Session: 03-07-01 Materials for Extreme Environment I

Paper Number: 107246

107246 - An Equivalent Modeling Scheme of Cellular Structure Under Extreme Loading Using Finite Element Method 

Bio-inspired cellular structures are being used for the armor design for human safety. During highly dynamic phenomena such as impact and shock/blast loading, these structures absorb energy by plastic deformation, hence minimizing injuries. Numerical approach employed for impact and ballistic simulations is well established for medium-range strain rates in range of 400 to 700 per second. However, under shock loading, the structure undergoes deformation with strain rates ranging from 10³ to 10⁴ per second as it involves rampant interaction of shock waves with structures. For numerical modelling of such phenomenon, ConWep and MM-ALE simulation techniques are used effectively. In ConWep, the shock loads applied on structures are empirically derived and extrapolated from the experiment which is suited for higher scaled distances. The interaction between eulerian and lagrangian mesh is defined using MM-ALE approach by using FSI (Fluid-structure interaction) coupling. Intuitively, these methodology are stable for a far field analysis but have shown inconsistency in predicting the behavior for close to contact blast scenarios. Current study investigates a deformable hybrid sandwich structure (such as cellular sandwich structures) subjected to close to contact blast scenario using non-cellular modelling techniqes. The cellular structure is defined using an equivalent material model by implementing continuum orthotropic properties, considering lagrangian mesh to ameliorate the computational time. Hydrocodes based finite element scheme employed in LS-Dyna for investigating specific energy absorption (SEA) and force transmission through the structure during the deformation intervals. Study aids in minimizing computational time and modelling complexities particularly in case of near field blast scenario. It is observed that the compression in sandwich structure differs in deformation pattern in near field scenarios when compared with far field scenarios.

Keywords: Bio-Inspired cellular structure, Near field, Shock-Wave Interaction, ConWep, MM-ALE

Presenting Author: Devendra K. Dubey Indian Institute of Technology Delhi

Presenting Author Biography: With masters degree in Mechanical Engineering and core strengths in Mechanical Design and Finite Element Analysis, I have more than 22 years of Research and Industry Experience.
Currently working on human safety in extreme loading condition at Indian Institute of Technology Delhi as a Senior Project Scientist. With a strong academics in Indian Institute of Technology Roorkee and experience in product development for defence I have a strong inclination towards a deeper understanding of high strain rate phenomena and material development for human safety.

Authors:

Praveen Verma Indian Institute of Technology Delhi
Rohit Sankrityayan Indian Institute of Technology Delhi
Anoop Chawla Indian Institute of Technology Delhi
Sudipto Mukherjee Indian Institute of Technology Delhi
Devendra K. Dubey Indian Institute of Technology Delhi