Composite plate structures are prone to damages caused by low-velocity impacts. To locate these impacts, many impact localization methods using fiber Bragg grating (FBG) sensors have been developed. However, it is dif...
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Composite plate structures are prone to damages caused by low-velocity impacts. To locate these impacts, many impact localization methods using fiber Bragg grating (FBG) sensors have been developed. However, it is difficult to achieve the high localization accuracy when impact response signals are acquired by a FBG sensing system with a low sampling frequency in previous studies. In this paper, a two-step localization method using wavelet packet energy characteristics is proposed to address this problem. The proposed impact localization method consists of the collection of impact samples, feature extraction, and two-step localization. To collect impact samples, a FBG sensing system with a sampling frequency of 5 kHz and four FBG sensors is uti-lized to acquire the response signals induced by the low-velocity impacts on a carbon fiber reinforced plastic (CFRP) plate. Then, a new impact feature, which is sensitive to the low-velocity impacts and can eliminate the influence of the impact height, is defined according to the wavelet packet energy characteristics. Finally, a two-step localization method is designed to achieve the accurate localization for the impacts, in which the first step is the impact area identification based on a feature database and the second step is the impact localization based on the stochasticfractalsearch (SFS) algorithm. The results of four sets of experiments prove the effectiveness and satisfactory performance of the proposed impact localization method for the low-velocity impact localization on the CFRP plate.
This article develops a control scheme for automatic generation control (AGC) of a realistic isolated power system comprising of combined cycle gas turbine (CCGT) plant and wind turbine generator (WTG). Robust AGC ope...
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ISBN:
(纸本)9781538644911
This article develops a control scheme for automatic generation control (AGC) of a realistic isolated power system comprising of combined cycle gas turbine (CCGT) plant and wind turbine generator (WTG). Robust AGC operation of the hybrid system is done by secondary control action in association with airflow and temperature control. Integral-derivative with filter coefficient (IDF) controller as the secondary, airflow and temperature controlling unit for the test system outperforms other classical controllers for variant perturbations. A novel control strategy has been proposed where IDF in association with integral (I) controller in different combination for the three controlling action has been proposed for the perturbed isolated system. The proposed combination satisfactorily mitigates the frequency and temperature deviation of the test system. The same combination has been simulated for random wind variation in WTG plant against low to high perturbation. Simulation results authenticate the efficacy of the proposed control strategy.
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