铝合金预拉伸厚板非均匀区应力场特征

Characteristics of non-uniform area in aluminum alloy prestretching thick plate

为了探求铝合金预拉伸厚板变形特点对应力场的影响,结合实验和有限元仿真,揭示了预拉伸工艺下厚板非均匀区应力演变规律.在不同尺寸厚板和不同工艺下,运用实验预拉伸机仿真模型,分析夹持区和过渡区应力场演变机理和规律.分析结果表明,非均匀区多样化的应力分布特点,不仅影响了厚板夹持稳定性,也对材料拉伸后的锯切率造成影响.拉伸时,夹持长度应不小于2倍试件厚度以保证拉伸稳定性.同时,过渡区范围与板厚度有关,其范围约为板厚的60%～70%,参考锯切长度为板厚3倍为宜.

In order to research the influence of deformation on stress field in an aluminum alloy prestretching thick plate,the stress evolvement of prestretching plate is presented by experiment and FEA simulation. For the plates with different thickness under different stretching conditions,mechanisms of stress-strain in clamping area and transition area are analyzed by FEM of prestretching machine. Results show that the variable and complicated distribution of stress in non-uniform area affects the stabilization of clamp plate and the determination of the area needed to be cut off. The stability of prestretching can be ensured by keeping the clamping distance 2 times more than the thickness. The transition area is related with thickness and it is 60-70 percent of the plate’s thickness,so the total length of non-uniform area needed to be cut off is approximate to three times of the plate thickness.