36. computational shock dynamics and its application to explosive welding

Department: Structural Engineering
Research Institute Affiliation: Center for Extreme Events Research
Faculty Advisor(s): Jiun-Shyan Chen

Primary Student
Name: Tsunghui Huang
Email: tsh011@ucsd.edu
Phone: 858-534-7034
Grad Year: 2021

Abstract
The explosive welding (EXW) process entails shock waves, large plastic deformation, and fragmentation around the collision point, troubling the traditional mesh-based methods for reliable solution. In this work, a computational framework based on the reproducing kernel particle method (RKPM) is developed for shock modeling. RKPM is considered herein due to its versatility in adaptive refinement and in adjusting smoothness independently to the order of completeness in the approximation. The following issues are properly addressed in modeling shock wave propagation in hydrodynamical systems: (1) correct representation of essential shock physics, (2) stabilization of Gibbs phenomenon at discontinuity, and (3) capturing shock front with minimal smearing of moving discontinuity. A stabilized conforming nodal integration (SCNI) and non-conforming nodal integration (SNNI) are constructed with locally enriched Riemann flux, such that the essential shock physics, Rankine-Hugoniot jump condition and Lax entropy condition, are satisfied. The oscillation control is provided through the smoothed flux divergence in the SNNI and SCNI framework. Semi-Lagrangian reproducing kernel particle method (SL-RKPM) under such framework is introduced for the modeling of EXW. The effects of high strain-rate and high temperature on plasticity and damage in the metals are taken into consideration in the material law. The kernel stability in SL-RKPM to accurately capture excessive plastic flow and metal jetting is ensured by introducing a strain rate dependent kernel support update. The jet formation, smooth to wavy interface morphologies transition, and the welding condition along the metal interface are compared to several experimental results to validate the effectiveness of the proposed methods for EXW modeling.

Industry Application Area(s)
Aerospace, Defense, Security | Civil/Structural Engineering | Materials

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