Crashworthiness of Aluminum Extrusion Under Simulated Service Life Heat Exposure

An investigation of the service life aging and heat exposure effects on extruded aluminum alloy properties and structural crashworthiness has been conducted. This research, part of a broader program, consists of investigating five aluminum alloy extrusions each of which is subjected to two heat treatments. The aluminum extrusion investigated are 6063T6, 6061T6, 6260T6, 6014T6, and 7129T6. The two heat treatments are 177°C for 30 minutes and 200°C for 24 hours. The 200°C/24 hours treatment represents an upper limit thermal exposure i.e. components adjacent to exhaust pipes and manifolds. The 200°C heat treatment was applied in addition to the 177°C for 30 minutes. All specimens were subjected to the reference 177°C for 30 minutes treatment. These ten crash members were subjected to dynamic axial crashing at a target speed of 40 kph (25 mph). Force-time data was collected and responses were plotted for all tests. Force-displacement responses were then integrated for the crash energy management and mean axial crash load for each of the aluminum extruded crash members. Bar charts were then generated to describe the crash loads and energy management behaviors of the various aluminum alloys and associated heat treatments. Service life simulated heat exposure was found to effect the mean crash load and crash energy management of the aluminum structural crash members. The heat exposure effects on the crashworthiness of the extruded aluminum members ranged from a reduction of 10% to over 20% in the mean crash load and crash energy management with highest variation observed with the 6260T6 aluminum extrusion.