基于残余应力释放的航空结构件加工变形模型与结构优化方法

MACHINING DEFORMATION MODEL AND STRUCTURAL OPTIMIZATION OF AERONAUTICAL MONOLITHIC COMPONENTS BASED ON RELAXATION OF INITIAL RESIDUAL STRESS

  • 摘要: 在毛坯成形过程中,材料力学性能的非均匀性导致铝合金厚板内产生残余应力,以致在后续切削加工过程中,随着材料的去除,残余应力的释放使得整体结构件发生变形,严重影响着整体结构件的尺寸稳定性。因此,定量化研究切削过程中残余应力释放的加工变形分析与预测是进行加工质量控制的核心环节,对于实现加工过程的高效化和精密化至关重要。通过铝厚板的材料去除转化为残余应力的释放,利用静力平衡条件将作用于整体结构件的残余应力等效为外力后,综合考虑铝厚板横向方向和轧制方向的残余应力,依据弯曲变形理论创新性地建立铝厚板内初始残余应力释放模型。残余应力释放模型不仅能够准确地计算整体结构件的加工变形,而且还能够方便地优化工艺参数完成加工变形的有效控制。根据模型计算值与有限元仿真值、实验测量值的相互比较,分析结果表明:无论是幅值还是变形曲线,计算值都与仿真值具有高度一致性,而与测量值相比,尽管在变形曲线上具有很好的吻合性,但由于残余应力的测量误差使得两者在幅值上亦存在一定误差。

     

    Abstract: In the process of blank forming, the non-homogeneity of mechanical properties of material leads to the residual stress in a aluminum alloy thick plate. During the following cutting process, along with the removal of material, the release of residual stress makes the aeronautical monolithic component deformed, which seriously affects the size stability of an aeronautical monolithic component. Therefore, the quantitative study on the analysis and prediction of deformation caused by the residual stress release during the cutting process is the core link of controlling the processing quality, and it is very important for the realization of machining process with high efficiency and precise. Through equaling the material removal of the aluminum thick plate to the residual stress release, the residual stress of the aeronautical monolithic component is converted to an external force on the basis of static equilibrium conditions. Then considering the residual stress in both the transverse and rolling direction of the plate, the deformation analysis model is established by using bending deformation theory. The comparison between calculated results of a model and the finite element simulated results and the experimental measurement data shows that:both the amplitude and deformation curve and the calculated results are highly consistent with the simulated results; when compared with experimental measurement data there is a deviation in the amplitude due to the measurement error, though the deformation curve of calculated results has a good agreement with them.

     

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