Vibration Characteristic Study And Optimization Of A Tubular Stand-off-layer Damping Structure With Slots

At present,the vibration impact of crawler vehicles is an urgent problem to be solved.Because there are a large number of tubular structures in vehicles,damping treatment for these structures can effectively reduce the vibration impact.Based on traditional constrained damping structure and the National Natural Science Foundation for young scientists of China(Study on the Coupling Mechanism of Physical-mechanical Parameters of Tubular stand-off-layer Damping Structures),dynamic model of the tubular slotted stand-off-layer damping structure was established using complex eigenvalue method.Considering the physical and mechanical properties of viscoelastic materials,dynamic equation were solved using the perturbation method,and the influence of structure parameters changes were analyzed.Finally,the optimization of the damping performance of the tubular structure with slotted stand-off-layer damping was studied.The main researches are given as follows:(1)The phase method was used to fit the overall curves of physical and mechanical properties of damping layer and transition layer materials with the change of ambient temperature and frequency.The empirical formulas of shear modulus G’,loss factor,conversion coefficient of temperature frequency and reasonable selection of reference temperature were discussed for further analysis.(2)Based on the complex eigenvalue method,the vibration characteristics of tubular structures with slotted stand-off-layer were solved.The dynamic equation of the slotted stand-off-layer damping structure was established,and the perturbation method was used to solve the equation,and the natural frequency and loss factor of the structure were obtained.NASTRAN software was used for finite element simulation,and the results were compared with those in the literature.(3)The circumferential and axial tubular slotted stand-off-layer damping structure were respectively processed.The effects of the number of slots in the stand-off-layer,the thickness of the stand-off-layer and the thickness of the constrained layer on the structural vibration characteristics were analyzed.The results show that the stand-off-layer damping structure with slots has a better damping effect.(4)Based on the MATLAB software and hybrid genetic algorithm(HGA),the dynamic optimization of circumferential damping structure with slots was studied.The parameter variables are temperature,thickness of stand-off-layer,number of circumferential slots,gap distance and thickness of constraint layer.The objective functions are maximized structural loss factor,minimum total mass and natural frequency change variables.The multi-objective function is transformed into a single objective function to solve the problem.Finally,the influence of the transition layer thickness and the weight coefficient k_mon the optimization results was discussed.The research in this paper not only broadens the application scope of complex eigenvalue method,but also provides important theoretical support for the design of slotted damping structure and its application in various types of vehicles.