Quasi-Static & Dynamic Spotweld Characterization for Automotive Crashworthiness Conditions 2015-26-0191

Robust and reliable FE-model spotweld characterization has been a challenge since spotweld technology was incorporated extensively into the automotive industry. The innovation required leads to constant enhancement of product performance; reduced time-tomarket, cost and weight. The need for quality requires robust development tools, consistency of design decisions, andrepeatability of the development process. Proper spotweld characterization has a clear impact on the above-mentioned needs and carmakers invest in efforts to increase the efficiency of the development process. Furthermore, the continuoususage of new steel grades increases the complexity of the topic. This paper presents an in-depth spotweld study that involves three different spotweld specimens: KSII; lap shear and peeling, for automotive steel grades and usual part thicknesses for each steel grade. The specimens are welded using automotive welding guns to ensure the representativeness of the samples following automotive standards during the manufacturing process. KSII specimen provides accurate information regarding the local spotweld properties. KSII specimen is tested considering three loading conditions: pure shear, pure tension, and 45 degree mixedmode. Lap shear and peeling specimens represent the typical joining geometry for spotwelded steel parts (e.g. flange welding). Crashworthiness is one of the development fields where the spotweld has a relevant role and the spotweld FEmodel should capture the comprehensive spotweld behaviour.

This is elasto-plastic, damage and failure behaviour in both quasi-static and dynamic conditions. The study analyses quasi-static behaviour for all the aforementioned specimens together with dynamic behaviour for both peeling and lap shear specimens.