Crash Behavior of DP800–DP1000 Advanced High‐Strength Steel’s Dissimilar Resistance Spot Welded Joints Under Quasi‐static and High Strain Rates

Advanced high‐strength steels (AHSS) have been emphasized due to the pursuit of lightweight vehicles and improvements in crash safety because they offer high crashworthiness. Dual phase (DP) steels, for example, DP800 and DP1000, are used in high‐crash‐performance vehicle parts because they provide lower weight and good energy absorption during a collision. Considerable work has been conducted on high‐strain‐rate (HSR) properties of DP materials in their monolithic form; however, there has been limited research on the HSR properties of DP joints. In particular, little information is available on the HSR properties of DP welded joints (made using resistance spot welding (RSW)) and under dynamic loading conditions. This research has focused on determining the similarities and differences of DP800‐DP1000 welded joints produced using optimal RSW parameters; this will provide insight into the behavior of welded DP joints under strain rate testing. Test results indicate that DP welded joints have lower ultimate strength compared to their base metals; however, they have high levels of strain rate sensitivity; therefore, they absorb considerable energy during a crash. The results indicate the need to characterize AHSS welded assemblies under dynamic conditions to contribute to the development of safe lightweight vehicles.