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金属薄板在深冲成形过程中,常见的失效形式为拉应力引起的开裂以及压应力引起的起皱。后者可以通过模具或工艺参数的调整予以防止和控制。换句话说,起皱并不是由于材料本身造成的。因此,薄板在深冲成形中是否会发生开裂,才是大家更为关心的问题。造成开裂的主要原因有二类。一是在局部大变形区内的成形过程不是依靠周围料的补充,而是主要依靠本身的减薄来实现,当变形量较大时便导致开裂。另一类是在材料变形时,某处发生拉伸失稳,从而过早地开始颈缩以致开裂。
Metal sheet in the deep drawing process, the common failure forms of tensile stress caused by cracking and compressive stress caused by wrinkling. The latter can be prevented and controlled by adjusting the mold or process parameters. In other words, wrinkling is not caused by the material itself. Therefore, the thin plate deep drawing in the case of cracking occurs, it is everyone more concerned about the issue. There are two main causes of cracking. First, the forming process in the large deformation zone does not depend on the supplement of the surrounding materials. Instead, it mainly relies on its own thinning, which leads to cracking when the deformation is large. The other is when the material is deformed, unstressed somewhere, causing the neck to start cracking prematurely.