Session: FSI-03-01 Structures Under Extreme Loading Conditions-1

Paper Number: 154207

154207 - Coupled Fluid-Structural Analysis of Explosion Containment Using Crushable Sandwich Structures. 

Abstract: 

Explosions can generate high-velocity, high-pressure shock waves capable of inflicting severe damage to the nearby civilian entities. One approach to mitigate this damage is to confine the explosion in containers certified to withstand the extreme pressure loads. Containment structures can be generally classified as multi-use or single-use. Multi-use containers, commonly constructed with thick steel walls, can endure multiple explosions with small elastic deformation. However, these structures tend to be heavy, expensive, and difficult to transport, making them less accessible for local public safety agencies. In contrast the single-use structures are compact and lightweight, which offer a promising solution for such applications. These structures are designed to dissipate applied blast energy through large, permanent deformation without fracturing. Recent advancements in material technology, particularly the development of sandwich composites with soft cores and stiff face sheets, have made lightweight containment structures a feasible solution. Cores made from materials like foams, which exhibit extended plastic plateaus followed by non-linear densification, significantly improve the shock absorption efficiency of these composites. The applied blast energy is effectively dissipated through plastic work and substantial core crushing.
    Simulating the response of sandwich containment structures is an arduous task due to the different length and time scales associated with detonation, shock propagation, and the non-linear structural response. In this study, we utilize a recently proposed three-stage simulation procedure that resolves each physical process on their respective time scales. Unlike external explosions that take place in open environments, internal explosions involve complex wave propagation, reflections, and interactions within the confined space. During this process, the structural dynamics and the fluid flow mutually influence each other. This complexity is addressed by coupling the finite volume fluid dynamics solver and the finite element structural dynamics solver through a partitioned procedure. The open-source solvers M2C and Aero-S are used to simulate the fluid dynamics and the structural dynamics, respectively. An embedded boundary method is utilized, which enables the fluid-structure interface to be tracked within a fixed, non-body-fitted fluid mesh. The method accommodates large structural deformations without the need for frequent fluid re-meshing. The fluid-fluid interface is tracked implicitly using a level-set method. We compute the mass, momentum, and energy fluxes across the material interfaces using the recently developed Finite Volume Exact Riemann (FIVER) solver, which locally constructs and solves a bi-material Riemann problem. One of the salient features of FIVER is that it explicitly accounts for the discontinuity of Equation of State (EOS) across the material boundary. 
    A case study will be presented on a fully confined containment structure made of sandwich composite materials, featuring a soft metallic foam core and aluminum face sheets. The containment structure will be subjected to The containment structure will be subjected to an internal explosion of 250 g TNT. The main features of the simulation results will be presented, including the propagation and interaction of shock waves inside the chamber, non-linear foam hardening and large plastic structural deformation. 

Presenting Author: Aditya Narkhede Virginia Polytechnic Institute and State University

Presenting Author Biography: Aditya Narkhede is a Ph.D. candidate in the Department of Aerospace and Ocean Engineering at Virginia Tech. Originally from India, he holds a Bachelor's degree in Civil Engineering and a Master's degree in Aerospace Engineering. His research centers on fluid-structure interactions and structural optimization, with a particular focus on structures subjected to detonation-induced shock loads.

Authors:

Aditya Narkhede Virginia Polytechnic Institute and State University
Shafquat Islam Virginia Polytechnic Institute and State University
Kevin Wang Virginia Polytechnic Institute and State University