A new method is proposed to identify structural damages based on the power spectral density sensitivity analysis. The responses of the structure under stationary and random excitations are obtained using pseudo excitation method, and then the sensitivities of power spectral density with respect to the structural damage parameters are obtained similarly. Finite element model updating method is adopted to identify the structural damages. A numerical example of a shearing structure demonstrates the satisfactory results obtained from the present method.

Sintered SiC ceramics with difficulty, and its production process and production are more expensive, lower sintering temperature of SiC ceramics and look for new low-cost production process is the focus of materials research workers. Re-crystallization of SiC components of the raw materials requirements of high purity, can not add sintering aids, sintering temperature up to about 2450°C). In this paper, by improving and optimizing the existing production process, to lower the sintering temperature of the new methods and ideas, the study shows that: β-SiC will be added to the sintered α-SiC slurry, and the best particle size ratio of α: β = 15:1 mixture, at the same time, according to re-crystallization of SiC sintering theory, the fine particles (β-SiC, has played the role of sintering agent) adsorption in the coarse particle (α-SiC, the role of the support skeleton) and can greatly reduce the SiC Sintering temperature (50-100°C), and to improve the purity of α-SiC, the most economical way to prepare a high-density, high oxidation resistance, high impact resistance, high strength, high mechanical properties of recrystallized SiC powder .