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    基于BP神经网络的GH4065合金高温变形行为预测模型

    High-Temperature Deformation Behavior Prediction Model of GH4065 Alloy Based on BP Neural Network

    • 摘要: 在变形温度1 150~1 350 K、应变速率0.001~1 s−1条件下对GH4065合金进行高温压缩试验,获得了真应力-真应变曲线;基于反向传播(BP)算法构建了合金高温变形神经网络模型,采用神经网络结构自寻优方法确定了模型的拓扑结构,对BP神经网络模型预测合金高温变形行为的准确性进行了验证,并与考虑真应变影响的Arrhenius变参数本构模型模拟结果进行了对比;基于该神经网络模型建立了真应变、变形温度、应变速率与真应力的连续映射关系。结果表明:构建的BP神经网络模型为3-10-11-1结构,采用训练、验证数据预测得到的真应力与试验结果的平均相对误差分别为3.54%和2.77%,相关系数分别为0.997 4和0.994 8,模型能够精确预测合金的高温变形行为;BP神经网络模型对GH4065合金高温变形真应力的预测精度高于Arrhenius变参数本构模型(平均相对误差9.54%,相关系数0.979 1)。

       

      Abstract: High-temperature compression tests of GH4065 alloy were carried out under conditions of deformation temperature of 1 150–1 350 K and strain rate of 0.001–1 s−1. The true stress-true strain curves were obtained. By the back propagation (BP) algorithm, the neural network model for high-temperature deformation of the alloy was constructed, and the topological structure of the model was determined by self-optimizion method of neural network structure. The accuracy of the BP neural network model in predicting the high-temperature deformation behavior of the alloy was verified, and was compared with that of Arrhenius variable parameter constitutive model considering true strain effect. The continuous mapping relationships among the true strain, deformation temperature, strain rate and true stress were established by the BP neural network model. The results show that the BP neural network model had a 3-10-11-1 structure. The average relative errors between the true stress predicted by the training and validation data and the test results were 3.54% and 2.77%, respectively, and the correlation coefficients were 0.997 4 and 0.994 8, respectively, indicating that the BP neural network model could accurately predict the high temperature deformation behavior of the alloy. The prediction accuracy for the true stress of GH4065 alloy during high temperature deformation of BP neural network model was higher than that of the Arrhenius variable parameter constitutive model ,whose average relative error was 9.54% and correlation coefficient was 0.979 1.

       

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