低秩矩阵引导支持向量机的RC框架IDA曲线预测

LOW-RANK MATRIX GUIDED SUPPORT VECTOR MACHINES FOR IDA CURVE PREDICTTION OF RC FRAME

  • 摘要: 增量动力分析(IDA)曲线考虑了地震输入的不确定性,能合理反映出结构的抗震性能。但其计算过程需要大量的非线性时程动力分析,因而计算效率不高。机器学习方法已被证明能较好地解决这一问题,但当训练数据规模较大时,由于其训练过程涉及求逆矩阵导致计算效率依然不高。为此,该文提出一种低秩矩阵引导支持向量机(LRLS-SVMR)的新方法克服此类方法的不足。在大规模训练数据下,LRLS-SVMR能利用Nystrom近似理论建立一个小规模低秩核矩阵,用于近似大规模原核矩阵。这使得其训练过程只需求解小规模系数矩阵的逆,进而能极大地提高计算效率且保持较高的预测性能。为了验证该方法的准确性和高效性,基于22,037个钢筋混凝土(RC)框架在地震作用下的响应数据,分别与支持向量机(LS-SVMR)和传统有限元方法进行对比。结果表明LRLS-SVMR能准确预测RC框架的最大层间位移角和IDA 曲线,其计算效率比LS-SVMR快了近140倍,比传统有限元方法快了近66,000倍。

     

    Abstract: Incremental dynamic analysis (IDA) curves contain the uncertainty of seismic input and can reasonably reflect the structural seismic performance. However, its computation process involves a large amount of nonlinear time-history dynamic analyses and thus is computationally expensive. Machine learning (ML) methods have been proven to be a good solution to this problem, but their computational cost is still expensive when the size of training data is large due to the training process involving finding the inverse matrix. To this end, this paper proposes a novel method called low-rank matrix-guided least squares support vector machines for regression (LRLS-SVMR) to overcome these shortcomings. With large-scale training data, LRLS-SVMR is able to build a small-scale low-rank kernel matrix using Nystrom approximation theory for approximating the large-scale original kernel matrix. This allows the training process to only solve the inverse of the small-scale coefficient matrix, which in turn can greatly improve the computational efficiency and maintain high prediction performance. The accuracy and efficiency of the proposed method are verified through a comparison with support vector machines (LS-SVMR) and conventional finite element method (FEM) based on 22,037 seismic response data of reinforced concrete (RC) frames. The results show that the proposed LRLS-SVMR can accurately predict RC frames’ maximum inter-story drift and IDA curves. Its computational cost is nearly 140 times faster than LS-SVMR and 66,000 times faster than FEM.

     

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