This paper mainly studies the structure of a carbon fiber reinforced polymer floating raft frame and analyzes its vibration mode. A frame-based floating raft frame is designed, and two floating rafts which are made of carbon fiber reinforced polymer and metal materials, respectively, and have the same size and structure are manufactured. Based on the modal theory of vibration, the Abaqus software is used to carry out the finite element modal analysis of the frames which are made of different materials, and compare the low-order flexible frequency and vibration mode. Later, the experimental modal test results are verified with modal assurance criterion, and the modal experiment is conducted to verify the accuracy of finite element modal calculations. The results show that under the circumstance of the same frame vibration mode, the damping ratio of the carbon fiber reinforced polymer frame is much higher than that of the metal frame. In addition, the carbon fiber reinforced polymer frame presents good vibration absorption performance. The data analysis results provide some reference value for floating raft vibration designers.
This paper mainly deals with the specific damping capacity (SDC) of carbon fibre-reinforced plastics (CFRP) plates with holes of different sizes, positions and quantity control. Through establishing a three-dimensional damping matrix and using the finite element analysis (FEA) and Matlab, numerical calculations were conducted on the SDC of CFRP plates with same layering scheme, and a vibration test as well as a damping analysis was implemented on the CFRP test pieces with middle holes. By comparing the calculation and experimental results, good accuracy was found in predicting the modal frequency as well as SDC of the CFRP vibrations through the three-dimensional damping matrix analysis model. By comparing the modal damping of plates with different hole sizes, it could be found that as the hole size increases, the frequency showed a slowly changing tendency. The SDC of the plates with holes could reach 170% of that of the plates without holes.
Aiming at the poor waveform quality of the new energy grid connected under the traditional PI control strategy, based on the theory of repetitive control method, a compound control trategy is proposed. Through the analysis of the compound control module and simulation, the results show that grid harmonic distortion rate can be reduced about 2% at the same nonlinear load, the compound control strategy can suppress the load disturbance signal effectively, and the simulation results demonstrate the effectiveness of the proposed method.
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