relative motion, I don't know how to extract the paired nodes (closest nodes) of surfaces in ABAQUS when my geometry of study is undeformed.

For relative motion I will be using the following formula:

If there are contact surfaces named A and B, where there are i-th number of nodes:

**X - Relative motion**: square root( ( (X Deformed Node1B - X Deformed Node 1A) - (X Undeformed Node1B - X Undeformed Node 1A) )^2 )

**Y - Relative motion**: square root( ( (Y Deformed Node1B - Y Deformed Node 1A) - (Y Undeformed Node1B - Y Undeformed Node 1A) )^2 )

**Z - Relative motion**: square root( ( (Z Deformed Node1B - Z Deformed Node 1A) - (Z Undeformed Node1B - Z Undeformed Node 1A) )^2 )

**Total relative motion**: square root ( (X - Relative motion)^2 + (Y- Relative motion)^2 + (Z - Relative motion)^2 )

Please let me know if I can make my question more understandable or if there's more information required to make it clearer.

Noting that i'm using 4 nodes quadrilaterlal linear elements and i have nodal displacements.

Hi,

I would like to apply a defined value of initial stress on 3D Shell elements in the initial step in Abaqus CAE. These shell elements are connected to a 3D Deformable Solid by a Tie Constrain. I have also tried to connect them through "

*shell-to-solid-coupling*" constrain, but the same result. After the initial step, I provided a self-equilibrium step without any loading (**Figure 4**).My problem is that after the next steps when loading starts a fast relaxation of this shell element (

**Figure 1**) occurs without transferring the stresses to the tied 3D Solid shape (**Figure 2**). The tie properties are as shown in**Figure 3**.My question is how to transfer a prestressing load (predefined field: stress) from a shell element to a 3D Solid, tied to each other since the main reason for this prestressing is to provide a negative deflection in the main structure?

Dear colleagues,

It is commonly accepted that the total deflection Vt in a 4PB bending test consists of two parts: 1) Deflection Vb due to pure bending and 2) Deflection Vs due to shear forces. The last one doesn’t contribute to the occurring strain in the beam. Regarding the present devices and the dimensions of the beam, the ratio of Vs/Vb in the center of the beam for pseudo-static bending (up to 10 Hz) is given by: Vs/Vb = [4.(1+n).H

^{2}]/[As(3.L^{2 }-4.A^{2})]. in which H is the height [m] and L is the effective length [m] of the beam; A is the distance between the outer and inner support (and not the distance between the two inner supports). For 99% of the present 4PB devices, A is equal to L/3 and thus in value equal to the parameter a which is used for the distance between the two inner supports. The parameter As is the so-called shear coefficient (in some papers denoted as β).G.R. Cowper has done a lot of research work in determining a formula for the calculation of the shear coefficient (see Wikipedia “Timoshenko-Ehrenfest beam theory”). For the prismatic beam, Cowper gives the formula a = 10(1+n)/(12+11n) in which n is the Poisson ratio of the beam material. The formulas given in Wikipedia are all based on bending the object

**without touching or grabbing the beam.**The theoretical approach to the problem is quite correct, but in reality, one has to touch the object to bend it. This touching (the point loads at the inner supports) has an influence on the value of the shear coefficient. For a prismatic beam, the shear coefficient according to Cowper is 0.8517. Using a 3D FEM model in which the beam was bent without touching it (a shear stress distribution at the inner supports was used for bending the beam) a value of 0,8588 was obtained. When the beam in the 3D FEM model was bent using line loads at the inner supports a value of 0.85 was calculated. In these calculations, the clamping forces were taken nil.I use the value of 0.85 in processing 4PB data. Of course, I admit the influence of Vs is small but should not be ignored. And if the forces used for clamping the beam are too high this can also influence the value of the shear coefficient.

Hello all,

I need to find residual stress profile of a target structure after the shot peening process. I created FEM model in ABAQUS Explicit. My question is how to obtain the residual stress after impact? Is it directly one of the stress outputs, like S11? Thank you.

Good day to everyone,

I have designed a scaffold which is made up of a plastic material. I wanted to do a compression simulation for the same. I would like to know which model should I consider in my physics for this plastic-based scaffold.

Many thanks.

Regards

Rajkumar

IIT Kanpur, India

I am doing the project in inverse finite element method(iFEM).

I am trying to find some good material to understand the concept of inverse finite element method (iFEM) for structure. Need suggestion.

Also, I need a help to develop the MATLAB coding for inverse finite element method (iFEM).

please kindly help me

Dear community members,

I am using FEM to solve heat conduction equation. In 2D rectangular domain, there are four boundaries, and at two adjecent boundries, temperature is specified (Dirichlet boundary condition).

For eg. T_a = 30 °C on boundary A, and T_b = 50°C on boundary B. There is a common node which is shared by both boundaries A and B.

I want to know that should be the value of the temperature at this common node, 30°C or 50°C or something else? Please share your knowledge or any reference will be very helpful.

Thanking you.

Dear sir or ma'am,

I am solving a 3D heat conduction equation involving a moving heat source (a laser). The goal is to get the thermal behaviour of the domain with time.

I am using structured grid and using the element size less than the dia of laser spot, which is way too small. It is computationally very heavy for my small laptop.

There is a method which uses adaptive moving mesh. A finer mesh surrounds the laser spot as it moves. But I do not have any idea how to implement that in my code.

Could you please recommed any thing where I can start? or how should I proceed?

Thank you and regards,

Ravi Varma

Dear friends,

i am doing the project in inverse finite element method(iFEM).

I am trying to find some good material to understand the concept of inverse finite element method (iFEM) for structure. Need suggestion.

Also I need a help to develop the MATLAB coding for inverse finite element method (iFEM).

please kindly help me

looking positive information

Can someone guide me on the following:-

1. References I can use for ISHDT using the FEM method.

2. Stress computation process for Composite laminates.

As far my understanding, formulation of custom elements is needed. For example, Spectral elements method requires very high order element.

My question is, do people do this by hand or use any software tool?

Thanks.

Hi

I am trying to model a poro-hyperelastic material, but the problem is, this kind of physics is not present in any of the FEM software including COMSOL or ABAQUS,the comsol have a module only for poro-linear elasticity, but there are few papers on its modelling and they are using subroutine for that.

please help

I am attempting to model a pretensioned concrete beam in ansys by varying prestressing force along the Straight Pre-Tensioning Strand.

During the experiment, the beam was fabricated segment by segment. The applied prestress was then released decrementally after each concrete segment.

The results of the distribution of prestress should be similar to the attached Figure 1.

However, in the finite model, the beam model is already been fully constructed.

I am trying to consider the prestressing force as push in pressure at the both ends of the strand.

Hence:

How do vary the pretensioning force for each concrete segment ?

If possible, please help me to provide some background source.

Thanks

Hello,

I am rather new to the computer aided engineering & design domains and are currently learning the basic techniques how to model, simulate and post-process a model. I learned that the typical pipeline seems to be modelling in CAD -> generating Tet-Mesh -> Simulation using FEM -> Post Process. For design changes, the pipeline is repeated.

Recently, I stumbled across the isogeometric analysis (IGA) method initially proposed by Hughes et al. [1] in 2005, which allows for FEM-like simulation in CAD. This relieves engineers from meshing that can account for up to 80% of development time [2] and shortens the design pipeline/cycle.

Now, many years have passed since 2005 but still the workhorse of computational engineering projects seems to be the FEM. So, I am curious why is IGA not more common in the industry, while it has so much potential? In order to better understand why the situation still is what it is, I would like to read about your opinions.

Lets boil it down to 2 questions:

1) Why is the IGA not more common in the industry?

2) Is the IGA eventually going to replace the FEM?

I would very much appreciate to read about your experiences and opinions :)

Best regards,

Daniel

[1] HUGHES, Thomas JR; COTTRELL, John A.; BAZILEVS, Yuri. Isogeometric analysis: CAD, finite elements, NURBS, exact geometry and mesh refinement. Computer methods in applied mechanics and engineering, 2005, 194. Jg., Nr. 39-41, S. 4135-4195.

[2] COTTRELL, J. Austin; HUGHES, Thomas JR; BAZILEVS, Yuri. Isogeometric analysis: toward integration of CAD and FEA. John Wiley & Sons, 2009.

Hello. I am working on a project that investigates the stresses in severe scoliosis. Unfortunately, severe scoliosis has not been studied much using FEM. Can you help me to find the suitable

**Loading**and**Torque**for the situation when the cobb angle is**greater than 40 degrees**? Or to Recommend me an article that has good information in this field.Thank you so much for your attention and participation.

Hi,

Is it necessary to simulate the unit-cell using FEM (HFSS, CST), its dimensions should be less than a wavelength?

In other words, there is no dimensional limitation of the structure in the simulation of the unit-cell?

My problem is that the simulation for a periodic antenna structure does not converge.

Help i am getting the following error message in abaqus

**WARNING: Surf-1 is ambiguously connected at node ###.
This surface cannot be used with *CONTACT PAIR.
***ERROR: 1 improperly defined surface(s). Please check your surface
definitions. Make sure that all surface normals point outward.

Note:

The mesh is an orphan mesh and is generated outside ABAQUS.

The mesh is fine and has a huge number of elements.

Element typr for the mesh is C3D4

i have defined the surface using ABAQUS CAE and it was generated automatically using the following commands

*elset, elset=surf-1-S1-1

*elset, elset=surf-1-S2-1

*elset, elset=surf-1-S3-1

*elset, elset=surf-1-S4-1

....

*surface,type=element,name=surf-1

surf-1-S1-1,S1

surf-1-S2-1,S2

surf-1-S3-1,S3

surf-1-S4-1,S4

As you will see, i have followed section

**2.3.2 Element-based surface definition in abaqus user's guide.****if you read "**Creating surface facets by specifying solid, continuum shell, and cohesive element faces" you will see i have followed it.

So what is the issue here?

I am interested to the discontinuous Galerkin in my research, but after my modest research, I found two type of it Modal DG and Nodal DG. I wanted to know :

how effective is each one of them ?

What is the difference between them ?

I have created a solid mesh of a flange model in hypermesh. However, only one of the mesh quality criteria is not satisfied. The max angle of some hexahendral elements is slightly higher than 135° (136°). How can this affect the final results?

Note: aspect ratio, jacobian, warping angle,skewness are fine

solving third order and up of PDEs.using Comsol

If there is 2 DOF (Translational, Rotational) Cantilever beam, and it has 7 elements, I want to use System reduction technique to get rid of the rotational Dof, Do I expect to obtain the same first seven natural frequencies?

Because I tried to use SEREP technique and I did not get the first seven natural frequencies, I got the 1,3,5,7,9,11,13 natural frequencies?

Does anyone has explanations please?

I modeled Lamb waves propagating in a carbon fiber composite plate by using the semi-analytic finite element method and solved the partial differential equation by using COMSOL PDE module. The Dispersion curve was consistent with that calculated by the "Dispersion Calculator". However, when I got the through thickness profiles obtained by the two methods, they were completely different. I don't know what is the cause of this problem?

FEM modelling software such as ANSYS, MATLAB, OpenSees, and Abaqus are available. Similarly, I'm looking for FEM software that could be used to analyze air pollutant dispersion. Is there anything such as this available?

Greetings researchers!

I am using FEM to obtain the time response of the nonlinear forced vibration of plates. I am using plate elements based on Reddy's HSDT and Newmark time integration in conjunction with the Newton-Raphson iteration to obtain the time response.

It is well known that multiple steady-state solutions can exist in the case of nonlinear forced vibrations. Also, all steady-state solutions are not stable.

*In practice, unstable solutions are not realizable and the system assumes any one of the stable solutions depending on the initial conditions.*I was curious to know

*whether the FEM predicts only stable steady-state solutions. Or does it predict stable and unstable solutions and the stability of the predicted solutions needs to be determined through other means?*Thank you for your valuable time.

With best regards,

Jatin

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.

I am working on an implant meant for a mandible defect. When simulating the load case, the parts will always penetrate each other. There is a deformation scale factor of 90, so the penetration wouldn't happen if the factor was 1 because there is hardly any motion.

Should I even care about the penetration if it doesn't occur at a scale factor of 1?

If I do, how to prevent this from happening?

The interaction properties I am using are tangential behaviour (frictionless) and normal behaviour ("hard" contact, default constraint enforcement method). I applied them as General Contact in one model and as Surface-to-Surface-Contact in another model.

Thanks in advance!

I was using bilinear interpolation for a PPPM (particle-particle-particle-mesh) on a FEM mesh but I think it is not valuable enough. So my question is: ¿ Do you know any algorithm for mesh point-particle interpolation on a Finite element mesh (for quadratic node elements actually).

Hi everyone,
So i have an orphan mesh of a composite material, i want to duplicate it couple of time side by side so it would work together.
I have tried the option "copy mesh patterns" but couldn't do it because it says it has no boundaries!
Any suggestion how to solve this issue?

I'm looking to use deformation obtained from FEM calculations as inputs to the MD simulation run by LAMMPS and cycle back the stresses from LAMMPS to deform the FEM geometry.

Does anyone have experience with this?

Recently I'm working on crack simulation in modal analysis using ANSYS APDL.

The process is essentially to solve a static problem in the first step, then solve a modal analysis problem based on the results in the first step (with prestress effect on).

In the first step I used XFEM to model the crack. The static problem is solved successfully. When I was trying to do the modal analysis, I got this error:

**An unexpected error ( SIG$SEGV ) has occurred... ANSYS internal data**

**has been corrupted. ANSYS is unable to recover and will terminate.**

**Previously saved files are unaffected. Please send the data leading**

**to this operation to your technical support provider, as this will**

**allow ANSYS, Inc to improve the program.**

Does this mean XFEM is not applicable to modal analysis in ANSYS?

Hello everyone,

Some discretizations of pressure-displacement formulation in Biot poroelasticity produce spurious pressure oscillations in some cases, for example, for small time step sizes. If I understood correctly, FVM for flow and P1-FEM for mechanics fall in this category. How does one rigorously prove existence of such instability? Is it possible to obtain any estimates on time step size for instability to occur? I guess this analysis can be carried out in FEM framework in some way.

Thanks in advance!

I have submitted a job in ABAQUS 2020 with a model of padeye being pulled in one side. The status in abaqus is:

The job "SpreaderV1" has been created.

The job input file "SpreaderV1.inp" has been submitted for analysis.

Job SpreaderV1: Analysis Input File Processor completed successfully.

But after almost an hour the solving process is not started yet.

I am using ABAQUS 2020, because in ABAQUS 6.14 I got error code 1073741795. It might have something to do with my processor.

My PC specification is:

AMD Ryzen 5 5600H (6 Core, 12 threads, 3.5 GHz)

RAM 16 Gb 3200.

Or maybe Abaqus is not optimized to run with AMD processor? I think the processor computing ability is not the problem since overall Ryzen 5 5600H is better than many gen 11th intel processor

I can run simple job like simple box with surface load, truss analysis, etc just fine (with 6.14 and with 2020 ver). Maybe ABAQUS (both for 6.14 and 2020 needs some tweak to run fine with AMD). I have uninstalled the 6.14 ver

I have submitted a job in ABAQUS 2020 with a model of padeye being pulled in one side. The status in abaqus is:

The job "SpreaderV1" has been created.

The job input file "SpreaderV1.inp" has been submitted for analysis.

Job SpreaderV1: Analysis Input File Processor completed successfully.

But after almost an hour the solving process is not started yet.

I am using ABAQUS 2020, because in ABAQUS 6.14 I got error code 1073741795. It might have something to do with my processor.

My PC specification is:

AMD Ryzen 5 5600H (6 Core, 12 threads, 3.5 GHz)

RAM 16 Gb 3200.

Or maybe Abaqus is not optimized to run with AMD processor? I think the processor computing ability is not the problem since overall Ryzen 5 5600H is better than many gen 11th intel processor

I can run simple job like simple box with surface load, truss analysis, etc just fine (with 6.14 and with 2020 ver). Maybe ABAQUS (both for 6.14 and 2020 needs some tweak to run fine with AMD). I have uninstalled the 6.14 ver