Influence of Macro-Topography on Damage Tolerance and Fracture Toughness of Monolithic Epoxy for Tribological Applications

Abstract

Influence of topographical features on mechanical properties of monolithic epoxy samples has been studied. The topographical features studied include waviness (Wa), roughness average (Ra), root mean square value (Rq), and maximum roughness height (Rmax or Rz). The Rz of as-cast monolithic epoxy samples was 13.93 µm. By treating with velvet cloth, the Rz value significantly decreased to 2.28 µm. The Rz value of monolithic epoxy sample treated with abrasive paper 1200P was 4.85 µm which was also lower than that of as-cast monolithic epoxy samples. However, Rz values significantly increased by treating with abrasive papers 320P and 60P and became 20.32 µm and 39.32 µm, respectively. It was interesting to note that although Ra, Wa, and Rq, all increased by treating the monolithic epoxy samples with abrasive paper 1200P, however, Rz decreased by abrasive paper 1200P. A weight loss of up to 17% was observed in monolithic epoxy samples after the treatment with the abrasive papers. Both V-shaped and U-shaped notches were produced on the surfaces of the samples. The mechanical properties were significantly degraded due to surface notches mainly because of the associated stress concentration effect. The topographical features also influenced the dynamic mechanical properties and fracture mode.