Search Results

Hat-sections, single and double, made of steel are frequently encountered in automotive body structural components. These components play a significant role in terms of impact energy absorption during vehicle crashes thereby protecting occupants of vehicles from severe injury. However, with the need for higher fuel economy and for compliance to stringent emission norms, auto manufacturers are looking for means to continually reduce vehicle body weight either by employing lighter materials like aluminum and fiber-reinforced plastics, or by using higher strength steel with reduced gages, or by combinations of these approaches. Unlike steel hat-sections which have been extensively reported in published literature, the axial crushing behavior of hat-sections made of fiber-reinforced composites may not have been adequately probed.

Space frame type vehicle construction with extruded aluminum members holds promise in terms of desirable vibration-resistant and crashworthiness characteristics. Efficient design of such vehicles for superior frontal crash performance can be accomplished by judicious use of validated finite element and lumped parameter modeling and analysis. However, design iterations can be reduced considerably by employing energy-absorption targets for key members such as front rails in arriving at the initial design concept. For the NCAP (New Car Assessment Program) test procedure, a constraint is laid in terms of achieving a desirable level of vehicle peak deceleration for occupant safety. Using the information obtained through analysis, a numerical target can be set for energy to be absorbed by front rails. For this energy target, a new relationship is then derived which can be utilized for preliminary design of rail cross-section and material strength.