铝挤压机压余剪切过程有限元模拟

摘要

Taking the 7075 extruded aluminum alloy as the example ,the finite element simulation on discard shearing process was carried out by using Forge software and fracture criterion of Crockroft & Latham ,and the influence of shearing velocity and discard thickness on max shearing force was studied .The results show that the shape of shearing force curves is arched ,and the max shearing force is not found to be influenced by shearing velocity within a certain range ,but it increases with the increasing of discard thickness ,as for an increase of 10 mm of discard thickness ,the increase of max shearing force amplitude is about 15% .In order to estimate max shearing force ,through comparing the simulation results with practical formulas ,it is determined that if discard thickness is less ,then the lower value of allowable shearing stress should be adopted ,on the contrary ,it is recommended that the allowable shearing stress is replaced by allowable tensile stress .%铝挤压机压余剪切过程受力形式复杂。以某规格7075铝合金挤压为例，基于Forge软件和Crockroft& Latham断裂准则对压余剪切过程进行了有限元模拟，研究了剪切速度和压余厚度对最大剪切力的影响。结果表明：剪切力曲线呈拱形；剪切速度在一定范围内变化时，最大剪切力几乎不受其影响；随压余厚度增加，最大剪切力呈线性增加，压余厚度每增加10 mm ，最大剪切力约增幅15％。为估算最大剪切力，将模拟结果与经验公式计算结果进行对比，确定若压余厚度较小，许用剪切应力应取低值；而压余厚度较大时，建议许用剪切应力用许用拉应力代之。