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In order to identify structural damage locations and extent, a method based on ridge estimation and modal strain energy is presented in this paper. First, structural modal strain energy is given and a modal strain energy sensitivity damage equation is obtained. Then, considering the TikhonovTT regularization theoryTT, a ridge estimation method is proposed to solve the damage equation and ridge parameter of the method is optimized. Simulation results demonstrate that the proposed damage detection method based on ridge estimation and modal strain energy can identify structural damage locations and extent with good accuracy.

In order to study Particle Swarm Optimization (PSO) algorithm and structural damage diagnosis, a method based on PSO algorithm and Evidence theory is presented in this paper. First, structural frequency and modal strain energy are considered as two kinds of information sources, and frequency change method and modal strain energy method are utilized to extract damage information. Then, evidence theory is utilized to integrate the two information sources and preliminarily detect structural damage locations. Finally, the PSO algorithm is used to identify structural damage extent. An improved PSO algorithm is also presented. Simulation results show that the evidence theory can identify the suspected damage locations, and the PSO algorithm can precisely detect the damage extent. It can also be observed that the improved PSO algorithm is obviously better than the simple PSO algorithm.

In order to solve structural damage identification problem, a damage identification method based on improved Particle Swarm Optimization (IPSO) is presented. First, structural frequency and modal strain energy are utilized to obtain damage information. Then, evidence fusion theory is utilized to integrate the information and preliminarily identify structural damage locations. After the damaged locations are determined, Particle Swarm Optimization (PSO) is used to identify structural damage extent. Some improved strategies are presented to enhance the search efficiency. The simulation results demonstrate that the proposed method can estimate the damage locations and extent with good accuracy.

Ba0.5Sr0.5TiO3film was successfully fabricated by micro arc oxidation of titanium plate in aqueous solution containing Sr(OH)2and Ba(OH)2for 25 minutes. X-ray diffraction , energy dispersive spectrometer and scanning electron microscopy were used to characterize the crystalline structure, elements composition and surface morphology and HP4284 capacitance prober was used to analyze the dielectric properties of the film. The micro arc oxidation film is mainly composed of tetragonal Ba0.5Sr0.5TiO3 phases and possesses both high dielectric constant of 454.2 and low dielectric loss of 0.052 at the frequency of 100Hz.The surface morphology appeares smooth and homogeneous except that some holes are uniformly distributed outwardly.

Pure titanium plates as anode and mixture of solutions containing 0.2M Sr(OH)2and 0.2M NaOH as electrolyte, titanium plates were microarc-oxidated for 10 minutes. X-Ray Diffraction (XRD) analysis indicated that SrTiO3film was successfully deposited. The MAO film is composed mainly of tetragonal SrTiO3phases and found to possess high dielectric constant of 371.0 at the frequency of 1 kHz. Scanning Electron Microscopy (SEM) and portable roughness tester were used to characterize the surface morphology and roughness values(Ra), The influences of electrolyte concentration, current density and frequency on the surface morphology of SrTiO3film were investigated in detail . several rules were drawn from the results. A kinetics expression was established for the growth of film thickness and agreed well with the experimental results.

In order to solve the damage detection problem, a damage detection method based on strain energy and evidence theory is presented in this paper. First, an evidence theory method is proposed to identify structural damage locations. Then, structural modal strain energy is utilized to quantify structural damage extents. In general, structural strain energy dissipation should be equal to the change of modal strain energy, according to this theory, a new energy equation is deduced, and structural damage extent can be obtained through the solution of the equation. The simulation results show that the method can perfectly identify damage locations and extents. Therefore, the proposed method is effective for the structural damage identification.