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Found 639 results

2. ## optistruct Optistruct Choosing Direct and Iterative Process Solving ?

Hello, Is there a way I can have control over how I want the model to be solved? Between Iterative and Direct Method? Can I have control on sparsity matrix? Thank you for your time!
3. ## optistruct Solving Linear and Nonlinear Models? Direct / Iterative methods?

I did some research and saw on Altair Documentation that both Linear and Nonlinear models are solved by Direct Methods, Boeing Solver for linear static and MUMPS solver for nonlinear static, My understanding, and what I see on my .out file, is that nonlinear models are solved iteratively instead of direct as documentation suggests; So, my next questions are: 1) NonLinear quasiStatic is solved in an iterative or direct method? 2) What does the documentation mean that the default solver for non linear static uses a direct solver? Thank you!
4. ## Error 158: Error encountered when accessing the scratch file

I am receiving the following error while trying to run a job on a Linux cluster: (Scratch disk space usage for starting iteration = 2704 MB) *** ERROR # 158 *** Error encountered when accessing the scratch file. error from subroutine xdslrs Solver error no. = -702 This may be caused by insufficient disk space or some other system resource related limitations. Try one or more of the following workarounds if you think otherwise and if this issue happens on Windows. - Resubmit a job. - Avoid writing scratch files in the drive where the Operating System is installed (start the job on other drive or use TMPDIR/-tmpdir options). - Disable real time protection at minimum for files with extension rs~ . - Use of environment variable OS_SCRATCH_EXT=txt may help. This error was detected in subroutine adjslvtm. *** ERROR # 5019 *** Specified temprature vectors (1 - 1) out of allowed range (1 - 0). This error occurs in module "snsdrv". ************************************************************************ RESOURCE USAGE INFORMATION -------------------------- MAXIMUM MEMORY USED 4985 MB IN ADDITION 177 MB MEMORY WAS ALLOCATED FOR TEMPORARY USE INCLUDING MEMORY FOR MUMPS 2929 MB MAXIMUM DISK SPACE USED 5939 MB INCLUDING DISK SPACE FOR MUMPS 3934 MB ************************************************************************ I've tried some the troubleshooting suggestions in the error log without any luck: I've specified the scratch drive to a large file system (petabytes of storage) I've set OS_SCRATCH_EXT=txt Since this is a high performance computing environment, I don't have the ability to access "real time protection" options; however, I'm not aware of any virus protection running on the cluster and, furthermore, the OS_SCRATCH_EXT=txt should fix virus scan issues as I expect the system would let text files pass. I should note that I am trying to run this problem as a parallel job with the following command: \$ALTAIR_HOME/scripts/invoke/init_solver.sh -mpi pl -ddm -np 2 -nt 8 -scr \$SCRATCH -outfile \$WORK <filename>.fem Below are some other relevant notes: If I try to run this job in serial (i.e., without the -mpi pl -ddm -np 2), I don't experience the above error; so, this appears to be something that arises when trying to run mpi jobs. I've tried running this job with -mpi i and my system doesn't seems to be setup for intel based mpi (unable to find required .so files). Cluster node information: Dual Socket Xeon E5-2690 v3 (Haswell) : 12 cores per socket (24 cores/node), 2.6 GHz 64 GB DDR4-2133 (8 x 8GB dual rank x8 DIMMS) Hyperthreading Enabled - 48 threads (logical CPUs) per node The \$SCRATCH drive I'm pointing to is a network drive. I tried running -scr slow=1,\$SCRATCH, but still get the same error. When I make the above ddm call, I have requested 2x nodes and a total of 48 mpi processes (although I'm not using them all) Thoughts?
5. ## Variable temperature in a BEAM

Good afternoon, I have a BEAM (CBEAM) component and I would like to see how it deforms due to a VARIABLE TEMPERATURE applied to the whole BEAM. Is that possible? Obviously I would only like to see how it deforms on the direction of it's axis (as a BEAM is a 1-D element). The TEMPERATURE would go from 17 to 23 degrees in 6 hours (1 degree increment every hour) Thanks a lot in advance! Sergio
6. ## Thermal radiation

Hi I am trying to perform a (transient) thermal analysis where a composite plate is subjected to radiation. The plate consists of 2 plies, the one on top is made of glass, the one on the bottom is made of aluminium. The radiation needs to go trough the glass and then reaches the aluminium plate. The aluminium absorbs almost all of the radiation, the glass mainly lets the radiation trough and reflects it. How would I model this? Is it possible to do a thermal simulation like this with hyperworks software, like optistruct or radioss? I already looked at the tutorials but they don't match my case. I also tried acusolve but here it is not possible either because radiation through glass cannot be simulated properly.
7. ## Sets of TLOAD

Good morning, Could you guys tell me what is the card to put together two TLOAD? For example to put different SPC we can use SPCADD. Thanks a lot in advance!
8. ## optistruct Center Of Gravity of a SET

Hello, I would like to know the center of gravity of a set of elements from my model. Currently I only know how to obtain the center of gravity but for the whole model (post--> Summary) But, how can I make this with a SET? thanks in advance.
9. ## lgdisp Nonlinear large displacement direct transient analysis problem

Hello, I work on a suspension construction. I have done done a static analysis due to vehicle mass (I managed to do both linear and lgdisp nonlinear). However, I also need to perform a dynamic analyis due to riding over an obstacle and I have encountered few problems with the simulations: 1) As an excitation I use a displacement of a triangular shape (picture below). It works fine for the direct transient (linear), however, when performing nonlinear direct transient (with and without LGDISP on) the excitation is not as I intend it to be (second picture). The plots show the displacement in the Y direction in nodes where the displacement is applied in the model. The actual input load data is a triangle as in the first picture. Therefore, I do not understand why when performing nonlinear transient the displacement starts to increase before it is larger than 0 in the input data. There should not be any loading applied before 0.100 s and when changing to nonlinear analysis somehow there is a loading. Also the system does not go back to the zero position. 2) the second problem is that when i use nonlinear direct transient the simulations calculates without any problem but when turning on the LGDISP option I encounter convergence problems: *** ERROR # 4966 *** Minimum time increment reached, analysis aborted. I tried changing the minimum time increment but it does not help. I use TSTEPNL and NLADAPT setup. What options should I change so that the convergence problems does not happen? Thank you very much in advance for any help.
10. ## optistruct Coordinate System CORD2R vs CORD3R Difference?

Hello, What is the difference between CORD2R and CORD3R? What are their properties? If I reference joints to a specific coordinate system what would the difference be with CORD2R and CORD3R? Thank you!
11. ## Optistruct doesn't start at all

Hi all, I got Windows 10 and the Hyperworks Student Edition 2017. I can start the Hyperworks student edition and create everything up to a model which is ready for the analysis with Optistruct. The problem is, when I try to start the analysis with Optistruct nothing is happening (at the down-left corner something running but it stops on "Ready"). I also read the other topic but that solution doesn't work for me either. I already tried to uninstall and install the program several times to different directories but nothing helps. I am trying to fix this problem for a week now and I'm starting to get desperate. I really need this program to work for a university project and I hope someone can help me. Thanks in advance Spaessel
12. ## optistruct MOTNJG Behavavior doubt?

Hello, I am using an axial joint and want to to add motion to it. My questions are: 1) Which node moves relative to who? a. Node1 Moves and Node 2 Does not move b. Node 1 does not move and node move 2) If i was to assign a DOF = 1 in MOTNJG does this mean that the node moving wil move in the axial direction of my joint? Thank you!
13. ## Topography optimisation

Hi, I want to run a topography optimization of a sheet metal component, but I would like to restrict the shape change with barrier mesh inside and outside due to the adjacent components. How can I do this?. Can someone help me with this concern?. I know that barrier mesh option is available in free shape optimization but I really want to make use of only Topography optimization as it is a sheet metal component. Thanks and regards, Punith
14. ## How do I fix the time step in nonlinear transient analysis?

Hi, My loadstep, TSTEP and NLPARM are as follows In the result, the number of the time data is 432. (Its time step is not 0.0001) I learned that when NLPARM and TSTEP are used together, DT on NLPARM overrides DT on TSTEP. This result is caused by incremental load based approach in OptiStruct? Thanks
15. ## Compressive Analysis

Hı everyone, I want to do compressive analysis with optistruct. My compenent is Sheell so I used to PSHELL card. But the program want from me T parameter. I know T is Thickness and shoul be greater than one. but I dont know is it component thickness or other somethink. How do I adjust it. Thank you. .
16. ## Sensitivity analysis - Topology Optimization - Adjoint Method

Hello, The Topology Optimization in Optistruct by default uses the Direct method for the Sensitivity analysis. I am predicting the result variation using the Adjoint method. It would be of great help to me if I know the way that I can make the solver use the Adjoint method of Sensitivity anslysis. Any help is appreciated! Thanks!
17. ## h3d error

hi everyone, I have run my model but the software do not create .h3d file best regards hi moderators, r13.fem

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19. ## error 312

I got an error when I run optimization. ************************************************************************ A fatal error has occurred during computations: *** ERROR # 312 *** In static load case 1 the compliance is negative or large -5.62632e+013. Optimization/buckling analysis cannot be performed. due to possible rigid body mode. INFEASIBLE DESIGN (AT LEAST ONE CONSTRAINT VIOLATED). *** SOME ERRORS WERE REPORTED DURING THE RUN, *** PLEASE VERIFY RESULTS AS THEY MAY BE INVALID. ... ************************************************************************ But it didn't have rigids. 1.hm
20. ## Non-Linear Buckling analysis for hyperelastic material

Hi, I am trying to solve a non-linear buckling analysis using Altair Hyperworks with Optistruct as a solver. I am unable to find the load step for it. Both non-linear static and linear buckling work. linear buckling won't accept NL static as input or as a STATSUB Preload. Is this option for non-linear buckling even available in this solver? or do I have to use any other solver. please advise. If there is any example available for this kind of analysis, that would be a lot of help. I couldn't find anything in the ebook "Non linear FEA using Optistruct".
21. ## Dynamic buckling beam - imperfection

Hello, I work on a vehicle suspension optimization. For that purpose I need to perform a dynamic buckling analysis of a tube (meshed by 1D beam elements). I have already performed static analysis, static buckling and modal analysis and the next step is performing dynamic buckling with force impulse. In order to perform this analysis I need to apply an imperfection of the geometry (initial deformation). The imperfection is supposed to be the first buckling mode from static buckling and the corresponding displacements are assumed as a coefficient 0.01, 0.05 etc. Therefore my question is whether it is possible to apply such buckling mode imperfection in OptiStruct, if so where I can find this option? Thank you for any help in advance.
22. ## Incremental output of GPFORCE or SPCFORCE in NLSTAT simulation

Hi, I'm running a NLSTAT (quasi static simulation) analysis with geometric and material nonlinearities with large displacements. I need Reaction forces of all incremenets in a specific spc node to get the FORCE/TIME STEP graph. I read before that this output of GPFORCE or SPCFORCE is not supported in older versions. What about the latest one? Is there something I have missed? Also what is your suggestion on alternative, if that output is not supported? Dynamic implicit simulation? Thanks for your answer!
23. ## How to use connectors between two component

Here is my .hm file. I would to connect the design and non design component as a whole but i still do not manage to do it. Please help me guysss !!!! TRY.hm
24. ## optistruct ERROR # 605 (Laminate Stack Set ERROR)

Hello,Forums I am doing analysis of a unique CFRP pipe by Optistruct. I am receiving this following error message:﻿ *** ERROR # 605 *** Element 1 is referenced by STACK 1 (on PLY 1) and by STACK 2 (on PLY 5) simultaneously. Different stacks are created by dividing the upper and lower areas of the pipe into sets. There seems to be an error because it refers to the same element Is there any good way to do it? (Modeling is possible but analysis is error) CFRP-PIPE-Asymmetric laminated.hm
25. ## Non-linear elasto-plastic material

Hi everyone, is it possible to define as input data the behaviour curve of a non linear elasto-plastic matierial in a MAT1 card image material with the NL parameters activated? I tried to import the curve, changing the TYPSTRN value, but the solver Optistruct does not start. The curve has non linear trend both in the elastic that in the plastic phase. Bests Martina
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