43. RECENT ADVANCES IN MODELING EXTREME EVENTS AND APPLICATION TO HOMELAND SECURITY
Name: Guohua Zhou
Grad Year: 2016
Predicting failure due to extreme loads on structures such as impact and blast is of great importance for homeland security. Effective numerical methods facilitate the advancement of protection against extreme conditions by enabling damage estimation and evaluation of threat mitigation strategies. Key physics and phenomena to be captured in this class of problems include high-rate loading, complex crack propagation and material damage, fragmentation, shock propagation, and multi-body contact. A semi-Lagrangian meshfree Reproducing Kernel Particle Method (RKPM) is proposed for modeling these extreme events, in order the overcome the difficulty in traditional finite element methods which are unable to handle the large material distortion and material separation involved in these processes. A damage model is proposed where the damage evolution in the continuum is linked to the micro-cracking in the concrete microstructures. A new accelerated numerical technique is introduced to provide stability of the solution with very low computational cost, reducing the CPU time by up to twenty times over previous methods. An algorithm is developed for capturing shock physics and eliminating pressure oscillations that cause non-physical damage and premature failure. A quasi-linear formulation is also introduced that achieves accuracy previously unattainable when modeling this class of problems. The proposed method is extensively verified against experimental data, and several examples are given to demonstrate the effectiveness of this framework for modeling homeland security problems.
Industry Application Area(s)
Aerospace, Defense, Security | Civil/Structural Engineering | Materials