Residual stress is the main factor that causes the deformation of connecting rod during its coupled machining process. Thus, it is essential to predict the residual stress and deformation of the connecting rod before its machining. As the traditional independent analysis method is no longer suit to the coupled machining process, a novel genetic-based method is processed. Firstly, the genetic mechanism of residual stress field and deformation field was established to realize the effective correlation of multiple machining process simulation models. Secondly, a milling process was established based on the birth and death element method, which converts complex milling processes into dynamic loading of milling forces and the death of elements of the FEM model. It realizes the coupling of initial residual stress (IRS) and machining induced residual stress (MIRS). Then, a multi-process simulation model of heat treatment, cutting off, and milling of connecting rod is established, which can reveal the evolution law of residual stress field under multi-process coupling of connecting rod, the coupling mechanism between IRS and MIRS, and the deformation response law of big hole cylinder of connecting rod. The proposed method will have great significance to the deformation control of connecting rod.

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Neglecting the influence of residual stress often leads to inaccurate predictions of camshaft life. Understanding residual stress evolution (RSE) under cyclic loading is the foundation for accurately predicting the fatigue life of camshafts. Camshafts are not subjected to uniform residual stress during manufacture, nor do they experience an evenly distributed load in service. Because studying the RSE of camshafts in service using only experiments is not practical, a combination of FEA (finite element analysis) and experimental verification is used. It is difficult for FEA to accurately predict the ratchet behavior of the stress and strain of a camshaft in service. To address this issue, our study proposes an experimentally-verified cyclic-plastic constitutive model that considers mixed hardening coupled damage (CDMH). RSE that is observed during camshaft manufacture and service is discussed. The results demonstrate that the CDMH model can accurately predict the RSE of camshaft in service, with an error less than 6.23%. We noticed that the compressive residual stress generated in the manufacturing process is enhanced and redistributed during service. The first cyclic load has the greatest contribution to the stress enhancement effect; the smaller the camshaft residual stress in the manufacturing process, the larger is the increased amplitude under the same load. The residual stress on the cam profile can be increased at least 6.02% by swing grinding, when compared with cutting grinding. This study provides a method for exploring RSE in camshafts under cyclic loading.