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毛坯残余应力的测量以及零件的加工变形分析是航空整体结构件数控加工工艺研究的难题。应用MSC.Marc软件对某型飞机主起支撑接头的7085铝合金锻件毛坯的淬火-压缩工艺进行了数值仿真,获得了毛坯残余应力分布趋势;应用X射线衍射法与钻孔法测量了毛坯表层残余应力分布,提出了基于系数修正法的毛坯残余应力分析方法,通过最小二乘法(LSM)拟合仿真值与试验值以获得应力修正系数,并对毛坯残余应力分布的仿真结果进行修正,获得了实际毛坯的残余应力分布;由此进行了主起支撑接头缩比零件加工变形仿真与验证试验。研究结果表明:7085铝合金块状毛坯残余应力数值仿真结果与测试结果的趋势吻合,为应力修正提供了物理基础;相对于未修正的应力分布,基于修正后的应力分布仿真获得的变形结果精度提高了50%;7085-T7452铝合金的毛坯残余应力是导致主起支撑接头加工变形的主要因素。
The measurement of the residual stress of the blank and the analysis of the deformation of the part are the problems in the research of numerical control machining technology for the whole structure of aviation. The application of MSC.Marc software was used to simulate the quenching-compression process of the 7085 aluminum alloy forging of a certain type of aircraft main support joint. The residual stress distribution trend of the blank was obtained. The surface roughness of the blank was measured by X-ray diffraction and drilling method Residual stress distribution, a method of residual stress analysis based on coefficient correction method is proposed. The simulation value and test value are fitted by LSM to get the stress correction coefficient, and the simulation result of the residual stress distribution is corrected. The residual stress distribution of the actual rough; from the main support joints shrinkage parts machining deformation simulation and verification tests. The results show that the simulation results of residual stress of 7085 aluminum alloy block are consistent with the trend of the test results, which provides the physical basis for stress correction. Compared with the unmodified stress distribution, the accuracy of the deformation result obtained from the modified stress distribution simulation Increased by 50%. The residual stress of 7085-T7452 aluminum alloy is the main factor leading to the deformation of the main support joint.