INVESTIGATION OF VISCO-ELASTIC MECHANICAL BEHAVIORS OF UV-CURING RESIN BASED ON FINITE VOLUME METHOD

The complexity of the ultraviolet-curing (UV-curing) polymer system, comprised of various resins, contributes to the uncertainty in its viscoelastic mechanical behaviors as it evolves over time. By using polyurethane acrylate (PUA) as a representative material, the fractional order viscoelastic constitutive is incorporated into the second-order displacement expanded finite volume model to explore the mechanical behaviors of UV-curing resin in this paper. Firstly, the continuity conditions of cell surface and the global stiffness matrix of the numerical model are determined in accordance with loading conditions, enabling the explicit calculation of unknown surface displacements for all cells. To investigate the viscoelastic behavior of UV-curing resin with respect to varying strain rates, a fractional-order finite deformation Kelvin-Voigt viscoelastic model is introduced to establish the stress-strain constitutive relationship. Secondly, parameters of the elastic and viscous components in the constitutive model are determined through uniaxial tensile tests at strain rates of 10⁻⁴, 10⁻³, 10⁻², and 10 s⁻¹. Finally, digital image correlation (DIC) analysis is performed in conjunction with uniaxial tensile tests at various strain rates to compare the experimental results and evaluate the computational accuracy of the numerical model. It is indicated that the established numerical model can effectively predict the visco-elastic mechanical behaviors of light-cured resin under different strain rates, with an average prediction error of 1.98%.