Date of Award

4-2016

Document Type

Thesis - Open Access

Degree Name

Master of Science in Aerospace Engineering

Department

Mechanical Engineering

Committee Chair

Dr. David J. Sypeck

First Committee Member

Dr. Dae Won Kim

Second Committee Member

Dr. Feng Zhu

Abstract

Sandwich structures with composite facing skins have seen applications in variety of sectors including aerospace and automobile, owing to their high specific mechanical properties. However, there is a need to develop better damage tolerant sandwich structures since conventional composite facing skins exhibit low impact resistance in the transverse direction. Here, composite skin sandwich structures with three different impact resistant core materials were fabricated and tested both experimentally and numerically. Neat CFRP and 2024-T3 aluminum alloy sheets were also investigated. Cores utilizing impact resistant D3O® were found to have very favorable weight specific energy absorbing properties at higher impact velocities as compared to those made from Nomex® or Sorbothane® cores. Nonlinear finite element analysis was also performed using Hypermesh/LS-DYNA for 2024-T3 aluminum alloy sheet, neat CFRP and sandwich with Nomex® core with CFRP faceskins. Numerical vs. Experimental impact results were compared and comments regarding impact behavior of different candidate materials were made. CAI tests were performed for CFRP sandwich structures. Sandwiches with cores made out of D3O® and Sorbothane® showed more ductility when compared with Nomex® core sandwich composite.

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