基于纤维拔出粘结界面力学响应预测模型的钢纤维混凝土三维高效损伤分析方法

Efficient 3D damage analysis method for steel fiber reinforced concrete based on prediction models for the mechanical response of bonding interface during fiber pullout

  • 摘要: 针对钢纤维混凝土(SFRC)细观损伤模拟中界面参数取值的难题,在对189组单纤维拔出试验数据进行汇总分析的基础上,采用深度神经网络构建了纤维拔出的粘结界面力学响应预测模型,并结合贝叶斯优化算法和5折交叉验证来搜索预测模型的最佳超参数;利用该预测模型直接确定界面单元的粘结滑移本构,提出了考虑基体、纤维和纤维-基体界面的高效三维三相SFRC损伤分析方法。本文建立的界面参数预测模型在训练集上的R2大于0.95,而在测试集上大于0.93,表现出良好的泛化能力;相应的损伤分析方法在单纤维拔出和三点弯曲梁算例中的求解用时分别为1.51分钟和13.40分钟,较既有对照方法减少了99.7%和89.9%。研究结果表明:本文方法克服了SFRC界面本构参数取值方法的局限性,有效解决了现有SFRC数值方法存在的网格划分复杂、界面参数取值模糊、收敛困难和计算成本高的问题,为实现工程尺度SFRC结构的高效损伤分析提供了一种新方案。

     

    Abstract: To address the problem of interfacial parameter determination in the meso-scale damage simulation of steel fiber reinforced concrete (SFRC), this study collected and analyzed data from 189 single fiber pullout tests to develop deep neural network-based models for predicting the mechanical response of the bonding interface during fiber pullout. Their optimal hyperparameters were tuned via the Bayesian optimization algorithm combined with 5-fold cross-validation. Furthermore, an efficient 3D three-phase SFRC damage analysis method was proposed to explicitly simulate the matrix, fibers, and fiber-matrix interface, with the bond-slip constitutive parameters of the interfacial elements derived directly from these prediction models. The developed interfacial parameter prediction models demonstrate excellent generalization capability, achieving R2 values exceeding 0.95 on the training set and 0.93 on the test set. The proposed damage analysis method requires only 1.51 and 13.40 minutes to solve the single fiber pullout and three-point bending beam examples, respectively, marking time reductions of 99.7% and 89.9% compared to existing benchmark methods. The results show that the proposed method overcomes the limitations of the current approaches for SFRC interfacial constitutive parameter determination, and effectively solves the persistent problems in SFRC numerical methods, such as complex mesh generation, ambiguous interface parameters, poor convergence, and high computational cost. Thus, it provides a novel solution for the efficient damage analysis of SFRC structures at the engineering scale.

     

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