Abstract: The viscoelastic elastomer has a strong viscoelasticity when it flows inside a shock absorber. The start-up flow models for simulating and studying a viscoelastic elastomer in the orifice and gap of shock absorber have been rarely reported. A fractional Maxwell model with quasi-property is proposed to study the start-up flow of viscoelastic elastomer shock absorber. The start-up flows in the orifice and gap of shock absorber are simplified by unidirectional accelerated flows in a pipe and between two parallel plates of which one is accelerating and the other is at rest. The fractional Maxwell model is developed using finite difference method with real-world initial and boundary conditions. The eproposed model was proved by test. The numerical and test results indicate that the fluid simulated by the fractional Maxwell model had good viscoelasticity, and its stress increase linearly; the curvatures of flow velocity distribution curve of Maxwell model decrease with the increase in the model parameters α, β and ζ; the shape of start-up flow of viscoelastic elastomer in the orifice captured by the test system evolves from a flat shape to a parabolic shape, of which the variation trend is the same as with the result simulated by the fractional Maxwell model; and the simulated maximum fluid level and maximum curvature distance of the fractional Maxwell model are in good agreement with the test results. The maximum errors are 4.79% and 4.67%, respectively. The results show that the proposed fractional Maxwell model can be used to simulate the start-up flow characteristics of viscoelastic elastomer in the orifice or gap of a shock absorber. Key

Key words: shockabsorber, viscoelasticelastomer, fractionalMaxwellmodel, start-upflow, numericalsolution