板料成形极限理论与实验研究进展

成形极限是板材成形领域中重要的性能指标和工艺参数。文章在阐述成形极限在板料成形中的意义的基础上,综述并分析了成形极限在理论和实验方面的研究进展。成形极限图受应变路径的影响,给工业生产应用带来极大不便。以极限应力构成的成形极限应力图不受应变路径的影响,作为复杂加载路径的成形极限判据更加方便和实用。FLSD研究与FLD相结合,成为精确地确定破裂判别准则的主要途径之一,是近来研究的热点。十字形双向拉伸是实现复杂加载路径有效实用的试验方法。最后对成形极限应力图和十字形双向拉伸试验需要解决的关键问题作了阐述。

Theoretical and experimental investigation progress on the forming limit of sheet metal forming

Forming limit is the most important formability index and process parameter in sheet metal forming. On the basis of the expatiation on the effects of forming limit to the research and application of sheet metal forming, this paper overviews and analyses the theoretical and experimental investigation progress on the forming limit. FLD is remarkabaly affected by the strain paths, which brings the inconvenience to industry. And the forming limit stress diagram which established with limit stress is independent on the strain paths and it is more convenient and practical to use as the criterion of forming limit under complex strain paths. Therefore, the research of the FLSD combined with FLD becomes the hotspot and one of main approaehs to establish the limit criterion accurately. The cruciform biaxial tensile test is an effective and practical method to realize the process of complex strain paths. Finally, the pivotal question is expounded for the FLSD and the cruciform biaxial tensile test.