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I'm encountering some issues while trying to automate certain manipulations across different .k files. Here's the method I've developed to achieve my goal:Import the STL files.Use element generation to create voxel contours from the STL files.Mesh tetrahedra within the voxel boundaries.I'm currently stuck at the voxel elements generation step. While the manual process works well, I'm facing difficulties when trying to automate it using command lines. Specifically, the elgenerate command doesn't seem to accept the element generation.----elgenerate solid voxel parts 1 88000265pa bysize 1 1 1 outlineonly cubevoxel obbboundelgenerate accept---When executing these commands through the command line, the process stops at the visualization and voxel generation step. The expected outcome, which is creating a new part, isn't happening.Could someone please assist me in resolving this issue?Issue with Command Line Execution: No Part Generation:This is the expected next step by 'elgenerate accept' which creates a new part (not happening when using the command lines...):
Hello, I am setting up a FSI simulation in LS dyna using the S-ALE solver. I would like to set up a coarse mesh for the fluid domain and refine it dynamically, near the Lagrangian structure to which the fluids are coupled(*CONSTRAINED_LAGRANGE_IN_SOLID).The sphere inside is a lagrangian structure (PID=1). I want the S-ALE mesh elements close to the sphere to be refined dynamically. I have tried the following using *CONTROL_REFINE_ALE keycardI have set up a Pressure based refinement condition with the Reference value as 0 so that all ALE solid elements that are coupled to the lagrangian sphere can be refined.MMSID=3 is a MULTI_MATERIAL_GROUP_SET containing all the MM groups in the model (Air and Water). I get the following error when including this keycard to refine the ALE mesh, whereas the solution works fine without the *CONTROL_REFINE_ALE keycard. Could someone please explain if there is a possible solution to this error or if there are mistakes in my model definition.Thanks in advance!
Abhemanyu Palaniswamy Chandrasekaran
April 15, 2024
Hello,I am performing drop test on a FRP wrapped RC beam. When I had input properties of the material T300/5208 in the usual manner it prompted error. So I attempted to input the data in the following manner; but still it shows me error. What part am I getting wrong? How can I fix this error?Regards,Prasad.
I am simply looking to simulate the contact between two rings made of beam elements using the thickness of the beams as the contact "surface". The manual mentions beam-to-beam contact:*CONTACT_AUTOMATIC_GENERAL is asingle surface contact similar to *CONTACT_AUTOMATIC_SINGLE_SURFACEthat also includes treatment of beam-to-beam contact and in doing so,checks along the entire length of the beams for penetration.But my rings don't see each other with this turned on:*CONTACT_AUTOMATIC_GENERAL_ID$# cid title 1 $# surfa surfb surfatyp surfbtyp saboxid sbboxid sapr sbpr 0 1 2 2 0 0 0 0$# fs fd dc vc vdc penchk bt dt 0.0 0.0 0.0 0.0 0.0 0 0.01.00000E20$# sfsa sfsb sast sbst sfsat sfsbt fsf vsf 1.0 1.0 0.0 0.0 1.0 1.0 1.0 1.0
Hi everyone,I am getting an error message when running my simulations. the problem with this error is that first it happens randomly in different time steps and I could not find any solid clue what it might be related to.Here are some details: -error message:"forrtl: severe (157): Program Exception - access violation" since it looked to me like a file write access error from Windows, in one of the cases i just copied my .K file into another folder and it resolved.for this file that i am having trouble with, it used to happen after the 18th time point but after copying the file it is now thrown at the 3rd time point.in my previous files, sometimes i find extra space in the .k file, and correcting it resolves the issue. I writing to see if anyone has any idea what it might be or where i can look to figure it out. Thank you for your response in advance.
As I refine my mesh I keep getting the error in the title. This is run on a HPC. As I refine my mesh I get this problem. My coarser meshes run but the solutions are not satisfactory. I have a spherical charge of 4g with a 325 mm stand-off distance in free air. Below are some traces which are equidistant from the charge mass but taken in different directions. The air block size is a cube with a side length 500 mm and have three planes of symmetry. I start the traces at 0.2 ms. The pressure is in MPa.
Hello, I am trying to use lstasc for topology optimization. I just started to work on manual examples. Still, however when I tried to solve beam example ( file provided by lsdyna manual examples) it just don't start to running and this is same for every case. since its a provided example the constraints and other stuff already defined so ı just click the run. Still, the iterations never starting and I cant see the job on the job status window. I already tried to use command line with "C:\Program Files\ANSYS Inc\v232\ansys\bin\winx64\lsdyna_dp.exe" Also when I checked the ansys license manager it does not even use the dyna license while it shows running.
I am trying to simulate a blade cutting through a pipe. However, I am getting a solver error saying that the energy error is too large. I am very new to this software, so can someone explain to me how to fix this issue.
Whenever I import the .step file into explicit dynamics using discovery, my model (a structure and a wall) only loads the wall. I have copied a picture of the cross section without the wall. This cross section continues for about 1770mm. The .step file is 130 MB. Is there a way to somehow make this model work as it is?pc spec:Processor 13th Gen Intel(R) Core(TM) i9-13900K 3.00 GHzInstalled RAM 32.0 GB (31.7 GB usable)GPU: nvidia rtx 4090ssd: samsung 850 pro
https://github.com/Ice-Citron/FEA-Physics_IA/blob/main/First%20Runnable/final_read%20-%202.khttps://github.com/Ice-Citron/FEA-Physics_IA/tree/main/First%20Runnable/Second%20Runnable I am trying to simulate a railgun of a particular topology and size for my college Physics Coursework. I am very new to LS-Dyna, but has managed to get used to LS-Dyna's structure and everything, etc. I am using the railgun exemplar as my guide. On very above of this post, these 2 links are my GitHub repo which contains the 2 variants of keyword file I created, which are based on the railgun exemplar on LS-DYNA examples: https://lsdyna.ansys.com/em-railgun/#animated-resultThe issue that I am facing is this:I am using the exact same settings as the exemplar, as far as I am concerned. The only difference between my .k file and the exemplar is that I am using a different solid mesh for my railgun, as I will be using a different topology soon after. My mesh is created from .STEP file exported from fusion 360, which I then selected one of the faces, and then mesh it to 1.2mm with auto-mesher, and then used element generation to generate the rest of the component using shell offset to solid shell. I checked the contact of both files, as in penetration and contact edges. The exemplar itself seems to also have penetration + contact edges natively too, and its simulation works despite the initial penetrations. My version is the second one, and even when I try to remove the penetrations, etc. The same error output file is produced, which thus I in a way think penetration isn't the issue here with FEM-BEM solver being unable to converge?I hope someone is willing to attempt to download my .k source files from my git repo, and then try and see if they can solve it, so that it runs like the one in the exemplar.
Hello,I'm using the SPH method in LS-DYNA to simulate the ballistic high-velocity impact problem. I find that the strain energy plot is not consistent with temperature change and pressure plots.Specifically, the material I used for the projectile and target plate are both defined by *MAT_015 (*MAT_JOHNSON_COOK). In the post-processing, the strain energy plot for the very first time frame is shown:It is wired that the maximum strain energy starts at the middle of the target plate when the projectile first contacts it. There is almost no deformation and stress change; the shock wave has just begun. So, there is no reason that the strain energy in the middle becomes the maximum at first.But for the temperature change plot (history variable #5 for *MAT_015_JOHNSON_COOK) and pressure plot, it can be easily seen that the maximum points in the first time frame starts at the contact point.All the results above are calculated by using the R 13.0 solver. Besides, I try to use the latest solver to test the result but for the same job in the R 14.0 solver, the job will be stuck at some point and cannot be fully calculated. So, I changed different mesh sizes and solver with the same setup for other conditions (initial velocity, material properties, etc.), and the result of the strain energy plot has the same problem:The result above is calculated by the R 14.0 solver with coarse mesh.Coincidentally, the maximum point starts at the 16th layer of the SPH plate. I don't know if this error comes from numerical methods or comes from visualization errors. Could help to explain or tell me how to find the correct strain energy distribution in the whole plate? Best,Rong
Hello,How to implement higher order scheme in LS Dyna CESE solver described in the following link.https://link.springer.com/chapter/10.1007/978-981-99-0876-9_5Is the default option in CESE solver first order or second order method ?Regards,Atish
Hello,I want to use the Linux based HPC server of my university. I tried it but it doesn't work. I used the button "write input file" for creating a input file for the HPC. My LS-Dyna model made a .key file and my explicit dynamic model (which i combined with a static structural calculation) made a .dat file. After loading these files up an submitting the job, i get after 30-60 seconds some error messages.LS-DynaExplicit dynamicsDoes anyone have a clue what i'm doing wrong? Thank you!
Hello All., I really need help in solving this problem. My aim is to find the max velocity of a bullet. My initial conditions are pressure at 10PSI at back surface of bullet. Cylinder/barrel is fixed. contact is set to frictional. standard earth gravity is given.Initially i tried simulation at lower time frames (0.0001) i got a result with increasing velocity. as on when i crease the time frames, bullet velocity also increases.How do i find out max velocity in this case. will increasing more time frame gives me the desired result??. have tested this practically and found the desired bulled reaches 8m( horizontal) @1.5 sec when fired at 90PSI. i wanted to validate the same in ANSYS. I have set this problem in transient structural.
I was using *parameter keyword in Ls Pre-post for optimizing a sheet metal forming process in Ls Opt. I am not able to refer the variable to the data point of a curve (Define--->Curve). How can I input a curve data point from Pre-post to Ls opt as an input parameter?
I am trying to permanently connect a shell with an irregular shape (made of steel) to another rigid shell in LS-Dyna.Can someone help me?I have tried different contact types, but did not manage to solve it.Thanks
I'm using a Workbench Ls-dyna (student account).I want to set a material on each plane.But there is no few material model, equation in the engineering data.I want to add the material belowCopper- Steinberg material model- Gruneisen equationSteel- John-Cook modelShaped-charge Explosive- Mat_High_Explosive_Burn material- JWL equationERA Explosive- Ignition-and-growh-of-reaction-in-HE equationBut i couldn't find a Steinberg, Mat_High_Explosive_Burn, Ignition-and-growh-of-reaction-in-HEHow can i add it?(I'm a beginner)
I'm encountering some issues while trying to automate certain manipulations across different .k files. Here's the method I've developed to achieve my goal:Import the STL files.Use element generation to create voxel contours from the STL files.Mesh tetrahedra within the voxel boundaries.I'm currently stuck at the voxel elements generation step. While the manual process works well, I'm facing difficulties when trying to automate it using command lines. Specifically, the elgenerate command doesn't seem to accept the element generation.----elgenerate solid voxel parts 1 88000265pa bysize 1 1 1 outlineonly cubevoxel obbboundelgenerate accept---When executing these commands through the command line, the process stops at the visualization and voxel generation step. The expected outcome, which is creating a new part, isn't happening.Could someone please assist me in resolving this issue?Issue with Command Line Execution: No Part Generation:This is the expected next step by 'elgenerate accept' which creates a new part (not happening when using the command lines...):
Hello, I am setting up a FSI simulation in LS dyna using the S-ALE solver. I would like to set up a coarse mesh for the fluid domain and refine it dynamically, near the Lagrangian structure to which the fluids are coupled(*CONSTRAINED_LAGRANGE_IN_SOLID).The sphere inside is a lagrangian structure (PID=1). I want the S-ALE mesh elements close to the sphere to be refined dynamically. I have tried the following using *CONTROL_REFINE_ALE keycardI have set up a Pressure based refinement condition with the Reference value as 0 so that all ALE solid elements that are coupled to the lagrangian sphere can be refined.MMSID=3 is a MULTI_MATERIAL_GROUP_SET containing all the MM groups in the model (Air and Water). I get the following error when including this keycard to refine the ALE mesh, whereas the solution works fine without the *CONTROL_REFINE_ALE keycard. Could someone please explain if there is a possible solution to this error or if there are mistakes in my model definition.Thanks in advance!
Abhemanyu Palaniswamy Chandrasekaran
April 15, 2024
Hello,I am performing drop test on a FRP wrapped RC beam. When I had input properties of the material T300/5208 in the usual manner it prompted error. So I attempted to input the data in the following manner; but still it shows me error. What part am I getting wrong? How can I fix this error?Regards,Prasad.
I am simply looking to simulate the contact between two rings made of beam elements using the thickness of the beams as the contact "surface". The manual mentions beam-to-beam contact:*CONTACT_AUTOMATIC_GENERAL is asingle surface contact similar to *CONTACT_AUTOMATIC_SINGLE_SURFACEthat also includes treatment of beam-to-beam contact and in doing so,checks along the entire length of the beams for penetration.But my rings don't see each other with this turned on:*CONTACT_AUTOMATIC_GENERAL_ID$# cid title 1 $# surfa surfb surfatyp surfbtyp saboxid sbboxid sapr sbpr 0 1 2 2 0 0 0 0$# fs fd dc vc vdc penchk bt dt 0.0 0.0 0.0 0.0 0.0 0 0.01.00000E20$# sfsa sfsb sast sbst sfsat sfsbt fsf vsf 1.0 1.0 0.0 0.0 1.0 1.0 1.0 1.0
Hi everyone,I am getting an error message when running my simulations. the problem with this error is that first it happens randomly in different time steps and I could not find any solid clue what it might be related to.Here are some details: -error message:"forrtl: severe (157): Program Exception - access violation" since it looked to me like a file write access error from Windows, in one of the cases i just copied my .K file into another folder and it resolved.for this file that i am having trouble with, it used to happen after the 18th time point but after copying the file it is now thrown at the 3rd time point.in my previous files, sometimes i find extra space in the .k file, and correcting it resolves the issue. I writing to see if anyone has any idea what it might be or where i can look to figure it out. Thank you for your response in advance.
As I refine my mesh I keep getting the error in the title. This is run on a HPC. As I refine my mesh I get this problem. My coarser meshes run but the solutions are not satisfactory. I have a spherical charge of 4g with a 325 mm stand-off distance in free air. Below are some traces which are equidistant from the charge mass but taken in different directions. The air block size is a cube with a side length 500 mm and have three planes of symmetry. I start the traces at 0.2 ms. The pressure is in MPa.
Hello, I am trying to use lstasc for topology optimization. I just started to work on manual examples. Still, however when I tried to solve beam example ( file provided by lsdyna manual examples) it just don't start to running and this is same for every case. since its a provided example the constraints and other stuff already defined so ı just click the run. Still, the iterations never starting and I cant see the job on the job status window. I already tried to use command line with "C:\Program Files\ANSYS Inc\v232\ansys\bin\winx64\lsdyna_dp.exe" Also when I checked the ansys license manager it does not even use the dyna license while it shows running.
I am trying to simulate a blade cutting through a pipe. However, I am getting a solver error saying that the energy error is too large. I am very new to this software, so can someone explain to me how to fix this issue.
Whenever I import the .step file into explicit dynamics using discovery, my model (a structure and a wall) only loads the wall. I have copied a picture of the cross section without the wall. This cross section continues for about 1770mm. The .step file is 130 MB. Is there a way to somehow make this model work as it is?pc spec:Processor 13th Gen Intel(R) Core(TM) i9-13900K 3.00 GHzInstalled RAM 32.0 GB (31.7 GB usable)GPU: nvidia rtx 4090ssd: samsung 850 pro
https://github.com/Ice-Citron/FEA-Physics_IA/blob/main/First%20Runnable/final_read%20-%202.khttps://github.com/Ice-Citron/FEA-Physics_IA/tree/main/First%20Runnable/Second%20Runnable I am trying to simulate a railgun of a particular topology and size for my college Physics Coursework. I am very new to LS-Dyna, but has managed to get used to LS-Dyna's structure and everything, etc. I am using the railgun exemplar as my guide. On very above of this post, these 2 links are my GitHub repo which contains the 2 variants of keyword file I created, which are based on the railgun exemplar on LS-DYNA examples: https://lsdyna.ansys.com/em-railgun/#animated-resultThe issue that I am facing is this:I am using the exact same settings as the exemplar, as far as I am concerned. The only difference between my .k file and the exemplar is that I am using a different solid mesh for my railgun, as I will be using a different topology soon after. My mesh is created from .STEP file exported from fusion 360, which I then selected one of the faces, and then mesh it to 1.2mm with auto-mesher, and then used element generation to generate the rest of the component using shell offset to solid shell. I checked the contact of both files, as in penetration and contact edges. The exemplar itself seems to also have penetration + contact edges natively too, and its simulation works despite the initial penetrations. My version is the second one, and even when I try to remove the penetrations, etc. The same error output file is produced, which thus I in a way think penetration isn't the issue here with FEM-BEM solver being unable to converge?I hope someone is willing to attempt to download my .k source files from my git repo, and then try and see if they can solve it, so that it runs like the one in the exemplar.
Hello,I'm using the SPH method in LS-DYNA to simulate the ballistic high-velocity impact problem. I find that the strain energy plot is not consistent with temperature change and pressure plots.Specifically, the material I used for the projectile and target plate are both defined by *MAT_015 (*MAT_JOHNSON_COOK). In the post-processing, the strain energy plot for the very first time frame is shown:It is wired that the maximum strain energy starts at the middle of the target plate when the projectile first contacts it. There is almost no deformation and stress change; the shock wave has just begun. So, there is no reason that the strain energy in the middle becomes the maximum at first.But for the temperature change plot (history variable #5 for *MAT_015_JOHNSON_COOK) and pressure plot, it can be easily seen that the maximum points in the first time frame starts at the contact point.All the results above are calculated by using the R 13.0 solver. Besides, I try to use the latest solver to test the result but for the same job in the R 14.0 solver, the job will be stuck at some point and cannot be fully calculated. So, I changed different mesh sizes and solver with the same setup for other conditions (initial velocity, material properties, etc.), and the result of the strain energy plot has the same problem:The result above is calculated by the R 14.0 solver with coarse mesh.Coincidentally, the maximum point starts at the 16th layer of the SPH plate. I don't know if this error comes from numerical methods or comes from visualization errors. Could help to explain or tell me how to find the correct strain energy distribution in the whole plate? Best,Rong
Hello,How to implement higher order scheme in LS Dyna CESE solver described in the following link.https://link.springer.com/chapter/10.1007/978-981-99-0876-9_5Is the default option in CESE solver first order or second order method ?Regards,Atish
Hello,I want to use the Linux based HPC server of my university. I tried it but it doesn't work. I used the button "write input file" for creating a input file for the HPC. My LS-Dyna model made a .key file and my explicit dynamic model (which i combined with a static structural calculation) made a .dat file. After loading these files up an submitting the job, i get after 30-60 seconds some error messages.LS-DynaExplicit dynamicsDoes anyone have a clue what i'm doing wrong? Thank you!
Hello All., I really need help in solving this problem. My aim is to find the max velocity of a bullet. My initial conditions are pressure at 10PSI at back surface of bullet. Cylinder/barrel is fixed. contact is set to frictional. standard earth gravity is given.Initially i tried simulation at lower time frames (0.0001) i got a result with increasing velocity. as on when i crease the time frames, bullet velocity also increases.How do i find out max velocity in this case. will increasing more time frame gives me the desired result??. have tested this practically and found the desired bulled reaches 8m( horizontal) @1.5 sec when fired at 90PSI. i wanted to validate the same in ANSYS. I have set this problem in transient structural.
I was using *parameter keyword in Ls Pre-post for optimizing a sheet metal forming process in Ls Opt. I am not able to refer the variable to the data point of a curve (Define--->Curve). How can I input a curve data point from Pre-post to Ls opt as an input parameter?
I am trying to permanently connect a shell with an irregular shape (made of steel) to another rigid shell in LS-Dyna.Can someone help me?I have tried different contact types, but did not manage to solve it.Thanks
I'm using a Workbench Ls-dyna (student account).I want to set a material on each plane.But there is no few material model, equation in the engineering data.I want to add the material belowCopper- Steinberg material model- Gruneisen equationSteel- John-Cook modelShaped-charge Explosive- Mat_High_Explosive_Burn material- JWL equationERA Explosive- Ignition-and-growh-of-reaction-in-HE equationBut i couldn't find a Steinberg, Mat_High_Explosive_Burn, Ignition-and-growh-of-reaction-in-HEHow can i add it?(I'm a beginner)
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