Session: 01-06-02: Impact, Fatigue, Damage and Fracture of Composite Structures

Paper Number: 108370

108370 - High Velocity Impact Damage Assessment of Sandwich Panels With Uniform and Functionally Graded Tpms, Auxetic Re-Entrant Cellular Cores 

The architected cellular structures have gained a lot of attention in recent years due to their lightweight, superior and controllable properties. Such lattice structures can be potential candidates for high specific energy absorption applications due to the increase in structural performance. This increase in mechanical properties can be attributed to the gradual and localised changes occurring in the cellular cores. In this study, two TPMS sheet-based structures (Diamond, Gyroid), one re-entrant auxetic structure, and one honeycomb structure were designed, fabricated, and tested under both quasi-static and dynamic loading conditions. Fused Filament Fabrication (FFF) method is used for fabrication of the complex specimens. High velocity impact tests have been carried out with a projectile of 9.8mm diameter hemispherical shaped mild steel projectile for determining the ballistic limit, energy absorption, and residual velocity. Quasi-static tests are carried out at a strain rate of 0.005s^-1 and the ballistic tests are carried out at velocities of 165 m/s, 195 m/s, and 220 m/s for the investigation of damage mechanisms. The changes in plateau stress, specific energy absorption, and damage pattern are compared among the auxetic, TPMS, and honeycomb sandwich panels along both loading rates. Furthermore, the effect of changing the cellular structures with variation in density and cell size has also been studied The study shows that the sandwich panels with cellular cores show an enhanced performance under dynamic loading. It is also observed that the SEA of the TPMS cores is higher than the strut-based auxetic re-entrant cores. There is a significant improvement in impact properties for the graded cellular structures where smaller deformation of the cores is visible along with a high stiffness ratio of core/plate.

Keywords: Sandwich panels; Impact; Triply periodic minimal surfaces; Auxetic re-entrant; Blast loading; 3D printing

Presenting Author: Itkankhya Mahapatra Indian Institute of Technology Madras

Presenting Author Biography: I am currently a Ph.D. candidate at Department of Aerospace Engineering, IIT Madras advised by Prof. Velmurugan and Prof. Jayaganthan. The focus of my research is on investigating the geometrical features, fabrication process, and mechanical properties of additively manufactured lattices and composites using different materials and loading conditions. My research also focuses on the engineering application of additive manufacturing in different engineering disciplines. I received my M.Tech. from National Institute of Technology, Rourkela, India, under Professor Ritwik Sarkar and my B.Tech. in Mechanical Engineering from Institute of Technical Education & Research, SOA University in Bhubaneswar, India.

Authors:

Itkankhya Mahapatra Indian Institute of Technology Madras
Velmurugan Ramachandran Indian Institute of Technology Madras
Jayaganthan Rengaswamy Indian Institute of Technology Madras