Research On Damping Performance Of Constrained Damping Structures Based On Non-obstructive Particle Damping Technology

In order to improve the vibration reduction performance of the traditional constrained damping structure,this paper introduced Non-Obstructive Particle Damping technology and designed the constrained damping structure based on NOPD technology.Through the cantilever beam vibration test,the composite loss factor and time domain attenuation curve of the above structure were studied,which was combined with the theoretical analysis of energy consumption of two-particle sphere collision and the state analysis of particle motion.And the effects of particle filling ratio,density,particle size,excitation force and ambient temperature on the vibration reduction performance of NOPD damping structure were discussed.Through the research,the following conclusions are drawn:Firstly,according to the theoretical model of collision process between two spheres,the influence of particle filling ratio,particle size and density on the vibration response and composite loss factor of NOPD damping structure was studied.The results show: with the increase of filling rate,the composite loss factor of NOPD damping structure increases at first and then decreases,and when the filling rate is 50%,the loss factor reaches the highest value of 0.1447,which is 60.78% higher than that of constrained damping structure without filling particles(hereinafter referred to as unfilled damping structure).When the filling rate of particles was before 50%,almost all the particles in the cavity had a large displacement change.With the continuous increase of the filling rate,the space for free movement in the cavity was decreased which made the total energy consumption of particles with energyconsuming movement reduce.The particle size of steel ball with equal diameter which increased from 0.8 mm to 2.0 mm,filled in NOPD damping structure,and the composite loss factor only differed by 0.0012.With the increase of particle size and the number decreases.Although the energy consumption of single collision and friction increased,the number decreased which made the change of total energy consumption be not obvious.The composite loss factor of NOPD damping structure increased with the increase of density.And the maximum value of composite loss factor was 0.1654 when filled with particles,which was 86.05% higher than that of the structure without particles.With the increase of particle density,the energy of single friction and collision loss increased,while the number of times does not change,which made the total energy consumption increase.Secondly,combined with the proportion and initial state of mixed particles,the influence law of filling mixed particles on the vibration reduction performance of NOPD damping structure was explored.The results showed: The composite loss factor of NOPD damping structure filled with mixed particles of 2.0mm and 0.8mm steel balls was0.1461～0.1591 under different mixing ratios and initial conditions,which was 0.4%～10.0%higher than that of the structure filled with only 2.0mm steel balls.That is because mixed particles with different sizes had lower pores and larger contact area,which increased the elastic-plastic deformation ability of particles and lost more energy.The composite loss factors of mixed particle structure filled with 2.0mm shot and 2.0mm steel ball in different initial states were 0.1615,0.1579 and 0.1564,which were further increased by 1.51%,1.09%and 2.36% respectively,compared with NOPD damping structure filled with the same mixing ratio and different particle sizes of the same material.However,the composite loss factor of the structure filled with mixed particles with different materials and different particle sizes was up to 0.1653,which was further increased by 12.46% compared with the structure filled with 2.0mm steel ball particles.Finally,the influence of ambient temperature on NOPD damping structure showed that with the increase of ambient temperature,the composite loss factors of NOPD damping structure and unfilled damping structure showed a trend of increasing first and then decreasing.The maximum composite loss factors of the two structures at 25℃ were 0.1025 and 0.1491,which were 25.61%,19.51%,21.07% and 6.24%,5.57% and 7.31% lower than those at-25℃,0℃ and 50℃.The damping performance of traditional constrained damping structure was greatly influenced by environment,while NOPD damping structure improved the adverse effect of environmental temperature.