Preparation And Properties Of Constrained Damping Composites

Because of the nature of deformation energy, damping materials is widely used in modern aviation, aerospace, marine, transportation, heavy machinery and other areas to control broadband random noise, the vibration and noise excitation. But the most of the viscoelastic materia lthe modulus of elasticity is very low, they can not direct a project in the structural material, it must adhere to their treatment needs for reducing vibration and noise damping components on the composition of composite structures, can play a damping to reduce the noise. The basic types of composite structures with free damping and constrained damping, so what works derived free damping materials and constrained damping material.The constrained layer damping occurs greater structural loss when the shear deformation due to vibration,and therefore has been more widely used.in vibration and noise control engineering.The purpose of this paper is to prepare constrained damping composites and study the properties. In the experiment, the constrained damping composites is usually by the primary constraint damping materials, binding layer and damping layer. the material of the primary and constrained layer.This is to select stainless steel sheet and aluminum as the primary and the constrained layer material. The choice of this paper is the epoxy resin and polyethylene polyamine curing system, and glass fiber reinforced epoxy resin system as the damping materials.We can get the following conclusions from the test and analysis:(1) When the choice of damping layer materials is polyethylene polyamine curing epoxy resin system, when the curing agent polyethylene polyamine content (mass ratio) was 13%, the damping properties of the material is good. The peak of the maximum loss factor is over than 0.85; (2) When choosing the polyethylene polyamine epoxy curing system, when increasing the damping layer thickness butreducing the loss factor of the system. The peak of the maximum loss factor is 0.5688. The peak insertion loss of the whole system can achieve near-20dB, and the average insertion loss is less than-15dB; (3) When the damping layer material chosen for the fiber-reinforced epoxy resin damping material, with the damping layer thickness increases the damping loss factor of the order emerged gradually increasing trend. The peak of the maximum loss factor is 0.3542. The peak insertion loss of the whole system can achieve near-20dB, and the average insertion loss is less than-15dB; (4) When choosing steel as the constrained layer material, the loss factor is larger than the the loss factor of choosing aluminum as the constrained layer material. The difference of about 0.1;(5) New grooved extension of constrained damping layer damping performance compared to an increase of only non-expansion slot constrained damping layer structure and no increase in the new extension with a slot constrained layer damping structures have good damping properties. the difference of the loss factor can reach more than 0.5.