Description of Invention
This invention is about the design of material layup in composite tubes to maximize crashworthiness. Past and present inventions focus on different structural enhancements, and material hybridization is often in the tube radial direction. This invention, deploying graded materials in the tube axial direction, reveals that crashworthiness can be significantly enhanced by arranging materials with higher stiffness or mechanical impedance at the impacted end. Specific energy absorption in a dynamic impact can be increased by at least 18% when compared to conventional hybridization. The effect is equivalent to having twice the amount of carbon content in the tube.