Optimized Neural Network Prediction Model of Shape Memory Alloy and Its Application for Structural Vibration Control

The traditional mathematical model of shape memory alloy (SMA) is complicated and difficult to program in numerical analysis. The artificial neural network is a nonlinear modeling method which does not depend on the mathematical model and avoids the inevitable error in the traditional modeling method. In this paper, an optimized neural network prediction model of shape memory alloy and its application for structural vibration control are discussed. The superelastic properties of austenitic SMA wires were tested by experiments. The material property test data were taken as the training samples of the BP neural network, and a prediction model optimized by the genetic algorithm was established. By using the improved genetic algorithm, the position and quantity of the SMA wires were optimized in a three-storey spatial structure, and the dynamic response analysis of the optimal arrangement was carried out. The results show that, compared with the unoptimized neural network prediction model of SMA, the optimized prediction model is in better agreement with the test curve and has higher stability, it can well reflect the effect of loading rate on the superelastic properties of SMA, and is a high precision rate-dependent dynamic prediction model. Moreover, the BP network constitutive model is simple to use and convenient for dynamic simulation analysis of an SMA passive control structure. The controlled structure with optimized SMA wires can inhibit the structural seismic responses more effectively. However, it is not the case that the more SMA wires, the better the shock absorption effect. When SMA wires exceed a certain number, the vibration reduction effect gradually decreases. Therefore, the seismic effect can be reduced economically and effectively only when the number and location of SMA wires are properly configured. When four SMA wires are arranged, the acceptable shock absorption effect is obtained, and the sum of the structural storey drift can be reduced by 44.51%.

Fixed and Base Isolated Framed Structures: A Comparative Study

Necessity of constructing multi-storied buildings is increasing these days. But they are more prone to severe damage due to earthquakes. Base isolation is one of the most powerful tools pertaining to the passive structural vibration control technologies. The structure above the ground, is separated from the effects of earthquake forces by introducing a mechanism that helps the structure to hover. This project deals with analysis of 10 storey RCC, Steel and Composite structures of different shapes with and without base isolation in various seismic zones by Response Spectrum Method using ETABS software. Lead rubber bearings designed as per UBC97 was used for base isolation. Plus shape was found to be most suitable for base isolation for RC structure, whereas for steel and composite structures rectangular and hollow shapes were found suitable. It was also observed that concrete structure performs best when base isolated, compared to other structures.