Impact behaviour of microwave-assisted compression moulded HDPE/kenaf and HDPE/MWCNT composites (MS)

Abstract

The present work deals with a novel manufacturing route, microwave-assisted compression moulding (MACM), for fabricating high-density polyethylene (HDPE) based composites. In the present work, 20 wt.% of reinforcement in the form of kenaf and multi-walled carbon nanotube (MWCNT) was used to fabricate HDPE/kenaf and HDPE/MWCNT polymer composites. The mechanical characterizations of the microwave processed composites were carried out in terms of the uniaxial tensile test at different strain rates, multi-step stress relaxation, flexural and impact test. The uniaxial tensile test revealed that the tensile modulus of four-layered HDPE/kenaf polymer composite was 35.2% higher than that of HDPE/MWCNT polymer composite. The HDPE/MWCNT polymer composite showed elastic modulus a minimum of 1.25 GPa and a maximum of 4.7 GPa when tested at different strain rates. The energy absorbed by the HDPE/kenaf polymer composite (1.055 J) was 81.12% higher than the HDPE/MWCNT polymer composite (0.582 J). Thereafter, the experimentally obtained properties have been utilized in crashworthiness testing of HDPE composites with respect to the aluminum alloy (Al5022) due to their comparable specific energy absorption. Finite element method (FEM) based ANSYS 16.0 package has been utilized to predict comparative crashworthiness strength of composites. Numerical results were obtained for full, offset and oblique frontal impact of the automobile body panel. Crashworthiness of the automotive body panel has been investigated on the basis of the deformation of the bumper, kinetic energy of the body panel and the reaction force of the target body. Although the directional deformation of the HDPE/kenaf and HDPE/MWCNT composites is higher than the aluminum alloy (Al5022), they have a considerably lower value of deceleration and reaction force during the impact period.