基于聚类降阶均匀化的复合材料TCN建模方法及迁移学习策略

TCN Modeling of Composites based on Clustered Reduced-Order Homogenization and Transfer Learning Strategy

  • 摘要: 准确预测复合材料历史依赖性力学响应对于工程应用至关重要,需要考虑细观非均匀场量的演化问题。问题的复杂性令常规有限元分析计算成本居高不下,从而导致细-宏观耦合的多尺度分析难以实现。为此,本文提出一种基于聚类降阶均匀化的复合材料时间卷积网络(TCN)建模方法。基于聚类非均匀变换场分析(CNTFA)理论和循环随机混合式采样策略,利用CNTFA降阶模型生成数据集来训练TCN代理模型,以大幅提升计算效率。为了进一步节约训练成本,针对同类型问题提出迁移学习策略。在源问题TCN模型的基础上,冻结部分残差块,只需喂给少量目标问题数据对剩余残差块参数进行精调,便可获得目标问题的高精度代理模型。所提出的方法保持细观本构模型无关的框架设计,因而通用性较高。最后,针对纤维增强复合材料宏观等效性能进行算例分析。结果显示,在保证较高预测精度的同时,TCN代理模型的在线计算效率较CNTFA模型提升2个数量级。

     

    Abstract: Accurately predicting the history-dependent mechanical response of composites is crucial for engineering applications, as it requires considering the evolution of microscopic heterogeneous field variables. The complexity of this problem leads to prohibitively high computational costs in conventional finite element analysis, making it challenging to achieve micro-macro coupled multiscale analysis. To address this issue, this paper proposes a Temporal Convolutional Network (TCN) modeling method of composites based on clustered reduced-order homogenization. Based on the theory of Clustered Nonuniform Transformation Field Analysis (CNTFA) and a cyclic-random hybrid sampling strategy, the CNTFA model is used to generate datasets for training the TCN surrogate model for a significantly improved computational efficiency. To further reduce training costs, a transfer learning strategy is introduced for similar problems. By leveraging the pre-trained TCN model from the source problem and freezing certain residual blocks, only a small amount of target problem data is required to fine-tune the parameters of remaining residual blocks, yielding an accurate surrogate model for the target problem. The proposed method maintains a framework design independent of microscopic constitutive models, ensuring a wide generality. Finally, a numerical study is conducted on the macroscopic effective properties of fiber-reinforced composites. The results demonstrate that while maintaining high prediction accuracy, the online computational efficiency of the TCN surrogate model is improved by two orders of magnitude compared to the CNTFA model.

     

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