孔挤压过程中孔边应力应变演化规律的试验与模拟研究

该文采用挤压棒直接挤压的方法对LY12CZ铝合金进行孔挤压试验，测试了在不同过盈量、不同润滑条件下挤压时挤压力和孔边应变变化曲线。建立三维有限元模型，对挤压过程开展了数值模拟。结合试验和模拟结果，揭示了挤压过程中孔边应力应变的演化和分布规律；挤压力的变化特征以及摩擦系数和过盈量对挤压力的影响；孔的深度方向切向应力在挤压过程中的分布及孔边残余压应力的来源与演变。模拟值与试验测量值吻合良好，验证了有限元模拟的可靠性。

EXPERIMENTAL AND SIMULATION STUDY ON EVOLUTION OF STRESS AND STRAIN DURING THE HOLE EXPANSION

The hole expansion experiments were performed on LY12CZ aluminum alloy plate using a mandrel. The extrusion force and strain around the hole were measured under various interference values and friction coefficients. A 3D finite element model was built and the expansion process was simulated according to the experimental conditions. The results of experiments and simulations reveal the following regularities: 1) the evolution and distribution of stress and strain near the expanded hole; 2) the variation of the extrusion force under different interference values and friction coefficients; 3) the distribution of the tangential stress along the depth of the hole; 4) the origination and evolution of residual compressive stress around the hole. The simulation results are in good agreement with the experiments, which validate the reliability of the simulations.