Study On The Application Of Piezoelectric Energy Collector And Vibration Absorber In Marine Diesel Engine

The marine diesel engine is used as the main power device of the ship,and the vibration and noise generated during the operation of the marine diesel engine seriously affect the safety of the ship body,the service life and the reliability of the instrument and equipment on the ship,and also seriously affect the operational performance of the ship.Therefore,the research on the vibration and noise control of marine diesel engine has become a hot topic.In this paper,a multi-piezoelectric cantilever vibration reduction and noise reduction device is designed based on the 6135 marine diesel engine.The vibration damping principle of the cantilever is equivalent to the spring mass damper,and the vibration energy is collected and converted into electric energy by the piezoelectric effect of the piezoelectric material.The periodic structure of the cantilever beam and the periodic structure of the vibration damping device are designed by combining the band gap theory of the local resonance type phononic crystal,and the piezoelectric energy-collecting performance and the vibration-damping noise-reducing performance of the device are simulated and analyzed,the physical of the vibration-damping energy-collecting device is made,and the vibration-absorbing and energy-collecting experiment is carried out on the marine diesel engine.The specific research work is as follows:Firstly,the mechanical model of the main vibration components of marine diesel engine is analyzed theoretically.The three-dimensional model of diesel engine crankshaft-connecting rod mechanism is established by using the 3D modeling software UG,and the model is introduced into the finite element analysis software COMSOL for mesh generation.The finite element model is obtained by setting the boundary condition and load,and the vibration mode of crankshaft is analyzed by mechanics,and the acoustic pressure of noise produced by crankshaft vibration is analyzed by acoustics.Secondly,the energy band structure and transmission characteristics of local resonant phonon crystal are analyzed theoretically,the thin-plate phonon crystal structure is designed,the phonon crystal model is established and the finite element calculation is done by using COMSOL.The influence of the parameters of the phonon crystal thin plate on the band gap is simulated and the model of the phonon crystal thin plate is established.The energy band structure and the transmission loss of the phononcrystal thin plate are calculated respectively for the mechanics and the acoustics of the phonon crystal thin plate.Then,the theoretical analysis of the piezoelectric effect energy collection and the vibration reduction of the cantilever beam oscillator is carried out,the basic structure of the phonon crystal piezoelectric energy-collecting and energy-damping device is designed,the three-dimensional model of the vibration-damping energy-collecting device is created by the UG,the three-dimensional model is introduced into the COMSOL division grid,the boundary condition is set,The performance of the piezoelectric energy collection and the performance of the vibration reduction and noise reduction of the device are analyzed by the finite element method.In this paper,the physical design of the vibration-damping energy-collecting device is made,and the piezoelectric energy-collecting and vibration-reducing experiment of the diesel engine based on the vibration-absorbing and energy-collecting device is designed and completed.Finally,150 sets of structural parameters are set up within a certain range of changes for different parameters of the device,and the mechanical simulation and transmission loss calculation of each set of parameters are carried out.The BP neural network is trained by the calculated transmission loss and structure data set.The trained BP neural network is used to inverse fit the multi-group structure parameters,and the change between the fitting structure parameters is small.Then the mechanical simulation and transmission loss calculation are carried out based on the fitted structural parameters.In this process,the BP neural network is used to optimize the structure of the energy-collecting device for vibration reduction.