Comparison of Kinetic energy and Strain energy
Comparison of Kinetic energy and Strain energy
(OP)
Through conducting a a dynamic implicit analysis using FE I am trying to make an assessment if inertial effects in my model can be ignored. If I were to compare the kinetic energy and strain energy under impact and check that there they are both negligible would this be a good enough indication that I can ignore inertial effects in my model?
Thanks
Thanks





RE: Comparison of Kinetic energy and Strain energy
I was under the impression that at the start of impact, there was kinetic energy, and at the end of the impact, it was all strain energy. I would think that kinetic energy would be irrelevant to your analysis. You should be able to read strain and deformation directly from your model, and compare this with your strain energy.
RE: Comparison of Kinetic energy and Strain energy
if your FEA shows negligible stresses in the structure, then you can easily say (depending on the validity of your analysis) that th eimpact has an insignificant affect on the structure.
RE: Comparison of Kinetic energy and Strain energy
Drawoh, wouldn't KE become important if it has affect on the impact as rb1957 is suggesting? And what would comparing strain to strain energy show?
rb1957, there is defintely impact in my problem and the stresses are not negligible.
Thanks again.
RE: Comparison of Kinetic energy and Strain energy
Your kinetic energy is converted into strain energy, hopefully, elastic.
If you know where the impact takes place, you should be able to apply a force there in your model, and read off the resulting deflection.
Strain Energy U = 1/2 Fδ
RE: Comparison of Kinetic energy and Strain energy
I noticed that strain energy formula is based on tension/compression htt
Not sure if it will apply to my ball in socket type problem?
RE: Comparison of Kinetic energy and Strain energy
1/2σijεij=1/2(σxxεxx+σyyεyy+σzzεzz+2σxyεxy+2σxzεxz+2σyzεyz)
Note: the factor of 2 on the shear strains goes away if you are using engineering shear strain γij=2εij