Determining the viscoelastic behavior of polyester fiberglass composite by continuous micro-indentation and friction properties

The purpose of this study is to characterize the influence of specific micro-indentation test methods and frictional behavior on the viscoelastic properties of polyester fiberglass composite. Previous work shows that viscoelastic parameters for neat thermoset polymers can be successfully determined using a recently developed phenomenological model. In this study, similar depth sensing micro-indentation tests were performed on polyester fiberglass composite surface to determine the effect of fiberglass reinforcement on viscoelastic properties of the composite. Data obtained from micro-indentation tests was used to calculate the viscoelastic properties of the composite using the previously developed model, and compared to those of neat polyester. Results show that fiberglass significantly increased the both viscoelastic indentation modulus parameters, E0* and E1*, of the composite. Scratch tests were also performed on this composite, showing a higher coefficient of friction for a diamond stylus in contact with a polyester fiberglass composite than when in contact with a neat polyester. Moreover, the coefficient of friction decreased as the diamond stylus׳s sliding speed increased for the composite. A model is then applied to illustrate that the von Mises stress distribution in the material during a scratch test is dependent on scratch velocity.