Investigation on the scale effects of initial bulk and machining induced residual stresses of thin walled milled monolithic aluminum workpieces on part distortions: experiments and finite element prediction model
Investigation on the scale effects of initial bulk and machining induced residual stresses of thin walled milled monolithic aluminum workpieces on part distortions: experiments and finite element prediction model
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DOI：
10.1016/j.procir.2021.09.058
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发表时间：
2021
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影响因子：
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通讯作者：
D. Weber;B. Kirsch;C. R. Chighizola;J. E. Jonsson;C. D'Elia;B. Linke;M. R. Hill;J. Aurich
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文献类型：
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作者：
D. Weber;B. Kirsch;C. R. Chighizola;J. E. Jonsson;C. D'Elia;B. Linke;M. R. Hill;J. Aurich
薄壁整体铣削铝工件因其良好的性能（例如较高的整体强度重量比）而常用于航空航天工业。加工后这些零件会发生变形。残余应力 (RS) 是这些变形的主要驱动因素。两种类型的 RS，即初始体积残余应力 (IBRS) 和加工引起的残余应力 (MIRS)，都会导致零件变形。在这项研究中，针对不同的壁厚、不同的 IBRS 条件和不同的 MIRS，评估了每种 RS 类型的尺度效应及其对铣削薄壁铝工件变形的综合影响。在此背景下，开发了有限元模型 (FEM) 来预测由于测量的 RS 引起的失真。提出了将两种类型的 RS 作为输入的 3D 线性弹性模型。仿真结果通过实验进行了验证。结果发现，两种 RS 类型都会导致零件失真。对于包含高 IBRS 的部件，这些 IBRS 会主导失真。对于含有低 IBRS 的应力消除零件，MIRS 主导变形。研究表明，加工引起的剪切 RS 对于变形至关重要。开发的 FEM 模型能够预测两种 RS 类型造成的失真。
Thin walled monolithic milled aluminum workpieces are commonly used in the aerospace industry, because of their good properties such as a high overall strength-to-weight ratio. After machining those parts distortions occur. Residual stresses (RS) are the main driver for those distortions. Two types of RS, the initial bulk residual stresses (IBRS) and the machining induced residual stresses (MIRS), contribute to the part distortion. In this study, the scale effects of each RS type and their combined effects on the distortion of milled thin walled aluminum workpieces are evaluated for different wall thicknesses, different IBRS conditions and different MIRS. In this context a finite element model (FEM) is developed to predict the distortion due to the measured RS. A 3D linear elastic model, considering both types of RS as input is presented. The simulation outcome is validated by experiments.It was found that both RS types contribute to part distortion. For parts containing high IBRS, those IBRS dominate the distortion. For stress relieved parts, containing low IBRS, the MIRS dominate the distortion. The investigations showed that the shear RS induced by machining are crucial for the distortion. The developed FEM model is able to predict the distortion due to both RS types.