Failure analysis of hybrid fiber reinforced polymer composite tubes subjected to quasi-static compressive load: an experimental study

This study focuses on the failure analysis of hybrid woven jute and glass fiber-reinforced structural composite tubes with circumferential circular holes under quasi-static testing. Process parameters were optimized to obtain outputs including maximum stress, energy absorption, and specific energy absorption by considering hole diameter, length of the tube, and number of holes drilled as input. Results portray that the crash behaviour of the composite tubes was dependent on the number of holes drilled on the circumference and the analysis of variance results revealed that the interaction between all the process parameters affected the output variables. Energy absorption and specific energy absorption were found to be maximum for the composite tubes of 70 mm length drilled with 4 holes each of diameter 12 mm. Optimal energy absorption of hybrid composite tubes was 87.11 J and the specific energy absorption was 1.527 J/g. A regression model was also developed to predict energy absorption and specific energy absorption. Confirmation experiments portrayed an appreciable correlation between the predicted and experimental values with a less than 5 % margin of error for energy absorption and a less than 2 % margin of error for specific energy absorption. The failure mechanism of the hybrid composite tubes was analyzed using photographs of the composite tubes from which the major failure mechanism was observed to be buckling failure through longitudinal crack propagation. Such short composite columns find their applications in roll-over protection in automobiles, as retrofits in construction applications and developing modular structural designs.