Prediction of buffeting responses of the thin plate under joint action of wave and wind using LSTM and transfer learning

Abstract

To predicate the buffeting responses of long-span sea-crossing bridges under joint action of wave and wind, a thin plate was taken as the example, and a piston-type wave maker was adopted to simulate the second order Stokes wave in a computational domain. Through the large eddy simulation (LES) and dynamic mesh methods, time-histories of wind field and buffeting response of the thin plate under joint action of wave and wind were obtained. Then, the buffeting responses of the thin plate were predicted using the conventional long short-term memory (LSTM), convolutional LSTM (Conv LSTM) and LSTM with attention mechanism (LSTM-AM) neural network models, respectively. Furthermore, the transfer learning (TL) method was introduced, the method to solve a large amount of source task data was established, and a combined neural network model of TL-Conv LSTM-AM was proposed to predict the buffeting responses of the thin plate. The results show that the prediction accuracies of Conv LSTM and LSTM-AM models are both higher than the conventional LSTM model based on the evaluation indexes of determination coefficient (R2) and root mean square error (RMSE). The prediction accuracies of the buffeting responses can be improved significantly when the above LSTM neural network models are combined with the TL method. Also, there are still some deviations between the predicated time-histories and target ones. For the proposed combined model of TL-Conv LSTM-AM, the values of R2 in three directions of the buffering responses are all larger than 0.996 and 0.983 in the high and low turbulent flow fields, respectively. Therefore, the proposed TL-Conv LSTM-AM combined model has the highest prediction accuracy among them. Similar prediction accuracy can be achieved for longer time duration of the testing data set using the proposed combined model of TL-Conv LSTM-AM. The above phenomenon proves that the effectiveness of this proposed combined model in predicting the buffeting responses of the thin plate under joint action of wave and wind.