This thesis summarized the development in forming limit theory of shect metals.Based on the principle of stability, a suitable forming limit theory was found out, which can be used to build a new FLC.

• 本文总结了板料成形极限理论的发展状况，从稳定性的原始意义出发，找到了一较为合理的极限理论，并推导出一新的成形极限曲线。