基于跨层级协同强化的CFRP孔边挤压强度预测

Prediction of bearing strength at the hole edge in CFRP based on cross-hierarchical synergistic reinforcement

  • 摘要: 针对碳纤维增强基复合材料(CFRP)孔边挤压强度试验数据量不足以充分学习各特征影响机制,导致难以准确预测的问题,提出一种基于跨层级协同强化(Cross-Hierarchical Synergistic Reinforcement, CHSR)的CFRP孔边挤压强度预测方法。首先,由于输入特征较多而试验数据量有限,难以一次性全面挖掘所有特征蕴含的知识,采用积木式策略将特征按复杂度划分为低层级与高层级特征;其次,构建低尺度模型即低层级特征映射模型,通过神经网络预训练提取低层级特征知识,并将知识协同迁移至高尺度模型的固定域;然后在高尺度模型固定域锁定底层知识的基础上,通过强化学习动态优化高层级特征表征权重与阈值,并实现跨层级梯度协同传播与孔边挤压强度预测,提升复杂特征耦合下的强度预测精度;最后,以X850材料螺栓连接孔边挤压强度预测为案例,进行变铺层样本预测,结果显示,两种铺层均值误差分别为0.10%、0.48%,标准差误差分别为2.64%、3.50%,许用值误差分别为0.29%、0.13%,CHSR相比传统机器学习算法精度提升效果明显,能够实现对X850孔边挤压强度的高精度预测。

     

    Abstract: To address the challenge of insufficient experimental data on the bearing strength at the hole edge of carbon fiber-reinforced polymer (CFRP) composites, which hindered the full understanding of the influence mechanisms of various features and led to difficulties in accurately predicting extrusion strength, a CFRP extrusion strength prediction method based on Cross-Hierarchical Synergistic Reinforcement (CHSR) was proposed. Firstly, due to the limited experimental data volume relative to the high dimensionality of input features, it is challenging to comprehensively extract knowledge embedded in all features simultaneously. To address this, a modular strategy is employed to partition features into low-level features and high-level features based on their complexity. Secondly, a low-scale model, namely the low-level feature mapping model, was constructed. The low-level feature knowledge was extracted through neural network pre-training, and the knowledge was collaboratively transferred to the fixed domain of the high-scale model. Subsequently, on the basis of locking the underlying knowledge in the fixed domain of the high-scale model, reinforcement learning was applied to dynamically optimize the weights and thresholds of high-level feature representations, enabling adaptive refinement of their contributions to the prediction task. Then, cross-hierarchical gradient collaborative propagation was implemented to harmonize feature inter-actions between low-level and high-level domains, thereby achieving accurate prediction of hole-edge compressive strength under complex feature coupling. Finally, taking prediction of X850 material bearing strength at the edge of the bolted con-nection hole as a typical case, variable layup sample prediction was carried out. The results show that the mean error of the two paving layers is 0.10%, 0.48% the standard deviation error is 2.64%, 3.50% and the allowable value error is 0.29%, 0.13%. Compared with the traditional machine learning algorithm, CHSR can achieve high precision prediction of X850 bearing strength at the hole edge.

     

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