Energy Absorption in CFRP Tubes Under Dynamic Loading

Composite materials have excellent potential in automobile industry for energy absorption due to their superior characteristics in terms of energy absorption per unit mass compared to traditional metallic materials. Holes may represent an extreme case of impact damage that perforates the tube, e.g., stones from road surface impacting the tubes. Tubes with holes represent a more conservative performance characteristics since impact damage of the same size will have residual material which may carry some load. Tubes with holes can provide the lower limit of carbon fiber reinforced plastics tube performance under axial crushing relative to impact damaged tubes with perforation diameter close to the hole diameter. Dynamic response of tubes with and without holes have been experimentally characterized and then predicted using LSDYNA software. The performance of regular tubes and tubes with holes (15 mm dia) were similar and both tubes were able to absorb energy close to 53 kJ/kg. The size of the hole and its location chosen for this particular study did not appreciably affect the dynamic tube performance and both types of the tubes crushed in a progressive manner. The specific energy absorption values from experimental and computational results were found to be within 10% and average crushing load, P mean values were within 8% for both regular tubes and tubes with holes. Considering the complexity in failure modes, correlations between experimental and modeling results are considered very good for prediction of the dynamic response of the tubes.