Fabrication and Structural Equivalency Analysis of CFRP Nomex Core Sandwiched Panels for FSAE Race Car

Muhammad Yaqoob

Abstract


Composites sandwich structures have been increasingly used in applications where high strength and stiffness to weight ratio is required to reduce weight for energy saving and optimum performance purposes. Aim of this project was to manufacture a sandwich panel with carbon fibre reinforced plastic (CFRP) skins and a Nomex honeycomb core using the wet layup method and to test it against the requirements specified in FSAE Rules for side impact and front bulkhead monocoque structures of car chassis. Investigations were made into different skin thicknesses to choose best skin thickness for the sandwich panel to improve its weight and characteristics. Tests conducted on sandwich panels were shear perimeter test and three-point bending test. From previous work and testing, shear perimeter test was found as a limiting case out of the two tests. Results showed that selected material passed both tests and was far above the baseline material and Aluminium honeycomb sandwich panel which were tested last year. From results it was established that shear perimeter strength of sandwich panel depends upon skin thickness whereas, energy absorbed by the panel during testing process is dependent upon the thickness of the core. Failure modes of CFRP-Nomex sandwich panels were quite different than Aluminium sandwich panels. In shear perimeter test, CFRP layers in each skin failed individually which was evident from kinks in the graphs. Results also indicated that CFRP material is weaker in compression than in tension.

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