Formability, defects and strengthening effect of steel/CFRP structures fabricated by using the differential temperature forming process

摘要

Steel/CFRP materials consisting of steel sheets and CFRP prepregs are attracting more and more attention as the development of new energy vehicles requiring strongly weight reduction as well as the cost reduction of available constituent materials. This study is the first to propose the differential temperature forming process to fabricate steel/CFRP structures. The successful fabrication for steel/CFRP U-shape and box-shape structures demonstrates the excellent forming capability of the used forming process for steel/CFRP materials. Moreover, the steel/CFRP U-shape structures are found to possess a higher forming precision than their pure steel counterparts due to the smaller springback. For the steel/CFRP box-shape structures, the typical forming defects and their formation mechanisms are analyzed in detail. Finally, the steel/CFRP U-shape and box-shape structures are validated to have much higher load-carrying capability and better energy absorption property than their single material counterparts by crushing tests. Furthermore, the steel/CFRP U-shape structure can obtain more obvious strengthening effect compared to the steel/CFRP box-shape structure. So, they are particularly suitable for serving as the load-carrying channel parts widely used in automobile industry.