薄壁球壳真空吸附装夹变形力学分析与控制

摘要

针对标准铝合金薄壁球壳零件的装夹变形问题,建立球壳变形的数学理论模型以及有限元仿真模型,实现了薄壁球壳真空吸附装夹状态的理论分析与仿真优化.明确了真空负压与装夹位置对球壳变形的影响;基于球壳与吸具之间的装夹位置关系,完成了吸具主要尺寸参数的优化设计.优化后吸具样件的测量结果表明,通过控制真空负压以及改变装夹接触位置,可以有效减小球壳的装夹变形,进而提高其加工的尺寸精度.%The thin-walled spherical shell workpiece is liable to deform during clamping before machining.A standard aluminum-alloy shell is taken for example.A mathematical model is established based on spherical deformation mechanism and finite element analysis.The theoretical analysis and simulation optimization are carried out for clamping design of semi-spherical shell with vacuum suction.The influences of suction strength and clamping location on deformation in the state of air pressure under average distributed load are analyzed.The result shows that the clamping deformation of shell can be minished effectively by controlling the suction strength and modifying the clamping location so that the machining size accuracy is improved.The main design parameter of vacuum fixture is optimized for the location relationship between shell and fixture.