The Research And Application For The Mechanical Properties Of Microcellular Polyurethane Elastic Material

With the development of the high-speed trains,especially the subway and urban rail transit has been rapid development,ballast track has many difficult problems to solve such as the critical speed, stability and railway harshness. Because of its good comprehensive performance ballastless track has widely used in high speed railway, subway, and inter-city rail transit. Rail fastening which match the ballastless track not only fixed orbit but also povides the vibration reduction/elastic and damping vibration isolation. Because of microcellular polyurethane elastic plate has better mechanical properties and processing properties, microcellular polyurethan is widely used in WJ-8 fasteners, and replace the rubber plate as the main vibration of track components. However, in the engineering applications, the domestic research for the viscoelastic of microcellular polyurethane is rare, however, its dynamic viscoelasticity research is particularly important in the engineering application of the material. Due to its dynamic viscoelasticity research is important for the material, so it is necessary to comprehensive its mechanical properties.This issue takes the microcellular polyurethane materials as the research object. By quasi-static experiments and DMTA experiments, discussion the elastic and viscoelastic of the microcellular polyurethane elastomer. In this paper, the main content of the work is as follows:First, this paper summarizes the application of microcellular polyurethane materials in rail transit, the automotive industry, engineering machinery and other fields of application for f microcellular polyurethane elastic materials. The current research status of home and abroad dynamic and static mechanical properties.Secondly, cited the hyperelastic material constitutive model to characterize the microcellular polyurethane elastic material nonlinear static mechanics performance. For the study of existing hyperelastic material constitutive model applicability for microcellular polyurethane elastomer, and carried on the microcellular polyurethane elastomer tensile, compression and pure shear mechanics experiments, to obtain the curve of stress and strain experiment data. According to equivalent principle of converting experimental data compression and biaxial experiments experimental data. Using the microcellular polyurethane elastomer to obtain experimental data of existing superelastic material constitutive model for fitting, then get the corresponding constitutive model parameters, and through the error analysis of the applicability of the hyperelastic material constitutive model is analyzed and evaluation.Third, the mechanical properties of microcellular polyurethane elastomer experimental research. DMTA experiment method is applied in this article to research the microcellular polyurethane elastomer energy storage modulus, loss factor and temperature, the relationship for the frequency and amplitude, then discussion the influence of different factors on the effect of dynamic mechanical properties of microcellular polyurethane elastomer. Through the discussion about the existing viscoelastic constitutive models, using different order number of generalized Maxwell constitutive model of viscoelastic materials to fit the experimental data, then obtained the corresponding constitutive model parameters, and through the error analysis to determine the accurate model order.Lastly, using the hyperelastic and viscoelastic mechanics experimental data to determine the corresponding constitutive model parameter values, the microporous polyurethane elastic plate used in WJ-8 fastener system for finite element simulation, and has carried on the dynamic and static products experiment to WJ-8 fastener. By comparison with the error analysis about the experimental results and simulation results shows that the simulation precision of the hyperelastic constitutive model from low to high followed by, M-R, Yeoh model and Ogden third-order model, four order generalized Maxwell viscoelastic constitutive model of materials storage of stiffness and loss factor of simulation error values were 5.2% and 9.1% respectively, the precision is closer. The last of this paper summarizes the work has done, and the subsequent should do the work was also discussed.