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Found 621 results

  1. Hi everyone, I am simulating a tensile test of a homogeneous isotropic material, according to the coupon bar example in "Introduction of Non Linear Finite Element Analysis using Optistruct". I imported a different material and the coupon bar geometry is a bit different. I do not understand why the numerical force -displacement curve decreases after the yielding point, while, for example in the ebook, it follows the input trend. I though the possible problems could be the definition of the true stress-strain curve, or the NLQS parameters NINC and NLOUT, the chosen finite elements (tetrahedral; I used this type because I have to calibrate the material to perform analyses on more complex geometries). Can anyone find the problem? I attach the .fem file (ModelB_prova_NLQS). In additiion I attach a model that behaves as expected (Model2_surf_prova10_NLQS ModelB_prova_NLQS.fem MODEL2_surfs_prova10_NLQS.fem
  2. 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
  3. Hi everyone, I need to define a surface from a set of lines that represent level curves of a set of mountains. The creation of surfaces from lines does not work well. Is there a way to obtain good surfaces? Bests Martina
  4. 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!
  5. Hey guys, I’m a mechanical engineer student and I participate in a project where I analysis the structure of a modern tricycle. I need help with the fatigue analysis. I make the training of fatigue by Altair and tried make the analysis, but I’m not sure of the results. I think the problem it’s on the TABFAT. About the TABFAT: My analysis has 1D and 2D elements. I obtained the following values in the Linear Static Analysis: Analysis 1D Analysis 2D σ_max 24,59 MPa 267,9 Mpa σ_min -19,71 MPa 0 MPa Can I represent the load cycle of my “vehicle” like a sinusoidal curve? Can you show me how I represent it? Should I represent these values for each of the fatigue analysis like one analysis for 1D elements and other analysis for 2D elements? Can I “mix” these values for the two analyses representing σ_max = 24,59 MPa and σ_min = -19,71 MPa? I think that a correct method is consider my load cycle like a variable load, but I don’t obtain experimental data. About the MATFAT: I acquired the MATFAT data by the eFatigue website, but I don’t obtain the SE (standard error of log(N)). How I find out this? If I consider SE like “Default” (zero), how will affect my analysis? Note: I’m making a SN analysis. Thanks for helping!
  6. Hello! I want to measure the volume of a solid. I know I can find this in Tool --> Mass Calc I am interested in measuring the volume with more numerical precicion. Is there a way of increasing this? For example i would like to read more numbers beyond 2.781 as the image shows. Thank you
  7. Hi guys, I would like to know if its possible to update my hyperworks 2017.2 to 2017.2.1 in order to inlude certain features especially overhang constraints in my simulation. Thank you.
  8. How can we prove Topology Optimization method by Analytically/ Mathematical modelling. If not complex any Simple structures to show results matching with CAE techniques. ?
  9. Good afternoon, I'm trying to mesh a housing and I wanna model parts of it with SHELLS and others with SOLIDS. How do I connect both? Thanks!
  10. Hi everyone, I am simulating a tensile test with Optistruct. The analysis is NLQS and the material is isotropic. I set the analysis as proposed in the eBook "Introduction of Non linear finite element analysis using Optistruct", section 3.1.5 Tutorial: Small-Strain and Large-Strain Plasticity in a Test Coupon. I would like to understand how to set the CELAS1 element in order to use it for the building of the force-displacement output curve. I created the element, but the output curve results flat, so I think the problem is the Set. Attached is the .fem file, is usefull. Bests Martina MODEL2_surfs_JarvO1_NLQS.fem
  11. Hi everyone, I am modeling a 3D hollow element made by more components in Hypermesh to conduct NLQS analysis with Optistruct. My system is symmetric and I want to know if there is the possibility to tell the software that the unmodeled part is the mirror of the modeled part, so that it considers the constraints due to the symmetry. I know the software allows to reflects elements, but I would like to not works with too many nodes. I attach pictures: 1 is the modeled/discretized part; 2 is the entire system (modeled, unmodeled parts) Thanks Martina
  12. Hi everyone, I am simulating tensile tests with welded samples. I am using NLQS analysis in Optistruct, according to the eBook Introduction to Non Linear Finite Element Analysis using Optistruct. My problem is that the stress-displacement curve after the simulation shows stresses which value is higher than the ultimate stress imposed with the TABLES1. How is it possible? Why the stress-displacement curve does not become flat? Does it have any meaning? Bests Martina
  13. Hi guys, i have some questions and problems with the tutorial OS-T 1600. 1. First question: What is the best way to start a FSI-Simulation. The way in the Tutorial, or the Co-Simulation Tool (Picture 1) (Picture 1) 2. Second question: When i start the FSI-Simulation i get an error (Picture 2). (Picture 2) I think i use the wrong hostname. Could anyone explain, what i should insert in the green field (Picture 3) (Picture 3) Thanks Michael
  14. Hello all, I am currently working on NVH Frequency response analysis with optistruct and nastran solvers and I see an error of opproximately 10%. Same FEA model has been used in both solvers and the error is 10%. If both the models are created in their corresponding solvers, then the error comes out to be 7%. How good is Optistruct solver for NVH to match Nasran solver? Any benchmarking done on this? Please help me out. Thanks and regards, Punith
  15. Hello, i tried to solve the Optistruct OS-T 1600 Tutorial, but after starting the two solvers (optistruct, acusolve) there is a convergence error of acusolve that stops the job: Messages for the job: *** ERROR # 5202 *** Acusolve stops before FSI iteration achieves convergence. *** PROGRAM STOPPED: FATAL ERROR(s) ENCOUNTERED. Does anyone knows the problem? I checked all steps of the tutorial and start it again, but the error still appears. The next step was to change the exchange parameter of acusolve (min/max_stagger_iterations) and optistruct (min/maxEX) to 30. A Simulation of the Tutorial with only 0.02s worked. To simulate the tutorial 0.1s or the whole 1s - as it is described in the Tutorial- still doesn´t work with a value of 100 for max_stagger and MAXEX. Another error appeared: Does anyone has got experience with the tutorial OS-T 1600 and solved it successfull? Thank you very much in advance.
  16. hello everyone, i want to do an optimization in order to increase the correlation between experimantal results and numerical ones, using MAC cretria, my design variables are the stifness of the damping springs. my size optimization is well set it works but i don't know how can i connect the expermental result that i have in an .UNV file and the numerical results. to say to optistruct i want to increase the mac between the two. i know that i have to use the parameter TRAKMETH MODETRACK MFILTER. but i don't know the right steps to operate this one. if you have some ideas i will be greatful thanks.
  17. Hello, I would like to export the residual stress results from a forming simulation in Hyperform to carry out a structural analysis of the formed part in OptiStruct. Could some one please share a tutorial based on this workflow? Thank you in advance. Regards,
  18. I have worked before with Pretension analysis and pretension manager on Optistruct. I am obtaining this error at the moment *** ERROR # 3090 *** Normals on the cutting section of PRETENS #20 are not consistent. Do you kow what this means? Thank you!
  19. Hi everyone, I am performing a non-linear quasi-static analysis on a system made by elements with different materials and geometry. I attach the files. The system has an SPC for dof 1, 2, 3 at the bottom part and compression pressure on the other 3 sides. The problem is that the analysis does not converge because of error 4965. Is this a problem of the load pattern or load type, or a problem of analysis parameter setting? Before this trial I performed on the same model a non-linear quasi-static analysis of simple tension along x axis imposing a displacement on the right side of the system and an SPC for dof 1, 2, 3 on the left side and the analysis converged. After this I imposed the displacement also along y axis, but it didn't converge, so I tried with forces, and then pressures, but the analysis didn't converge. If the problem is the load setting, the definition of an envelope of the vertical loads with the horizontal loads could give good results? Bests Martina Simm2D_full_compression.hm
  20. Hi everyone, I created an external unit cell, meshed it in Hypermesh and defined everything according to the Multiscale Designer Manual - Periodic mesh on opposing faces of unit cell - 3D mesh with only CTETRA elements - One component for each micro-phase (with component ID 1 & 2) - One property (PSOLID) for each micro-phase (with property ID 1 & 2) When I try to import my .fem-file in MSD I get the erroro message depicted below. I tried to import the external unit cell from the examples folder of Multiscale Designer and that worked. So the setup of my MSD works in principal but cannot import my file. Does anyone know how to resolve this? Thanks for your support.
  21. Hello, In Ansys and Abaqus solvers I Used to apply a "Skin" (2D elements based on the outer surface of 3D elements) on castings in order to read superficial stresses in Hyperview. These elements were membrane elements and were declared different than regular shell elements. For Optistruct which type of element is the one suited as membrane element? Is there any other approach to read superficial stress on castings? Here is an image of the availabre trias type of elements, which one should I Use? Thank you for your time!
  22. Hello, I have performed a transient thermal simulation with OptiStruct. I want to get the surface average value of temperatures in a surface for all the time steps, but I don´t know how to get it. Do you have any idea of how to do it in HyperView? Thank you very much Juan Iradier
  23. Hello all, I'have a problem with a file .fem. I try to start the calculation with optistruct, but few minutes later an error appears and the calculation stop. The error is error#1260 "Missing subcase information in the input file". I have checked if the nodes where the force are applied are connected, and the nodes are ok. Can you help me?
  24. I attempt to go through Toplology Optimisation with relative displacement (in x, y, z) as constraints and loadcases. SoI need to select all the nodes displacements at certain cross sections, where there is the only path transfering force to design area. I am new to optistruct and hyperview, I just noticed it is possible to select cross section and read also output every nodes' displacement in Excel. My question is, does it work in this way? and if yes, How should I input these data (should be more than hundred nodes) into Optistruct as an easy way? A tutorial would be so appreciated! Cheers!
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