Rigid body introduces SPH element and negative mass

- September 21, 2025 at 5:16 pm
  
  Mohammad Arif Shahriar
  Subscriber
  
  Hi. I am trying to run a simulation of low velocity impact on composite in LSDYNA, ANSYS Workbench. A composite body (flexible) modeled in ACP and a impactor body (rigid) modeled in mechanical model in present here. I am getting SPH errors.
  
  If I convert the impactor to a flexible body with high stiffness the simulation runs well though I will have to validate the results. But changing to rigid body is causing this SPH errors. I am not familiar with this error and cant figure out what's causing them.
  
  I can consider SPH but even then there is a negative mass error. All the pictures are attached here.
  Any help will be much appreciated. Thanks.
- September 22, 2025 at 7:14 am
  
  Neetu Jha
  Ansys Employee
  
  Hi, *MAT_RIGID is not supported by SPH thats why this error comes!