Considerations for Numerical Modeling of Dynamic Behavior of Soft Materials
Numerical simulations of split-Hopkinson pressure bar experiments on soft, nearly-incompressible specimens have been used to validate an “inertial correction” theory for specimens with a bulk-to- shear modulus ratio (κ/μ) on the order of 104. Applying the “inertial correction” theory to specimens with κ/μ on the order of 106, we find that changes in stress computations in the simulation upon refining the mesh may be on the same order as the axial deviatoric stress necessary to separate a rate-dependent effect from the inertial material response. Simulations executed with a series of refined meshes were used to calculate nominal stress estimates at the bar-specimen interfaces and determine the most effective meshing and stress estimation techniques. Our results suggest that average cross-sectional average stresses computed from specimen mesh data at the bar-specimen interfaces are less likely to have mesh dependencies due to contact interactions in simulations. Additionally, it is suggested that radial element lengths in the bar mesh should be scaled to approximately 11% of the specimen length, and the element lengths in the specimen mesh scaled to less than 8% of the specimen length; this serves to increase the resolution of stress computations at an element centroid.
KeywordsAxial Stress Specimen Radius Mesh Case Ballistic Gelatin Axial Deviatoric Stress
- 1.Scheidler MJ, Fitzpatrick J, Kraft R (2011) Optimal pulse shapes for SHPB tests on soft materials. In: Proust T (ed) Dynamic behavior of materials. Conference proceedings of the society for experimental mechanics series 99, vol 1. The Society for Experimental Mechanics Inc/Springer, New York, pp 259–268. doi: 10.1007/978-1-4614-0216-9_37Google Scholar
- 3.Gray GT III (2000) Classic Split-Hopkinson pressure bar testing. In Kuhn H, Medlin D (eds) Mechanical testing and evaluation. ASM handbook, vol 8. American Society for Metals, Materials Park, pp 462–476Google Scholar
- 5.Ramesh KT (2009) High strain rate and impact experiments. In: Sharpe WN (ed) Springer handbook of experimental solid mechanics, chap. 33. Springer, New York, pp 1–30Google Scholar
- 8.Moy P, Weerasooriya T, Juliano TF, VanLandingham MR, Chen W (2006) Dynamic response of an alternative tissue simulant, physically associating gels (PAG). In: Proceedings of the 2006 SEM annual conference, Saint LouisGoogle Scholar