is it possible to assign radiation to both sided of the shell using Enclosure Type=Perfect? In GUI I can see only "Top" and "Bottom".

I have a question regarding the Multilinear Isotropic hardening in Ansys, more specifically the mismatch between the input material stress strain curve and generated curve in Ansys.

I have created a simple 2D model (plane stress), which is supported on the left side (fixed support). Load is added on the right side in a negative Y direction. I used second order hex mesh and applied local sizing to the edge where the stresses are the highest.

For elastic material properties I have defined Young’s Modulus (160 000 MPa) and Poisson's Ration (0.33). Yield point of the material is 410 MPa, at 0.002 plastic strain (determined with the offset method). The elastic limit is set at 345 MPa. For plasticity I have defined Multilinear Isotropic Hardening, where the first point in the table is the elastic limit at zero plastic strain. All points in the table taken from the true stress strain curve. Auto time stepping is turned ON (min 200 substeps), as well as large deflection.

With the load of 300 N, stresses in the magnified corner exceed the yield point.

I have created a Named Selection on the node in the proximity of max stress and plotted max unaveraged Von-Mises stress versus max unaveraged total strain to create a stress-strain curve. As you can see from the right graph, the stress strain curve from Ansys is not completely aligned with the material curve. In the elastic part (up to 345 MPa) the curves are completely aligned, but there is a deviation as soon as the plastic strain occurs.

Eventually the curves realign, and if the stresses are well beyond yield this mismatch is not a problem. But I am interested in the region just below the yield, therefore this deviation is not acceptable, as the difference in stress, for example at 0.003 total strain, is around 20 MPa.

Can anybody help me how to resolve this issue?

]]>figure-1

figure-2

I will be glad if you give an idea!

Regards

]]>I was trying to model a bonded connection between to shell edges but I keep having this Error pop up "The normal of target element 46002 is not consistent with the normal of target element 46029 in real set 99. Please use the ENORM command to correct it." every time I tried Running it. Can Anyone help me solve this issue? I am trying to limit number of elements that's why I have two different mesh size. Shared topology would increase my number of elements or reduce/increase the standard mesh metrics. The bonded contact is at the boundary of the differing mesh sizes. When I use MPC in the formulation the Model solves but I get a weird stress at the boundary it doesn't have continuity.

Thanks.

I am trying to do prestressed harmonic analysis.

for that, first I have used static analysis and solution of static analysis used in harmonic analysis

One silicon cylinder membrane clamped on edge and using trans126 I haver applied 400v (ramped). Static analysis works fine but in harmonic analysis I didn't get any plot.

Could anyone please help me?

I have attached workbench file.

Thanks in advance

Regards,

Dhruv

]]>I did some research on the residual of the curve fitting for the hyperelastic material models in Workbench. I guess that the residual show the residual sum of the squares. I was wondering if it is possible to obtain coefficient of correlation or any other goodness of fit indicators from Workbench? Or is it possible to extract the fitted data?

Utku

]]>I want to make a topology optimization of the following slider:

At E,G,D and F there is a guiding wich is made of plastics. The outerside of the guiding is fixed and there is a frictionless contact to the slider. On B there is a trapezoidal pressure load. On the C there is a cylider, so the displacement in x-direction is 0.

There is a thermal load on the body which you can see in following picture:

When I want to make a topology optimization of the slider I get following message:

" *** ERROR ***

Nonlinear contact in combination with thermal load is not supported."

The problem is that I need this nonlinear contact behaviour so that the slider can take off from the guidance.

Has anyone an idea how I can modell the thermal load or the nonlinear contact to get an acceptable result?

Looking forward for you answers.

bokaJ

]]>I have a problem with my structural analysis.

I want to simulate 2 metal plates which are bolted together, as you can see in the following picture.

The one end is fixed. On the other end there is a force into the direction of the plate strip (5000N). There is also a force in the direction of the bolt (5000N) on the upper und on the bottom side of the plate.

At first I made a hand calculation. The section of the plate is 40mmx5mm.

So I get a normal stress on the upper side of the left plate of about -125N/mm^2 and a normal stress on the bottom side of about 175 N/mm^2.

The right plate shoud have stress about 25 N/mm^2.

I have modelled this at first with 3D elements and got also these results.

Now I wanted to model it with shells and a beam instead of the bolt. But now I get results, which can not be true.

You can see my geometry at the picture bellow:

I connected the circular ring shell, wich presents the bolthead with the plate with a bonded contact. Also the 2 rectangular plates which presents one plate are bonded together. The areas of the 2 plates which are bolted together are connected with a frictional contact. The endpoint of the beam is connected with the "bolthead" with a fixed joint.

At the first step I obtained the bolt pretension and on the second step I obtained the forces on the plate.

So I get normal stresses as you can see bellow:

The results on the right plates are correct. But I think my results for the left plate are incorrect. But I have no idea what I did wrong.

Maybe I need more integration points for the shell? But unfortunately I did not find, where I could change this in ANSYS?

I am really looking forward for answers and ideas.

Thank you very much

bokaJ

]]>Can any one help me why there is nodal distortion in my FE Model? I was doing an analysis to pre-stress my model thermally but the model doesn't looks good. Any help will be appreciated. I have attached 2 pictures one for boundary conditions and other of the distortion. It's a shell model.

Dear Friends

model is consist of 2 components: Soil/steel hollow Micropile / frictional contact (coefficient is 0.5) between soil and micropile (surface to surface), (contact pairs is closed)

BC; Bottom soil is fixed in ALLDOF/ areas on the sides of soil block fixed in UX,UY/ top area of the micropile: uplift pressure (9MPa),

LS1: GRAVITY/ LS2: Uplift pressure and Gravity

the model did not solved as the errors shown in the attached photo,

any help in solving this error appreciate a lot

]]>Due to the cuved crack front, I don't konw how to defeine the crack propagation direction. Anyone konws how to define a curved crack in ansys workbench at the interface of two materials?

So I am trying to run a simulation on this shaft with discs and vanes and the vanes and the discs are to be modelled as shell elements and the two faces are fixed as shown in the picture.

So I used the midsurface command to make them shell elements and i put the pressures accordingly and got this error. At the first run I didn't have any connections so i added frictionless contacts and ran and still didn't work. So I also put a contact tool to make sure there is not too much gap or penetration and ran again and different error.

Now I tried modelling just the vanes as shell elements and discs as solids. And tried all the steps above same result.

At the end I tried the model with all solids and it worked but that is not the simulation that is required.

Can anyone assist please

]]>Once I go back in Workbench and change (for example) the thickness of the top plate and let it run to find out what the max stresses and stiffness's are, my mechanical model completely freaks out. If I open it the given prescribed displacement is all of a sudden exploded, see second picture.

Could someone please explain what is going wrong, why do my boundary condition get overwritten?

]]>I am working in Workbench 2020. I have a model that has multiple displacements that need to happen on various nodes throughout the model. Is it possible to import a table with the node numbers and the x,y,z components of the displacements? There are a lot of the displacements and would save a lot of time to import a table with the values.

Thanks,

Troy

]]>I have created a transient thermal system and connected a static structural to it. I have conducted the thermal analysis. By default Ansys imports temperature of each node at every substep, but the only results that matter in my case are the maximum temperatures reached over time.

Can anyone tell me whether it is possible to import only these results into static structural? I would really appreciate a step by step explanation.

Best regards,

Marcin

]]>I am doing my pre-doctoral project working simulating a kayak.

The problem I got is that, when I try to mesh, I got this:

The model looks good, but the problem is when I mesh. Here is my model:

What could I do?

Thank you very much !!!

]]>(sorry for my eng) I am performing a model of pure shear in plates with different thickness for capture both types of buckling. The different plates are squares of 1[m] of length. This procedure is make in three stages

* Static structural analysis (1): Defining border conditions and lateral loads of magnitude 1 using an elastic steel (structural steel)

* EigenValue Buckling: for obtain the magnitud of elastic buckling loads

* Static structural analysis (2): Same model with Bilinear isotropic hardening for the steel Fy 250 [MPa], large deflections on, initial imperfection associated with the first buckling mode and the loads with the magnitud obtain previously are applied incrementally in 100 steps.

I do this procedure for ten different thickness from 2[mm] to 9[mm] then I draw the force vs displacement. My problem is that for small thicknesses (elastic buckling) the plate does not fail at the elastic limit and exceeds this value while for greater thicknesses (elastic plastic buckling) it does have an asymptotic behavior towards the elastic plastic buckling load having good results.

The element used in this analysis is Shell281.

note: (in the analysis with thinner plates I also used bigger values of Fy because workbench it wont let me use a perfect elastic material for the second static structural analysis)

]]>here you can find attached file ansys19.0. Also i have different beam profiles to model in single chassis is it possible to do so with the beam tool

]]>In engineering data, when I select anisotropic elasticity, why I don't need to specify the poisson ratios?

]]>The benchmark is very simple. It consists in rectangular plate, loaded symetrically in in-plane axial ("X") direction. The boundary conditions eliminate any possible movement but that along X asis. Therefore, it is a quasi-1D situation. On the other hand, we did not want to use beam elements, as the real problem at stake requires shells.

The main part of the benchmark macro is as follows:

XA=3.0

YA=1.0

THICK=0.005

/prep7

RECT,0,XA,0,YA

ET,1,SHELL181

MP,EX,1,2e11

MP,NUXY,1,0.3

MP,DENS,1,7800

SECTYPE,1,SHELL

SECDATA,THICK

ESIZE,YA/2

AMESH,all

NSEL,S,LOC,X,0

D,all,all,0

ALLS

D,all,UZ,0

D,all,ROTX,0

D,all,ROTY,0

D,all,UY,0

....

/solu

ANTYP,HARMIC

....

DMPRAT,0.05

KBC,1

freqstart=400

freqend=500

freqstep=5

*DO,given_frequency,freqstart,freqend,freqstep

HARF,given_frequency

N1=NODE(XA,YA/2,0)

F,N1,FX,-F1AMP

ALLS

SOLVE

..... postprocess of energies ....:

SET, (imaginary or real)

ETABLE, (kind of energy)

SSUM

*GET .... SSUM, ITEM,....

*ENDDO

We have determined the natural frequency of the plate associated with its "spring-like" behaviour (~450 Hz), and studied its response around that resonance. At each frequency, the various energies (TENE, SENE, KENE, AENE) are stored (ETABLE,... and summed in all elements. Both the real and imaginary parts are taken separately into account.

The plot of energies is as follows:

Now, we are struggling to understand, how the energy dissipated per cycle (EDPC) can be deduced from these energies.

The ANSYS conference paper (Modeling of Material Damping Properties in ANSYS, C. Cai, H. Zheng, M. S. Khan and K. C. Hung) seems to define the dissipated energy in the following way (page 5):

Let us call this approach "Energy-based" approach.

Further on, Cai et co-authors declare:

So it seems rational to sum up maximum strain energy (SENE or TENE) and multiply it by 2 * Pi * 2 * DMPRAT. So we do, yet problems remain:

1) Is this simple formula really sufficient, when at least three energy types are present (SENE=TENE, KENE and AENE)?

2) Which component (real or imaginary or some combination of both) should be taken into account, for proper representation of Um ?

Doubts were further backed up by our assessment of the dissipated energy in a different way - let us call it "driving-point-based" one. Namely, we calculated the real (active) part of work exerted by the force in the application point, storing its displacement amplitude and phase. We claim that the following formula is correct:

EDPC(drivinpointapproach) = |u| |F| cos (Δθ)

where Δθ is the difference of phases between the force and the resulting displacement at the application node.

In this case, it is unnecessary to think of a vector product (as F and u are made to be aligned).

As one may notice on the plot, EDPCdrivinpointapproach is different from EDPCenergybasedapproach. They are close to each other only at the resonance peak, but differ largely at frequencies far from the resonance.

**Consequently, we are looking for a precise formula for determining the EDPC from stored energies.**

Eigenvalue multiplier is 20,306 for 0,001 mpa . So my critical buckling have to be lower 0,0203. Finally ı wanted to see my model behavior for overall buckling and collapse buckling.

Can you help?

Model - R(radius)=500 mm h=1250 mm t(thickness)=1 mm

Top and Bottom simply supported (displacement x=y=z=0)

1-ansys model

2-eigenvalue multiplier

3-newton raphson -stabilization energy constant 0,001 (initial 200 min 100 max 2000 substeps) result

4-arclength commond

5-my arclength result(finished 0,63 sn and not converged)

6-true arc length grafic (wanted)

i have a question. I was doing a bending test and was hoping to apply SMART crack onto the simulation in order to see if the applied strain will lead to crack propagation within the material. I was following a tutorial for the characterization of the pre meshed crack which has worked for me in the past.

However, a questionmark is still behind the SMART crack tab. Does anybody have an idea as to what could be the problem? I have included a few screenshots.

I would be grateful for any advice or comment!!

Note that in previous runs I used either all solid bodies, or all shell bodies. Here I have both solids and a shell body.

Please correct me if I am wrong, doesnt applying symmetry constrain the object in the corresponding directions? If so, why would this node be unconstrained in those directions (X and Y)? Furthermore, if I were to constrain the Z displacement of the sample, wouldn't it be unable to deform under the load?

May I know how should I constrain the model to solve these warnings? Or could it be a result of other ill-defined parts of the model? Hope someone can shed light on this, thanks in advance!

]]>The contact surfaces on the teeth have been prescribed as frictional with a 0.1 value.

I'm using Revolute Joints to ground both gears, and in one of them I'm applying a 116 Nm torque and on the other one a rotation with zero value.

The standard element size is 3.8 mm, and I have parametrized the face sizing of the engaging teeth as input and the maximum stress on each gear as output.

And the maximum stresses location, with the results of a 2 mm face sizing.

This is the result so far, x axis is the element size (mm) and y axis is the stress (MPa). Gear 1 is the one with zero rotation, and gear 2 is the one with applied torque.

Any tips on getting the stress to converge?

]]>Here is my doubt. I did an example just to learn how combin14 beams work. Now I'm trying to define the torsional stiffness as a parameter in order to change it in the design points table in workbench.

Thank you all for your answers, regards,

Óscar

]]>Hallo.

I am quite new in ANSYS and have a problem with my model.

I have a part which is made of lot of shells. This part should slide on the rigid body, see figure 1.

The part should be able to move in the positive z-direction, but not step throug the rigid body (negativ z-direction).

In Figure2 you see the connection between the shells and the rigid body.

You see the details of the rigid body in figure3.

When I start my calculation i get the error "Not enough constraints..".

I want to get an fixed support on the rigid body. Can anyone tell my how to do this?

I also tried to use an "Compression Only Support" instead of the rigid body, but I can not choose my shells there fore.

Thank you

bokaJ

]]>Anyone would be highly appreciated.

]]>how can I relate the Foundation Stiffness offered by a circular section beam with its elastic modulus?

The only thing that I came up with is the following:

I set the elastic support on an area equal to the cross section area of the beam, and then I set the Foundation Stiffness dividing the elastic modulus for the length of the beam.

The resulting units are correct, and I believe also the physics are correct, but I really would like a confirmation of that.

Thank you very much,

Federico

]]>This is the plot of a static structural nonlinear simulation.

All the convergence criteria are PC. Only Force and Displacement criteria are available for this simulation, I can see it from the Solver Output. I know that convergence occurs when all the criteria overcome the convergence criterion for a certain number of iterations (don't know exactly how since it varies). Thus, I don't understand why the simulation doesn't convergence in a substep although both the criteria (in this case only Force and Displacement) are below the magenta line for more than three iterations. Sometimes the force and displacement keep being under the magenta line for 50 iterations or more then bisection occurs or divergence happens.

Thanks

]]>I am attempting to create a user defined result to calculate the safety factor of my beam-modeled chassis. I have done the following:

- Successfully solved my model
- Evaluated the Maximum Combined Stress for my model
- Found the code for Maximum Combined Stress (BEANMAX_COMBINED) in the solution worksheet
- I found the yield strength of material I am using, which is 250 MPa.
- I created a user defined result that with the following parameters:

However I get positive and negative infinities:

And a warning that this result could not be evaluated over all bodies.

I can obviously hand calculate the FOS, but I want the result for each member in particular.

Where is the error in my procedure?

Thank you!

]]>Today I have a question about theory.

While reading the input files in ANSYS Mechanical I see that ASEC beams have some properties defined. Those properties can be consulted in the following link:

However I want to know how ANSYS calculates those parameters (moments of inertia, torsional and warping constant, etc.).

Could you please send me some theory books where this is explained?

Thanks a lot.

Regards,

Óscar

]]>