Zhang Jinguang

PID Control of Multisources Complex Excitations Active Vibration Isolation System: An Improved Particle Swarm Optimization Algorithm

Active vibration isolation technology is the key technique to solve the vibration isolation problems related to the multisources complex excitations vibration isolation system. The electromagnetic actuators-based multisources complex excitations active vibration isolation system is built. Additionally, in view of the complex structure and strong coupling of the system, the least-squares method to identify and obtain the mathematical model of the vibration isolation system is adopted. Furthermore, this paper also sets up the acceleration feedback-based PID control model for multisources complex excitations active vibration isolation system, proposes an improved particle swarm optimization (PSO) algorithm of dynamic inertia weight factors used to optimize parameters of the built PID control model, and conducts simulation analysis. The simulation results show that, compared with the passive system before the control, the multisources complex excitations active vibration isolation system under the PID control has the far less peak-to-peak amplitude of acceleration which is transmitted to the foundation and has the much better vibration isolation effect. Finally, the paper conducts experimental verification, which demonstrates that active vibration control effect is identical to the simulation results and the vibration control effect is significantly improved.

Reconstruction of fiber Bragg grating strain profile used to monitor the stiffness degradation of the adhesive layer in carbon fiber–reinforced plastic single-lap joint

The adhesive-bonded joint of carbon fiber–reinforced plastic is one of the core components in aircraft structure design. It is an effective guarantee for the safety and reliability of the aerospace aircraft structure to use effective methods for monitoring and early warning of internal failure. In this article, the mapping relation model between the strain profiles of the adherend of the carbon fiber–reinforced plastic single-lap adhesive joint and the stiffness degradation evolution of adhesive layer was achieved by finite element software ABAQUS. The fiber Bragg grating was embedded in the adherend between the first and second layers at the end of the adhesive layer to calculate the reflection spectrum of fiber Bragg grating sensor region with improved T-matrix method for reconstruction of the adherend strain profile of fiber Bragg grating sensing area with the help of genetic algorithm. According to the reconstruction results, the maximum error between the ideal and reconstructed strain profile under different tension loads did not exceed 7.43%, showing a good coincidence degree. The monitoring method of the stiffness degradation evolution of adhesive layer of the carbon fiber–reinforced plastic single-lap joint based on the reconstruction of the adherend strain profile of fiber Bragg grating sensing area thus was figured out.