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Hello,ANSYS fluent have pressure based or density based solver and implicit and explicit scheme.I want to understand whether CESE method pressure based / density based solver with implicit or explicit scheme?Regards,Atish
I am learning the SPG method to simulate drilling,but I cannot get K file in this website(Drilling | CMM Group in LSTC (lstc-cmmg.org)).Could you please provide the K file of this case? Thank you very much!
I applied rotational angle load using remote displacement in Workbench/LS-DYNA, and the moment reaction could not be extracted from the result? How to extract the torque reslut in LS-DYNA?
I want to proceed with the analysis of the ball hitting the glass and breaking it. The photo below shows the plate made of aluminum using 18.MAT_POWER_LAW_PLASTICITY. I want to change the aluminum material to glass material. I want to use 280.MAT_GLASS. Can you give me an example? What I am using is the free version, LS-PrePost.
Hi all!I am looking for the Fortran Complier (Intel Parallel Studio XE any version). Could I please request installation package for any version including and above 2017 version, please!Many thanks,Kyle
I want to open my LS-DYNA results (in d3plot format) in Ansys workbench. I know I can open it on LS-Prespost, but Ansys visualization gives me some options that are not available in LS-Prespost. How should I do it?
I have a simulation where I have a steel ball (radius of 10 mm, rigid steel material) that collides into a PLA plate (20mm thick) at 400 m/s. I have a automatic_surface_to_surface contact. However, the ball simply phases through the PLA and doesn't show any deformation, but it does show stresses as if it hit.
Hello everyone,I'm trying to simulate an explosion with ALE contact (type Lagrangian_in_solid, ALE_Multi_Material_Group) on a simple mesh box. But I get a strange error message when I start a job:*** Warning 21292 (STR+1292) Load curve ID 37 of *MAT_SIMPLIFIED_RUBBER/FOAM ID 1 covers only the tensile range. It should include both the tensile & compressive range to ensure it describes the complete range of loading *** Warning 21293 (STR+1293) The abscissa for load curve ID 38 used for material ID 181 is decreasing. This is not permitted and may result in strange behavior.I had already used mat_181 with the same stress-strain curves without control_ALE, and it worked. Do you have any idea how I can solve this problem? When I start a job with a simple curve in the mat_181 and no table to define the load curve. I don't get this error message.Thank you for your understanding.
Hi,I encountered some difficulties plotting force vectors on Ls-Prepost. I want to plot all the contact force on the master side of the contact. I have nodal force result from NCFORCE via automatic_node_to_surface, but I didn't find "force" option in vector display section. May I ask for a brief guide on how to do that? Thanks!
Hi everyone,I'm running drop test simulations on explicit dynamics in workbench. I'm simulation an apple falling from a drop height of 2 meters under standard earth gravity. I want to simulate the deformation once the apple lands on the rigid surface.Here are some the challenges I'm facing:1. An apple is not a perfect sphere. How do I include some physical and mechanical properties of the apple e.g.~Equatorial diameter~Polar diameter~Thickness~Shape index~Volume~Curvature radius2. I assumed a perfect sphere for the initial simulations. However, the apple bounced off the rigid structural steel surface like a tennis ball would. How can I overcome this and effectively realize a simulation that depicts normal reaction of the apple in such a scenario3. Change in color depicts change in deformation to a varying extent. However, there is change before the apple hits the surface. What could be the issue and how can I overcome it.
Hello all!For some reason I can't understand, some of my simulations suddenly terminate with no useful error message using the MPP solver. My solution to this is restarting the job, but no d3dump files were generated.I found the *DATABASE_BINARY_D3DUMP option, but I am a little unsure what value to use in CYL to write d3dump files. How can I determine an appropriate value of CYL? I guess I should divide the total time by a certain value associate with the timestep? Is there a way to force ls dyna to actually write the default d3dumpfiles after an error termination? I hope you can please help me. Thanks, Andres
I am doing an analysis of drag force simulation on a blast loaded fabric roof. In the model, the supporting frame consists of curved beams, which is the supporting frame of fabric canopy. While simulating, the fabric roof is getting detached away from the beams and showing improrper pattern of deformation. Can I please know whether it is required to define any contact keywords or what could be the mistake in the modelling in LS DYNA?
Hello, I am doing perforation test, in which due to symmetry I modeled Projectile and target both as 2d-axisymmetric, but now when I click on geometry of target and try to assigne stiffness behaviour as rigid I am unable to do it. It is showing yellow colour(means not assigned). What to do in this case. I have attached image of it.Thank you
I really use the combination of S-ALE and SPG-FEM to do blast simulation, so I would like to ask you the following two questions:1, How should I define the contact between different SPG PART? I only found the keyword CONTACT_SPG.2, How should the fluid-solid coupling between S-ALE and SPG, FEM? I use the keyword *ALE_COUPLING_NODAL_PENALTY to build SPG, FEM in a PART LIST to couple with S-ALE, but there is a case of coupling not working.I hope I can get help from everyone, thanks a lot!
Hello,I am a beginner to LS-DYNA. I would like to simulate the wake around a ship moving with a constant velocity by using the ALE method with penalty coupling. I have the following queires to begin with.1. Is ALE method recommended for such simulations involving larger time durations?2. To begin with a simple numerical simulation, I start with a partially submerged cylinder. Would ALE solver be able to capture the effects of viscous drag and boundary layers?3. Are there some recommendations to model the water around a floating body (material properties and equations of state) which would particularly suit this simulation?I am working on my master's thesis regarding ship collisions. I would like to use the ALE method to investigate the collision phenomenon along with the Fluid-Structure Interaction. Is it possible to use a different solver such as the ICFD solver for the initial phase of the ship motion (generating the wake field around the moving ship) and then switch to the ALE solver for the collision simulation.Thanks & RegardsAbhemanyu
Abhemanyu Palaniswamy Chandrasekaran
March 20, 2024
Hello, I'm using the SPH method to simulate a high-speed ballistic impact problem. I want to output the strain energy of the individual particle. I cannot find the strain energy icon in the #History in LS-Prepost, but I find it in the Fringe Component.I can only display the contours of the strain energy, but I don't know how to output these values as XY pairs.Could you show me the steps in detail? Best,Rong
I'm preparing model in ls-dyna for seatbelt analysis. When I try to run a calculation, an error occures. Weird, because there are no beam elements with those id.Thanks for help.
Hi, I am using shell elements for an I section and applying blast loading on its weak axis. I couldnt able to establish proper contact between flange and web. Any suggestions which contact is more suitable! I tried merging nodes but couldnt achieve good results
Hi, I need to automate running simulations and extracting results without manually opening each simulation. I'm using LS-DYNA to model blast loading on steel columns. Can someone provide a solution for this, preferably using MATLAB?
Hello everyone, I got the stress-strain curve of uniaxial compression test of a foam, and used it to build its Ogden material model in the engineering database, as shown in the figure. I used the fitting function of ANSYS to get the parameters of the material formula. When I used it for Droptest emulation, the solver gave me an error and I couldn't figure out why. In addition, I found a rubber 1 material in the engineering database, but it can normally participate in calculation. I couldn't find the reason for my calculation failure. I hope you can help me if you are in the same situation as me, thank you
Hello, I have a question about autodyn. I would like to ask you how autodyn imports external energy deposition. I built a copper cylinder, and then knew the energy deposition corresponding to each point in it. How can I introduce the energy deposition into the cylinder, and then calculate the density pressure after a certain time, etc. I tried to carry out secondary development of autodyn and found that the EXSIE module in the subroutine can import energy deposition, but it only has one input parameter. I don't know how to input it, so I would like to ask for advice. The picture shows the subroutine EXSIEThe picture shows the energy deposition I want to import. The first and second columns are the coordinates, and the third column is the corresponding energy deposition
I want to use the database *DATABASE_TRACER, but the R13 and R14 manuals state, "The option *DATABASE_TRHIST must be active." I can't find how to make it active in the manuals. Can anyone shed light on this?
Hello,I'm using the SPH method in LS-DYNA to simulate the high-speed impact problem (Using a metal ballistic projectile to impact a metal plate). I find that the internal energy is not consistent with different numbers of particles (different meshes) for the plate and the projectile. The results are listed below, which are the coarse mesh (70*70*19=93100 nodes), medium mesh (107*107*28=320572 nodes), and fine mesh (151*151*40=912040 nodes).All the other setups are kept the same for the three cases. As can be seen, the internal energy is not convergent for these cases. For example, the internal energy at 1e-5 s is 2.8e9 (coarse mesh), 3e9 (medium mesh), and 3.5e9 (fine mesh) respectively. These results are calculated by the R 13.0 solver. I also tried to use R 14.0 solver but the results still show a different trend. Even for some cases, the job will stuck at 33% or 46% and I don't know why.I would like to know how LS-DYNA calculates the internal energy and how I can verify it. We know that the internal energy can be divided into two parts. One is the strain energy, which can be calculated by particle strain and stress. The other is heat, which can be calculated by the particle temperature change. For strain energy, I plan to output all the stress and strain of all the particles in each timestep, then I can calculate the increment of strain δε, then time σ, and the total volume and sum, which is the internal energy. For the heat, I plan to output all the temperature change, then times the total mass and specific heat capacity, which is the total heat generated. However, in some cases, I find that the sum of total strain energy calculated and total heat calculated does not equal to the total internal energy directly plotted in *MATSUM. Best,Rong
Hello,ANSYS fluent have pressure based or density based solver and implicit and explicit scheme.I want to understand whether CESE method pressure based / density based solver with implicit or explicit scheme?Regards,Atish
I am learning the SPG method to simulate drilling,but I cannot get K file in this website(Drilling | CMM Group in LSTC (lstc-cmmg.org)).Could you please provide the K file of this case? Thank you very much!
I applied rotational angle load using remote displacement in Workbench/LS-DYNA, and the moment reaction could not be extracted from the result? How to extract the torque reslut in LS-DYNA?
I want to proceed with the analysis of the ball hitting the glass and breaking it. The photo below shows the plate made of aluminum using 18.MAT_POWER_LAW_PLASTICITY. I want to change the aluminum material to glass material. I want to use 280.MAT_GLASS. Can you give me an example? What I am using is the free version, LS-PrePost.
Hi all!I am looking for the Fortran Complier (Intel Parallel Studio XE any version). Could I please request installation package for any version including and above 2017 version, please!Many thanks,Kyle
I want to open my LS-DYNA results (in d3plot format) in Ansys workbench. I know I can open it on LS-Prespost, but Ansys visualization gives me some options that are not available in LS-Prespost. How should I do it?
I have a simulation where I have a steel ball (radius of 10 mm, rigid steel material) that collides into a PLA plate (20mm thick) at 400 m/s. I have a automatic_surface_to_surface contact. However, the ball simply phases through the PLA and doesn't show any deformation, but it does show stresses as if it hit.
Hello everyone,I'm trying to simulate an explosion with ALE contact (type Lagrangian_in_solid, ALE_Multi_Material_Group) on a simple mesh box. But I get a strange error message when I start a job:*** Warning 21292 (STR+1292) Load curve ID 37 of *MAT_SIMPLIFIED_RUBBER/FOAM ID 1 covers only the tensile range. It should include both the tensile & compressive range to ensure it describes the complete range of loading *** Warning 21293 (STR+1293) The abscissa for load curve ID 38 used for material ID 181 is decreasing. This is not permitted and may result in strange behavior.I had already used mat_181 with the same stress-strain curves without control_ALE, and it worked. Do you have any idea how I can solve this problem? When I start a job with a simple curve in the mat_181 and no table to define the load curve. I don't get this error message.Thank you for your understanding.
Hi,I encountered some difficulties plotting force vectors on Ls-Prepost. I want to plot all the contact force on the master side of the contact. I have nodal force result from NCFORCE via automatic_node_to_surface, but I didn't find "force" option in vector display section. May I ask for a brief guide on how to do that? Thanks!
Hi everyone,I'm running drop test simulations on explicit dynamics in workbench. I'm simulation an apple falling from a drop height of 2 meters under standard earth gravity. I want to simulate the deformation once the apple lands on the rigid surface.Here are some the challenges I'm facing:1. An apple is not a perfect sphere. How do I include some physical and mechanical properties of the apple e.g.~Equatorial diameter~Polar diameter~Thickness~Shape index~Volume~Curvature radius2. I assumed a perfect sphere for the initial simulations. However, the apple bounced off the rigid structural steel surface like a tennis ball would. How can I overcome this and effectively realize a simulation that depicts normal reaction of the apple in such a scenario3. Change in color depicts change in deformation to a varying extent. However, there is change before the apple hits the surface. What could be the issue and how can I overcome it.
Hello all!For some reason I can't understand, some of my simulations suddenly terminate with no useful error message using the MPP solver. My solution to this is restarting the job, but no d3dump files were generated.I found the *DATABASE_BINARY_D3DUMP option, but I am a little unsure what value to use in CYL to write d3dump files. How can I determine an appropriate value of CYL? I guess I should divide the total time by a certain value associate with the timestep? Is there a way to force ls dyna to actually write the default d3dumpfiles after an error termination? I hope you can please help me. Thanks, Andres
I am doing an analysis of drag force simulation on a blast loaded fabric roof. In the model, the supporting frame consists of curved beams, which is the supporting frame of fabric canopy. While simulating, the fabric roof is getting detached away from the beams and showing improrper pattern of deformation. Can I please know whether it is required to define any contact keywords or what could be the mistake in the modelling in LS DYNA?
Hello, I am doing perforation test, in which due to symmetry I modeled Projectile and target both as 2d-axisymmetric, but now when I click on geometry of target and try to assigne stiffness behaviour as rigid I am unable to do it. It is showing yellow colour(means not assigned). What to do in this case. I have attached image of it.Thank you
I really use the combination of S-ALE and SPG-FEM to do blast simulation, so I would like to ask you the following two questions:1, How should I define the contact between different SPG PART? I only found the keyword CONTACT_SPG.2, How should the fluid-solid coupling between S-ALE and SPG, FEM? I use the keyword *ALE_COUPLING_NODAL_PENALTY to build SPG, FEM in a PART LIST to couple with S-ALE, but there is a case of coupling not working.I hope I can get help from everyone, thanks a lot!
Hello,I am a beginner to LS-DYNA. I would like to simulate the wake around a ship moving with a constant velocity by using the ALE method with penalty coupling. I have the following queires to begin with.1. Is ALE method recommended for such simulations involving larger time durations?2. To begin with a simple numerical simulation, I start with a partially submerged cylinder. Would ALE solver be able to capture the effects of viscous drag and boundary layers?3. Are there some recommendations to model the water around a floating body (material properties and equations of state) which would particularly suit this simulation?I am working on my master's thesis regarding ship collisions. I would like to use the ALE method to investigate the collision phenomenon along with the Fluid-Structure Interaction. Is it possible to use a different solver such as the ICFD solver for the initial phase of the ship motion (generating the wake field around the moving ship) and then switch to the ALE solver for the collision simulation.Thanks & RegardsAbhemanyu
Abhemanyu Palaniswamy Chandrasekaran
March 20, 2024
Hello, I'm using the SPH method to simulate a high-speed ballistic impact problem. I want to output the strain energy of the individual particle. I cannot find the strain energy icon in the #History in LS-Prepost, but I find it in the Fringe Component.I can only display the contours of the strain energy, but I don't know how to output these values as XY pairs.Could you show me the steps in detail? Best,Rong
I'm preparing model in ls-dyna for seatbelt analysis. When I try to run a calculation, an error occures. Weird, because there are no beam elements with those id.Thanks for help.
Hi, I am using shell elements for an I section and applying blast loading on its weak axis. I couldnt able to establish proper contact between flange and web. Any suggestions which contact is more suitable! I tried merging nodes but couldnt achieve good results
Hi, I need to automate running simulations and extracting results without manually opening each simulation. I'm using LS-DYNA to model blast loading on steel columns. Can someone provide a solution for this, preferably using MATLAB?
Hello everyone, I got the stress-strain curve of uniaxial compression test of a foam, and used it to build its Ogden material model in the engineering database, as shown in the figure. I used the fitting function of ANSYS to get the parameters of the material formula. When I used it for Droptest emulation, the solver gave me an error and I couldn't figure out why. In addition, I found a rubber 1 material in the engineering database, but it can normally participate in calculation. I couldn't find the reason for my calculation failure. I hope you can help me if you are in the same situation as me, thank you
Hello, I have a question about autodyn. I would like to ask you how autodyn imports external energy deposition. I built a copper cylinder, and then knew the energy deposition corresponding to each point in it. How can I introduce the energy deposition into the cylinder, and then calculate the density pressure after a certain time, etc. I tried to carry out secondary development of autodyn and found that the EXSIE module in the subroutine can import energy deposition, but it only has one input parameter. I don't know how to input it, so I would like to ask for advice. The picture shows the subroutine EXSIEThe picture shows the energy deposition I want to import. The first and second columns are the coordinates, and the third column is the corresponding energy deposition
I want to use the database *DATABASE_TRACER, but the R13 and R14 manuals state, "The option *DATABASE_TRHIST must be active." I can't find how to make it active in the manuals. Can anyone shed light on this?
Hello,I'm using the SPH method in LS-DYNA to simulate the high-speed impact problem (Using a metal ballistic projectile to impact a metal plate). I find that the internal energy is not consistent with different numbers of particles (different meshes) for the plate and the projectile. The results are listed below, which are the coarse mesh (70*70*19=93100 nodes), medium mesh (107*107*28=320572 nodes), and fine mesh (151*151*40=912040 nodes).All the other setups are kept the same for the three cases. As can be seen, the internal energy is not convergent for these cases. For example, the internal energy at 1e-5 s is 2.8e9 (coarse mesh), 3e9 (medium mesh), and 3.5e9 (fine mesh) respectively. These results are calculated by the R 13.0 solver. I also tried to use R 14.0 solver but the results still show a different trend. Even for some cases, the job will stuck at 33% or 46% and I don't know why.I would like to know how LS-DYNA calculates the internal energy and how I can verify it. We know that the internal energy can be divided into two parts. One is the strain energy, which can be calculated by particle strain and stress. The other is heat, which can be calculated by the particle temperature change. For strain energy, I plan to output all the stress and strain of all the particles in each timestep, then I can calculate the increment of strain δε, then time σ, and the total volume and sum, which is the internal energy. For the heat, I plan to output all the temperature change, then times the total mass and specific heat capacity, which is the total heat generated. However, in some cases, I find that the sum of total strain energy calculated and total heat calculated does not equal to the total internal energy directly plotted in *MATSUM. Best,Rong