US Patent 8382199 Energy absorbing side rail for a vehicle

A side rail for vehicles has a tensile strength in excess of 1400 MPa and has one end (16) projecting from the safety cage of the vehicle and adapted to carry a bumper. The end projecting from the safety cage has lower strength with a yield point of less than 1000 MPa over a length of at least 0.4 m. It has an outer portion with a length of at least 0.2 m and a tensile strength below 800 MPa and an inner portion with a higher tensile strength than the outer portion.