以提高大截面Z型材四轴滚弯成形精度为目的，通过综合考虑材料属性、几何特征和成形半径等因素对回弹的影响，建立了引入中性层偏移的大截面Z型材弯曲回弹解析模型，研究了7075-O和7475-O铝合金Z型材在不同滚弯成形半径下的回弹规律，并进行滚弯成形实验验证。结果表明，与忽略中性层偏移影响的型材回弹预测经验模型相比，基于中性层偏移的回弹预测模型能够准确预测大截面Z型材的回弹量，在相同的曲率半径下，预测回弹变形的最大相对误差从11.681%减小到3.347%。
This paper focuses on improving the forming precision of Z-shaped profiles with large-section in the four-roll bending process. An analytical springback model is established for Z-shaped profiles with large-section by introducing neutral layer shift, considering the influence of material properties, geometric parameters, and forming radii on the springback. The bending springback laws of 7075-O and 7475-O aluminum alloy Z-section profiles under different forming radii are studied, and roll bending tests are carried out to validate the springback model. The results indicate that compared with the empirical model which ignores the influence of neutral layer shift, the proposed model based on neutral layer shift can accurately predict the springback for Z-shaped profiles with large cross-section. The maximum relative error of predicting springback deformation for Z-shaped profiles with the same radius of curvature changes from 11.681% to 3.347%.
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