Fixed beam structures are widely used in engineering, and a common problem is determining the load conditions of these structures resulting from impact loads. In this study, a method for accurately identifying the location and magnitude of the load causing plastic deformation of a fixed beam using a backpropagation artificial neural network (BP-ANN). First, a load of known location and magnitude is applied to the finite element model of a fixed beam to create plastic deformation, and a polynomial expression is used to fit the resulting deformed shape. A basic data set was established through this method for a series of calculations, and it consists of the location and magnitude of the applied load and polynomial coefficients. Then, a BP-ANN model for expanding the sample data is established and the sample set is expanded to solve the common problem of insufficient samples. Finally, using the extended sample set as training data, the coefficients of the polynomial function describing the plastic deformation of the fixed beam are used as input data, the position and magnitude of the load are used as output data, a BP-ANN prediction model is established. The prediction results are compared with the results of finite element analysis to verify the effectiveness of the method.

Thin-walled structures (TWS) were widely used in engineering equipment, and may be subjected to impact loads to produce different degrees of structural damage during application. However, it is a difficult problem to determine the impact load conditions for these structural damages. In this study, we developed a novel method of identifying the impact load condition of the thin-walled structure damage, which is based on particle swarm optimization-backpropagation (PSO-BP) neural network. First, the known impact position and velocity are applied to the finite element model (FEM) of the TWS to produce permanent plastic deformation, and to fit the characteristic shape of the deformation is needed by invoking the multivariate polynomial function. Then, the method is devoted to build a basic data set. With impact position and velocity as input and function coefficients as output, a model of extended PSO-BP neural network is established. Besides, the basic sample set is expanded to solve the lack of samples. Ultimately, utilizing the expanded total sample set as training data, function coefficients, impact position and velocity will be outputted. On the basis of the known functional coefficients of deformed surfaces, a model of predictive PSO-BP neural network is established and predicted. Furthermore, we predicted the collision position and velocity using a conventional BP neural network in the same way. Finally, the predicted impact position and velocity is compared with the analysis results of the FEM, which verifies that the PSO-BP neural network algorithm has high accuracy.

The influencing factors of riveting deformation are more complicated, and the specific relationship between the amount of deformation and each factor is difficult to express with general expressions, which is a non-linear problem. Aiming at this problem, this study uses RBF neural network to establish a model of the relationship between the maximum deformation of single nail riveting and various factors. Then, 1000 sample sizes were designed using the LHS method, with 90% of the sample size as training and 10% as testing. Secondly, the secondary development of the finite element software is carried out by using Python language to realize parametric modeling and batch processing. Finally, using the RBF neural network model to predict the maximum deformation of a single nail riveting, the maximum relative error and the average relative error were 8.43% and 2.948%, respectively. The results show that the RBF neural network can be applied in the field of prediction of maximum deformation of riveting and has high prediction accuracy.

No abstract

In view of the complexity of the composite stiffened plate structure, a prediction model between the properties and geometric parameters of the composite stiffened material and the buckling load is established based on the BP neural network. Firstly, the finite element model of composite stiffened plates was established by using Abaqus software, and the buckling load under axial load was studied. Secondly, 500 experimental samples were drawn using the Latin hypercube experiment method, and the corresponding values were obtained based on the software Buckling load value. Finally, 450 experimental samples are selected as the training set and the remaining 50 samples are used as the test set to establish a BP neural network prediction model. The results show that the method of using BP neural network to predict buckling load is effective and correct.