薄板微冲压成形失稳分析与实验研究

针对薄板微冲压成形过程中产生的尺度效应现象，以塑性应变梯度理论的本构方程为基础，推导出基于应变梯度的集中性失稳准则，并对薄板微冲压成形过程进行分析，得到冲压成形深度与极限应变值的关系，以及材料发生极限应变时的极限成形深度.同时，设计了相应的微冲压成形实验.结果表明，材料在微冲压成形过程中的成形极限小于宏观成形过程的成形极限，新的失稳准则能够更为准确地预测薄板微冲压成形过程中的成形极限.

Instability Analysis and Experimental Study of Micro Stamping Process with Thin Sheet

Focusing on the size effect which appears during the process of micro scale stamping, a new fracture criterion was derived from the constitutive equation based on strain gradient. Then, the stamping process of thin sheet was studied to obtain the relationship between the forming depth and strain. As a result, the limit of forming depth could be predicted accurately. Finally, a series of micro stamping experiments were conducted, which shows that the new fracture criterion is available.