Modeling the large inelastic deformation response of non-filled and silica filled SL5170 cured resin

In recent years, important efforts have been focused on rapid production of tools using Rapid Prototyping and Manufacturing (RP&M) technologies such as the Stereo-Lithography Apparatus (SLA). One of the applications is the development of rapid polymer tooling such as dies for injection molding. For these applications, optimal thermal as well as mechanical properties of final tools are of significance. In order to characterize the mechanical response of materials made by SLA, a standard set of material tests, including uniaxial tension and compression tests under different strain rates and different temperatures, was conducted for both silica filled and non-filled resin. In this paper, the mechanical response of the non-filled SL5170 cured resin is discussed in terms of an elastic-viscoplastic material model. Further, a new model for silica filled SL5170 cured resin was developed to estimate the stress-strain relationship of the composite. This composite model is an extension of the elastic-viscoplastic model for non-filled resin to include the elastic deformation of the silica particles. The stress-strain curves predicted by the models under homogeneous deformation show good agreement with the experimental results.