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运用有限元软件DEFRORM-3D对工件间推挤式等通道转角挤压(ECAP)技术进行了仿真模拟和试验研究(所用模具拐角为100°),重点分析了推挤变形过程及摩擦系数(μ)的影响、推挤接触区形貌与应变特征以及μ对最大挤压载荷、工件平均有效应变及加工单位体积工件产生单位有效应变所消耗的能量的影响。模拟结果表明,工件间推挤式ECAP加工与单根工件ECAP加工有很大不同。在该模拟条件下,μ≥0.7时,推挤式ECAP加工不能进行。工件推挤接触区形貌及接触面积在μ<0.5时,随着μ的增大,接触区形貌发生变化、接触面积增大,而当μ>0.5后,基本不发生变化。当μ≥0.5后,工件接触两端呈典型剪切变形特征,与单根工件ECAP加工有本质不同。工件接触区应变在μ=0.5时均匀性最佳,并与工件其他区域应变大小相差很小。最大挤压载荷随着μ增加而增大的幅度比传统ECAP更为强烈。工件的平均有效应变比单根工件ECAP加工的应变有所增加。工件间推挤式ECAP加工单位体积工件产生单位应变所消耗的能量随着μ的增大而增大。试验研究表明,当μ过大时推挤式ECAP加工不能进行,而当μ较低时可以实现推挤式ECAP加工,仿真模拟结果与试验结果吻合。
The finite element software DEFRORM-3D was used to simulate and test the squeezing isokinetic ECAP technology (the corner of the die was 100 °). The key points of the extrusion deformation process and the friction coefficient (μ ), The shape and strain characteristics of the pushing contact zone, and the influence of μ on the energy consumed by the maximum compressive load, the average effective strain of the workpiece and the effective strain of the unit of generating the workpiece per unit volume. The simulation results show that there is a great difference between ECAP processing of workpiece pushing and ECAP processing of single workpiece. Under this simulation condition, the push ECAP process can not be performed with μ ≧ 0.7. When μ <0.5, the shape of contact area and the contact area of workpiece push contact area change with the increase of μ, and the contact area increases. When μ> 0.5, it does not change basically. When μ≥0.5, the workpiece is exposed at both ends of a typical shear deformation characteristics, and a single workpiece ECAP processing is essentially different. The strain at the contact area of the workpiece is best at μ = 0.5 and the difference between the strain at the workpiece contact area and the other area of the workpiece is very small. The maximum compressive load increases with μ more than the traditional ECAP. The average effective strain of the workpiece is increased compared to the strain of a single workpiece ECAP process. Workpiece pushing ECAP processing Volume per unit volume of the workpiece The energy consumed by the strain increases with increasing μ. Experimental studies show that when μ is too large, ECAP processing can not be carried out, and when μ is lower, ECAP processing can be achieved. The simulation results are in good agreement with the experimental results.