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## Popular Content

Showing most liked content since 05/29/20 in all areas

1. 3 likes

## 99 lines of topoly optimization

Hi everyone, i'd like to share a script slightly modified, based on the very famous 99lines topology optimization script from Ole Sigmund group (http://www.topopt.mek.dtu.dk/). It brings a topology optimization problem, for miminize compliance, while keeping a limited volume fraction of material. It is a bi-supported beam example. This runs fine in Compose 2019..3+ I believe. Just load the .oml file, and run the script. Then for execution type a few parameters while calling the 'top' function. top(20,10,0.5,3.0,1.5) top(numb elems in x, numb elems y, volume fraction, penalization , minimum radius filter) 99lines_modified.oml
2. 3 likes

## Digitize plots in images

Hello all, I wanted to share with you a tool to digitize plots in images using OML and Python. The aim is to convert plots that are introduced in text books like Analysis and Design of Flight Vehicle Structures (Bruhn, 1973): Such plots are commonly used in industries like Aerospace to calculate constants and other parameters that assess Margins of Safety of components and systems. Finally, we can do a polynomial curve fitting to use these curves and compute these constants without the need to look at the plots everytime they must be applied. The steps of the attached scripts are: 1) Give the axes bounds, degree of polynomial curve fitting and image whose plot will be digitized 2) Hit Start in the OML script (it will automatically call the Python script) 3) Give a first click with the mouse button to start selecting the corners of the plot 4) Select the corners 5) Give another click to select the points 6) Select as many points as you want 7) Double click with any key to finish the selection 8) Plot is generated and polynomial coefficients are computed and printed Regards, Roberta PlotDigitizer.oml ginput_plot.py
3. 2 likes

4. 2 likes

## readmultvector, readcae: why are they 2?

There are multiple commands to extract CAE/Test data file in Compose OML. of which, readmultvectors, readcae commands extracts results of specific input arguments given by the user. I had multiple requests from users asking, as these 2 functions serve the same purpose then whats the difference between readmultvector & readcae? Which one do we use and when? As an engineer myself, I tried to break it down based on 2 key factors below: 1. Syntax differences (Ease of Use) 2. Speed/Performance Attached is the paper i wrote about the same with example. Hope this helps users to pick the right command for their tasks. Happy coding!! Thanks, Manoj kandukuri readmultvector_readcae_why_are_they_2.pdf
5. 1 like

## points data

In the newer versions MVD is included in HyperMesh as an astardard tool. You will get an Excel report in the end, showing the percentage of match and more details. https://altairhyperworks.com/product/model-verification-director#:~:text=Altair's%20Model%20Verification%20Director%20(MVD,of%20the%20simulation%20life%20cycle.
6. 1 like

## points data

If you know surface ID, you can select points by: hm_createmark points 1 "by surface" \$surf_id
7. 1 like

## points data

Answering your question: you could select the points and use hm_getvalue to retrieve its info. hm_getvalue points id=4 dataname=x -25 As a important side note: There are at least 2 tools already built in HM for checking and comparing CADxFE. If you Ctrl+F and type 'comparison' you will find this one. Another ore complete option is called MVD (Model Verification Director) and can be accessed in the Parts Browser. (more info in the help)
8. 1 like

## What can I do for "`FMIConnector:-CreateArchive`. Error: "

@João Marabisa Now it worked! I was missing the components in the bottom, like you've showed in your screen. Thank you so much!
9. 1 like

## Non-linear punching simulation exploding

Maybe in your problem also we could try N2S contact. Your mesh size is too different between master and slaves. It might cause some issues in detecting contact properly. I believe N2S with FINITE/CONSLI might give better results. But we need to test.
10. 1 like

## Non-linear punching simulation exploding

i forgot to mention thath in your case, as there's lots of sliding in the contact region, it is recommended to use TRACK in contact groups, as FINITE or CONTINUOUS SLIDING as there is a lot of changing in contact pairs. Oherwise, contact pairs are not recalculated through the analysis (SMALL SLIDING). Also, when running a NL model for the first tiem, i would recommned using PARAM,NLMON,DISP as it saves a _nl.H3D file that can be opened in HV in real time, and checking critical areas for convergence.
11. 1 like

## follower force

please, take a look at this video at youtube..it is very similar.
12. 1 like

## Non-linear punching simulation exploding

do you have the out file? it is always nice to take a look at it first.
13. 1 like

## follower force

you should start from the CAD geometry or try to draw the geometry in HM, first of all. Once you have the geometry, you can start building the 3D mesh (using tetramesh or solidmap, depending on the complexity). The 'x' that you see is a rigid element (RBE2 in OptiStruct), that can be created in 1D>rigids once you have the mesh, amterials, and properties, you create a load collector, and going in forces you For the follower force, you will create a force otf type FORCE1 and select 2 nodes on your mesh as reference for the direction. So once you enable PARAM,FFLOWER,YES, your force will follow these 2 nodes. This is all covered in the documentation unbder the tutoria for OptiStruct OS-T: 1510 Follower Loads, Nonlinear Adaptive Criteria, and Nonlinear Intermediate Results
14. 1 like

## Card that relates design variables

for size optimization problems you could create dervar links combining 2 or more design variables, by creating some relation using them. with desvar link you could say for example: t1 = 2*t2 It can be created as DESVAR LINK1 or 2. 1 is linear relation, and 2 you can create an equation using DEQUATN. Try looking at them in the Help for OptiStruct. The other way of performing this kind of relation is though a design constraint, just like any other optimization constraint., You can create a response of type 'function' (DRESP2) and assign it with an equation (DEQATN). Then you assign the design variables? (t1, t2, t3...) and create an expression, such as 'F(t1,t2)=abs(t1-t2)'. Having this relation you could specify a dconstraint and limit the difference to some value, using upper or lower bounds.
15. 1 like

## Non-linear punching simulation exploding

i'm wondering what material are you using and which units. Looking at your material, the LIMIT1 under MATS1 is only 100. Your Young modulus is extremely high compared to that. So at the minimum touch, there is plasticity already. Besides checking these values I would recommend you to impose a control in maximum increment DTMAX in NLADAPT. As there seems to be lots of plasticity, a tighter increment control might be needed. Also consider changing the NLPARM to NLPARM(LGDISP) if large strains are expected.
16. 1 like

## Read M, K and C matrices and compute energy of each DOF

Hello, community. @Kosuke IKEDA and I recently worked on a DMIGPCH reader for OML. It is an output file from OptiStruct with reduced M (mass), K (stiffness) and C (damping) matrices that can be fed into external data files to be used in subsequent analyses. These are ASCII files whose tags MAAX, KAAX and BAAX identify what is data from mass, stiffness and damping, respectively: Each value represents the nodal real value of the matrix. With it, it's possible to compute the eigen values and energy distribution of each degree of freedom. Regards, Roberta stc_readDMIGPCH_rev3.oml forum_sample_AX.pch
17. 1 like

## Digitize plots in images

This is absolutely awesome, Roberta! Thank you for sharing! Best Christian
18. 1 like

## No buckling modes found in an optimization process

@Joao OptiStruct uses a mechanism called Screening that filters out the design constraints in optimization depending on how far they are from the boundaries (targets). In your case, probably the bucklinf factors are more tha 50% above your target, and that's why OS doesn't take them into account in the very beginning. As the optimization progresses, the constraints are closer from the target values, thus OS starts "looking at them" back again.
19. 1 like

## Linear Buckling Analysis

just highlighting a couple enhancements on this, extracted from RElease notes. OS 2019.0 brought RIKS method for helping these unstable snap-trhu behavior. OS 2019.1 Imperfection An imperfection can be applied to the model. Note: Only supported for Nonlinear Analysis. The IMPERF Bulk Data and Subcase Entries can be used to apply an imperfection. An imperfection can be introduced into the model in the following ways: TYPE=H3DRES on IMPERF Bulk Data: An h3d file is referenced which contains previously completed analysis results. TYPE=GRID on IMPERF Bulk Data: The perturbation of grids can be directly applied. OS 2019.0 Snap-thru with Arc-Length method The Arc-Length method has been implemented to solve snap-thru problems in nonlinear analysis. Solution control is available thru the NLPCI Bulk Entry and three methods (Crisfield, Riks, and Modified Riks).
20. 1 like

## Unable to convert to penetration (intersection)

Hi, Can you turn off "Near by surfaces not overlapping" and "Penetrating surfaces" check box and then try convert to overlap? It will work. Refer the attached video for your reference. Also, attached a sample model used in the video. Convert_Overlap_Penetration.mp4 Intersection.gda
21. 1 like

## Particle Spacing in nFX Tools

Hi, Particle spacing is the distance between adjacent particles in the global coordinate. The particles are uniformly distributed along the global XYZ axis. This spacing is used when generating the particles for stationary parts, moving parts and the fluid regions. The above information I took from SimLab help page. After opening the "1 Click SPH creation" tool, press F1 will take you to the help page about this tool. If you are using SimLab 2019.3 or later version, we have introduced unit system in SimLab. Refer the attached image. If you are using older versions of SimLab, Specify the value for particle spacing based on model units. For example, if the model imported in Meter, then specify the particle spacing value in Meters. You have to make sure that the units are consistent.
22. 1 like

## tcl command not exiting

Hi, can you trying adding -nobg hv -b -nobg -tcl Image_Capture1.tcl example.modl example.res
23. 1 like

## Unintentional Cross-coupling

Hi, Model two(one Tx and Rx) horn antenna in different angle say one is in x-direction and other is in -x direction with certain distance by placing the ground. Terminate one antenna by load and excite other antenna by wire port. S-parameters can be found Thank you
24. 1 like

## Geometry Explode View & X-Section

In fact it depends to you work and to your working method. With more than 20 years of FEA I never need this feature
25. 1 like

## Create N instances of a component and connect ports with a loop

Hello community, if you like to instantiate a certain number of a model/class/component and connect the ports with a for-loop you can do it like in the picture below: In this example a specified number of the "HeatedPipe" component is created. One for-loop is connecting the flow ports and the other one is connecting the heat ports. regards Nils RadiatorSimple.zip
26. 1 like

## Can't Boolean-Combine PolyNURBSFit and non-design space parts

Hi Simonebellini, Could you please share the file with me.
27. 1 like

## Top Use Cases

Saving Material Without Performance Loss Challenge Reducing the weight without loss of usability and strength Optimizing the manufacturing process Solution Injection molding simulation to optimize the part production and to create the fiber orientation for the new designed part Taking into account these results to perform most realistic mechanical simulation Results Significant material and cost savings due to optimized geometry Faster and more economic production process
28. 1 like

## Top Use Cases

Challenge Detect weak areas due to weld lines Estimate the influence on the part strength Solution Converse mapping capabilities in order to assign weld line areas and flow angle to the mechanical model Results Optimized manufacturing process Knowledge of local varying component strength
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