Ls-dyna energy ratio

- March 26, 2024 at 10:21 pm
  
  Fady Elshazly
  Subscriber
  
  Hello,
  
  I have been working on a model in Ls-Dyna and the energy ratio doesnt start at 1 as shown in the attached screenshot. The analysis has dynamic relaxation and then a transient analysis. when i removed the dynamic relaxation to check, the energy ratio was always 1. is this causing any problem to not start from 1 when i consider the dynamic relaxation and how to solve that.
  
  Thanks
- March 27, 2024 at 4:57 pm
  
  Jim Day
  Ansys Employee
  
  In your example, I'm assuming the loads applied in the dynamic relaxation phase are being held constant in the transient phase and there is no additional loading. The energy ratio plot may be an inconsequential energy bookkeeping error. Unfortunately, there is not a way to output glstat data during the dynamic relaxation phase, so we really don't know the energy ratio at the end of dynamic relaxation. Between time=0 and t=10 of the transient phase, are you seeing a state of equilibrium, e.g., no variation of element stresses or nodal displacements? If not, that indicates that a state of equilibrium was not obtained during the dynamic relaxation phase and some adjustments to *CONTROL_DYNAMIC_RELAXATION are needed. You can postprocess relax and d3drlf to get a clearer sense of the response during the dynamic relaxation phase.