Study On The Viscoelastic Matereials And Dynamic Properties Of Partial Constrained Layer Damping Structure

Viscoelastic damping materials and damping structures have been widely used in various fields to reduce vibration and noise,but the constraining layer and the damping layer are not necessarily 100% laid on the base surface because of many limitations of conditions in practical engineering.But in many projects,the damping effect is required.So it is necessary to study the damping performance of partial constrained layer damping structure.In this paper,the basic properties and dynamic mechanical properties of Qtech T501 viscoelastic damping materials are studied,and the dynamic mechanical properties of viscoelastic damping materials are fitted by using dynamic mechanical analysis(DMA)test results.Single point hammer test is carried out on the partial constrained layer damping structure sample,and modal analysis of the partial constrained layer damping structure model is carried out by using the finite element analysis software ANSYS,and dynamic mechanical properties of the sample and the model of partial constrained layer damping structure under the boundary conditions with simply supported edges are studied and analyzed from two angles of the coverage rate of constraining layer and damping layer and the constraining layer thickness respectively.Through the above research,the following results are obtained:First,the basic properties of Qtech T501 viscoelastic damping materials are as follows: The gel time of Qtech T501 viscoelastic damping material is 185 s and the drying time is 38 min,which can improve the construction efficiency;it’s solid content is 95.5%,belongs to the high solid content environmental protection material;it’s Shore A hardness of 35,indicating that the material is softer;Tensile strength is 1.62 MPa,breaking elongation is 526.95%,tearing strength is 5.54kn/m,but because the material is not used as a structural material,so it is not particularly demanding for its mechanical properties.The analysis of dynamic mechanical properties of Qtech T501 viscoelastic damping materials shows that the temperature and frequency have a great influence on the energy storage modulus and the loss factor of the material..And with the help of DMA test results,the relationship between the energy storage modulus and the loss factor of Qtech T501 viscoelastic damping material with the frequency at reference temperature of 25 ℃ is fitted,the coefficients of the fitting formula are 0.9991 and 0.9976 respectively,which shows that the fitting formula has higher precision.The results of the single point hammer test of the partial constrained layer damping structures show that the vibration duration of the structure is generally within the range of 0.05-0.15s;when the coverage rate of constraining layer and damping layer is increased from 40% to 80%,the analysis of the maximum amplitude,vibration acceleration spectrum and total vibration acceleration level value indicates that the vibration reduction effect of the sample is improving continuously,when the coverage rate of constraining layer and damping layer of samples is increased from 80% to 100%,the effect of the structure quality on the vibration acceleration is great,so the analysis results of different indexes are not the same.But after considering the quality factor and economic factor synthetically,it is considered that the 80%-damping layer laying area is more reasonable.When the thickness of the constraining layer increases from 2cm to 8cm,all the indexes indicate that the damping effect of the structure is enhanced,and the performance of the structure in the first two gradients is improved most obviously.The finite element simulation results of partial constrained layer damping structures show that the structural composite loss factor is the largest when the coverage rate of constraining layer and damping layer is 80%;and the composite loss factor of the structure increases with the increase of the thickness of the constraining layer,but the increasing amplitude decreases gradually.The shear deformation of damping layer in the partial constrained layer damping structure is the most intense in its central position.In practical engineering,the shear deformation of the central position can be increased by adjusting the coverage rate of constraining layer and damping layer and the restraining effect of the damping layer is strengthened by increasing the thickness of the constraining layer to achieve the engineering vibration damping requirement.