I've got some residual stress measurements in a structure and I would like to know if there is a way to implement the stresses in a FE model and then run an additional structural analysis. The residual stresses are only measured in a few points in the structure and not over the entire body. I've read that in Ansys it is possible to use the command INISTATE to implement a prestressed state but my question is what happens if I try to add these residual stresses in just a few points in the structure? Will the structure be in equilibrium? What will happen in the rest of the structure where I do not insert residual stresses?

Does anyone have experience with a similar problem?

Thank you in advance!

]]>I have a model using different types of steel and I want to know what the unity check is of these different types of materials, meaning that I want to create a user defined result using the elemental mean von Mises stress divided by the tensile yield strength of the material?

so expression will be something like: = SEQV / (**Tensile Yield Strength**)

with setting the properties:

display option: elemental mean

Is there an expression possible for retrieving the **Tensile Yield Strength **of the material?

First I create a spring element type then I assign a real constant, after this I model two nodes and create an element, when applying a displacement there is no problem but when applying a load there is warning (see attached image).

Any idea on how to solve it?

Thank you in advance

Note: For older versions, there seems to be no issues.

]]>I have received these properties from the manufacturer. I want to know how to input these properties in ansys workbench to run analysis

]]>Following the recommendations of running a 2d analysis with a single element (PLANE182), with the bottom nodes constrained in all directions and the nodes at the top with the cyclic loading in the Y direction, I still get strange results, for instance even though the strain in y-direction has the highest value the stress in the x-direction is the highest with a value of 0.2339E6 MPa. I also observed that the damage Df is extremely high (71) while it should be between zero and one.

I am attaching the Fortran code and the input file for anyone to check if there is an error.

Thanks in advance.

]]>I'm trying to simulate a soft pnuematic actuator (artificial muscle) with two components, Skeleton cover by Skin, and operate with vacuum pressure inside to create contraction and generate force.

I tried to simulate it in Ansys Static Structural by apply negative pressure at skin, fix one end of skin, define frictionless contact of skin to skeleton (also skin to skin) and turn on large deflection. Material is LDPE for skin and Brass C26000 for skeleton.

Since skin is a thin membrane (0.2 mm), I use shell element at the skin. And after some digging, I found that I have to use membrane element by adding some command to the skin to calculate only membrane stiffness (No bending).

I'm not sure how to set the simulation setting to obtain the correct result without any warning and error.

Please, give me some advice.

]]>My name is Prasanna. I'm currently trying to implement a non-linear analysis of a polycarbonate with glass fiber infusion.

All i have is a MAT24 material card where the plastic strain to stress values for various strain rates are given.

In the engineering data, I used the LS DYNA material model for the piecewise linear plasticity (MAT24) and input the data. But when I open Mechanical and look at the material properties, the Non-linear properties are set to false.

What exactly am I missing in the material properties to turn on non-linear properties for the material.

I unfortunately cannot upload any information regarding the material due to the confidentiality.

Any help or even some directions would be greatly appreciated. I'm quite new to the world of plastics and hence finding it a bit difficult to understand the material model implementations.

Thanks and regards,

Prasanna

]]>Any help would be greatly appreciated,

thank you.

]]>I made a traction test of a composite specimen. I plotted the stress-strain curve and i want to identify the point where the failure occurs. I inserted inverse reserve factor but i have some questions about how it works:

The IRF is the inverse of the safety factor, so it's the ratio between max stress and stress limit, but, if the IRF is related to the entire composite which are the stress limits? How can i use IRF to determine the failure stress of the composite?

Another related question: i made two simulations, one with the damage initiation criteria and evolution law, and one without. If the damage occurs only when limits defined by a criteria are rached (I used Hashin), why the slope of the two curves (the one from damage and the one without damage) are different even before reaching the limit?

Maybe these are dumb questions but i hope you'll help me.

Thanks for your help!

]]>Thank you

]]>**σ = D.ln(U) [1]**

**(D here is the linear constitutive matrix, and U is the right stretch tensor) I verified that ANSYS uses this model by simulating in both ANSYS and my own Matlab FEA code and matching the results for multiple cases. **

I have tried to look up the theoretical and experimental basis for using this constitutive law in literature. I did not find the exact same relation cited in any paper. I however discovered the Hencky elastic model which uses a linear relationship between Kirchoff stresses and left logarithmic strain.

** J.σ = D.ln(V) [2][3][4]**

**(V here is the left stretch tensor, J is the determinant of the deformation gradient tensor F)**

This model has been extensively researched and has both a theoretical and experimental basis for using it. Both these models are NOT equivalent, which can be proven easily.

My question is why does ANSYS use this particular model, and what is the theoretical/experimental background to it?

[1] ANSYS theory manual.

[2] *Hencky's elasticity model and linear stress-strain relations in isotropic finite hyperelasticity* , Xiao et al

[3] *On H. Hencky’s Approximate Strain-Energy Function for Moderate Deformations, *L. Anand

[4] *Henky's elasticity model with the logarithmic strain measure: a study on Poynting effect and stress response in torsion of tubes and rods*, Bruhns et. al.

does anyone know how can I import some key points to ANSYS APDL?

I have some key points in the text file from modeling but there are a lot and I can't manually add them. is there any way to add them to ANSYS APDL?

please see the attached photo.

I have a pendulum made of a magnet (one end is fixed, and the other has a magnet). I want to model the transient effects of the pendulum's magnetic force on a metallic beam located beneath the pendulum. I thought I could use ANSYS Mechanical for this purpose, but the problem is that I cannot find a way to define this magnetic force in it. I have an analytical relationship that gives the applied force based on the distance from the pendulum. However, I couldn't find a way to link the magnitude of a force in ANSYS Mechanical to the distance of two points (one located on the pendulum and the other one on the beam). I would be very thankful if you could give me an idea to model this problem. Thank you.

]]>I've been trying to use the */Contour* Funtion to modify the contour plots I'm using. The idea is to plot only regions of my model where the stress is over a certain value . Is it possible to obtain such with the following command?

**/CONTOUR**, * WN*,

`NCONT`

`VMIN`

`VINC`

`VMAX`

For me it is important to define the VMIN , while the VINC and VMAX would be automatically calculated.

Thank you!

]]>I have a question about composites. I want to perform some simulations, which are random vibraiton for composite materials. However, 2-3 years ago, I searched and I understand that, there is no theory to evaluate analysis results. Such as, when we use steel, we can check 3sigma stresses with endurance limit, however I dont know how can I find endurance limit for composites? Can I find?

Thx.

]]>I am doing an assignment for uni, I've got a script that I have modified to my data in the file.

When trying to list elemental results for stresses I get this warning:

PRINT S PRIN ELEMENT SOLUTION PER ELEMENT

*** WARNING *** CP = 2.922 TIME= 22:55:34

No data is available for the selected model or data location

specifications.

I have tried setting SMP, with no luck, is there any command to set SMP inside APDL?

]]>Im doing a structural analysis, which has a rectangular bar insiede a 'wall', and i applied **1. A fixed support at the top face & 2. a lateral displacement on outer wall on positive X direction, as below figure shown. **

Contact: for geometry, the left surface and solid inner wall were attatched with 0 gap; for contact setting, I set it to frictional with 0.1 coefficient, as I supposed that there will be a sliding friction.

1.My problem is, the result always gives a penetration that the entire solid wall penetrates the bar with same distance as doundary condition. After I set stabilization damping factor as 1. The penetration reduced to a tiny value but i still dont want it.

2.Another problem is however i got a '**possible**' result, but I dont have any stress on the contact area of the bar, as my assumption was, there should be a stress area occoured at where the two items make contacts, like a line perhaps? But theres not.

The stress can be seen at the boundary of the solid wall but that is not what Im observing.

So, any ideas guys?

Thanks in advance.

Regards,

]]>*** ERROR *** CP = 32.859 TIME= 23:12:00

An unexpected error ( SIG$ILL ) 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.

I have already looked through Google search and this forum but none of the threads gave a solution that worked. Note that the .ans file I ran works on another pc just fine. Information about my pc:

Windows 10 64 Bit

CPU AMD FX-8320

RAM 16 GB DDR3

GPU Nvidia GeForce 760

Windows and all drivers are up-to-date. Many of the solutions in other threads mentioned that "distributed solution" should be turned off in the process solver options. However, I am using APDL and I can't seem this option. I did see some options in the APDL launcher under "High Performance Computing Setup", where I tried all sorts of combinations but none of them worked.

Any help would be greatly appreciated!

]]>I'm trying to move part of compliant mechanism, while the ground is fixed. First picture is the part that has to move in a circle around a point shown in second picture. Thin parts(cross-axis flexure joint) are replaced conventional revolute joints and are easily bendable. Two holes at the bottom of the mechanism have fixed boundary condition.

I'm using static structural analysis. First I have set the reference coordinate system that is at the center of geometry of the second picture. Material is PLA. Then fixing the bottom two holes. The things I have tried:

- Using simple displacement, it moves the geometry in a circle not around the reference coordinate origin but rather around selected geometry that is supposed to move. It also locks the rotation of selected geometry, and therefore bends the link. The movement was specified with tabular data for X and Y to direct the geometry in a circle with radius of 20 mm around a reference geometry origin.
- Using remote displacement, does exactly the same thing as displacement without locking rotation of the selected geometry. Same tabular data was used.
- Tried implementing planar joint between two shown geometries, that can move in X, Y and rotate around Z. Then there is no movement at all.
- Tried to artificially bring the rotation center down with tabular data by having constant displacement of -20 mm in Y direction and the rotate. Still does not rotate around the geometry in figure 2.
- Tried using difference reference coordinate system, it seems that neither the of the displacements care about that parameter, the origin can be 10 m away and it would still rotate around selected geometry.
- Tried using large deflection solver on, the cross-axis flexure "explode" and there is no solution on neither of the methods.
- Met with two PhD students that are good with APDL, but none of them were able to help with the problem.

Is there a way to move specified geometry or point around a specific origin or geometry?

]]>This is a column.

3d analysis

line element is created in SpaceClaim.

Boundary conditions:

Hinge support on both sides. ( x,y,z translation fixed, x,y,z rotation free )

Dead load is activated with standard earth gravity.

Problem:

I am receiving a Solver pivot warning.

How can I fix this error?

]]>Thanks for your feedback!

I'm trying to calculate the mode I of energy release rate in an adhesively bonded DCB. The value of G1 is negative and it is strange. I would be grateful if you could give me your suggestions to solve the problem. The image of the model is as follow:

Boundary conditions: The two middle layers are adhesive and the upper and lower layers are Al.

The calculated value of G1:

The per-Meshed crack

Regards,

]]>The result of modal analysis shows displacement of pushpad but the rib escape from a gap between rollers.

What I expected was that the rib parts bend as the pushpad moves along y axis with the rollers as fulcrum(but can rotate)

How can I modify the conditions of the problem to get reasonable answer?

Thanks in advance.

These are photos of the model.

- Bottom surface of the lower part(spinepad_quarter) is fixed.
- Thickness of the rib is 0.3 mm and assigned material is Stainless steel 304 CSP 3/4H
- Cylindrical support condition(only tangential is allowed) is assigned to rollers.
- Symmetry normals are X-axis and Y-axis.

- Overall scheme

2-1. Contact condition of rib surface and a roller(outside)

2-2. Contact condition of rib surface and the other roller(inside)

3 Result of modal analysis

I am running a model with one element, and giving it anisotropic, nonlinear behaviour.

In order to check my results, I need the stress values in the centerpoint of this element.

How do I do this?

Kind regards,

]]>I want to develop a UPF for the HGO material model. I wanted to try the usermat subroutine for this. However, my material is supposed to be (nearly) incompressible, and I have read that usermat.F does not support these types of materials. Instead, I should use userHyper, but I guess this is not allowed for anisotropic behaviour. Since I am using version 19.2, I do not have access to the UserHyperAniso.F subroutine.

Any thoughts on which subroutine I should work with? Could I really not continue with the usermat.F subroutine for (nearly) incompressible materials?

]]>these collums go into my design while thats not the problem the problem is that they need to get a 45 degree angle between my platform and the collumns how can i trim these so i can get an angle onthe the end. this needs to happen in the program nTopology

]]>As shown in the image bellow, everything went ok.

But wen I tryied to redraw the part and perform the same exercise in a 3D analysis, I found the following errors:

Does anyone have any idea what to do to solve this? I've already tryied to increase the number of substeps, weak springs, etc... but none of it helped.

Also, I'd like to ask where can I find information on how do I use the Command (APDL) to change the element type of the interface mesh to Inter205 insted of Inter204.

Thank you for the help!

]]>If you could please advise I would really appreciate it, thanks!

]]>The support is subjected to the following loading conditions shown below.

- Interface 1: 0.75 inch diameter pin. The pin is to be considered infinitely stiff.
- Interfaces 2 – 5: 0.375-24 AS3239-26 machine bolt. Nut face 0.405 in. max ID and 0.558 in. min OD. The bolts are to be considered infinitely stiff.
- Load Conditions:
- 1. Max static linear load of 8,000 lbs vertical up.
- 2. Max static linear load of 8,500 lbs horizontal out.
- 3. Max static linear load of 9,500 lbs 42 degrees from vertical.
- 4. Max static torsional load of 5,000 lb-in horizontal at intersection of centerline of pin and midpoint between clevis arms.

Question 1: Regarding mesh convergence, should I make a study at the four loading conditions previously mentioned, or is it only necessary to make the study taking only one loading condition?

Question 2: When performing the support edge condition applying remote displacement, I must consider the constraints generated by the support bolts in both displacement and rotation. Which displacement and rotation components should be free or fixed? (as shown in the last screenshot).

Why the way my case is of structural assembly (large)

]]>Why we can't apply remote point scoped to remote displacement and remote displacement scoped to moment for a cut section of say like ( ship) ?

Applying only moment doesnot give me freedom to free other dof( like rotation)

What's the substitute, if I want apply moment along x axis but keeping other translation fix and one rotation out of three free.

Also I found even if I use remote displacement there is limit to apply moment value (10^6), I want apply more than that.. What's substitute in ansys?

]]>I am getting such kind of errors in solver output.

what is predictor?external and internal equations means?

How to fix?

]]>I am modeling a composite structure, structure is defined with surfaces (2D). I have done this procedure before. First I model and apply loads and then use ACP to model the composite laminate. Now my problem is that in ACP Pre when I want to define the oriented element set, I get this error:

Elements have several common nodes but no common edge. Check mesh!

While before going in ACP Pre I solved the model in Mechanical. Can anyone help me in finding the elements and nodes which are causing the problem. The structure consists of 800 parts and I removed some parts and then added the other parts, it works properly when I model each section of the structure but just as I mesh whole of the structure I get this error.

Thanks in advance

Thank you

]]>I want apply on one end bending moment and on centre point load.

What shld be boundary condition on both ends?

And if it's case of 3d structure in place of beam what shld be boundary condition than?

]]>I know 3 ways

Correct contacts

Correct your BCondition

And wrong defeatured mesh

If I have share topology already open, why I will still have solver pilot error due to " wrong contact".

]]>I can't defeature, because than mesh fail.

So only option with defeature setting to yes.

I am not expert in changing tolerance value of defeature.

Guide me guys.. Any ideas?

I put also in variable manager, contactallow empty 1 but one time I got simulation but other time it again start failing for same meshed structure.

I am pisssed, it wasted my 5 days

]]>