Crashworthy characteristics of axial quasi-statically compressed Bombyx mori composite cylindrical tubes: Experimental

Abstract

The study investigated the energy absorption response and load carrying capability of Bombyx mori (B. mori) natural silk fibre/epoxy composite cylindrical tubes subjected to an axial quasi-static crushing test. The reinforced cylindrical composite tubes were prepared using hand lay-up technique. Varied numbers of B. mori layers, 12, 24 and 30 were used to fabricate the tubes; their corresponding diameters were 33.3, 62.3 and 80.6 respectively. The crashworthiness of the cylindrical tube was analyzed by measuring the specific energy absorption, peak load and total energy absorption as a function of tube diameter/number of layers under a quasi-static axial compression load. Failure mechanisms of the tubes were analyzed using scan electron microscopy (SEM) and high resolution photographs obtained during test. Generally, the result showed increase in crashworthiness behaviour as the numbers of B. mori layers increased. The 12 layer tube (33.3 mm diameter) showed a progressive crushing failure starting from the upper half; the 24 layer tube (62.3 mm diameter) depict a mid-length crack failure, while the 30 layer tube (80.6 mm diameter) showed a progressive crushing failure from the lower side of the tube. The SEM micrographs of suggest that failure mechanism includes: matrix crack, fiber delamination, fiber pull out, tear and fibre breakage.