针对铝合金厚板内部残余应力检测难、预测难、控制更难的问题,通过三因素三水平正交试验,运用裂纹柔度法检测了7075铝合金预拉伸板的内部残余应力,总结了其分布规律,根据厚板内部的应力分布特点,构造了应力分布线型函数;运用非线性回归技术,建立了关键点应力值与淬火板表面应力的关系,构建了预拉伸板残余应力场评估模型.结合测试得到的淬火板表面应力和回归得到的关键点应力值,重构预拉伸板残余应力场.对某厂生产的预拉伸板进行的残余应力评估表明,该模型具有较强的工程实用性.

In order to easily measure,predict and further control the internal residual stress of thick aluminum alloy plates,first,the internal residual stress of thick 7075 aluminum alloy plate was measured by crack compliance method based on 3-factor 3-level orthogonal experiments.Next,the distribution law of the residual stress was summarized,and a shape function describing the stress distribution was established according to the distribution characteristics of the stress.Then,the relationship between the stress at key points and the residual stress of the plate surface was revealed via the nonlinear regression,and a model to evaluate the residual stress field of the pre-stretched plate was put forward.The model was applied to the evaluation of residual stress of a certain Al alloy plate,with its feasibility being verified at last.