The topographical features of fractured tensile, flexural, K<sub>1C</sub>, and impact specimens of monolithic epoxy have been studied and correlated with mechanical properties and surface features of sampl...The topographical features of fractured tensile, flexural, K<sub>1C</sub>, and impact specimens of monolithic epoxy have been studied and correlated with mechanical properties and surface features of samples before fracture. The topographical features studied include waviness (W<sub>a</sub>), roughness average (R<sub>a</sub>), root mean square value (R<sub>q</sub>), and maximum roughness height (R<sub>max</sub> or R<sub>z</sub>). As surface notches generate triaxial state of stress, therefore, the crack propagation is precipitated resulting in catastrophic failure. Although surfaces can be examined before fracture for any deleterious topographical elements, however, fractured surfaces can reveal finer details about the topography. It is because, as discussed in this article, surfaces with specific topography produce fracture patterns of peculiar aesthetics, and if delved deeper, they can further be used to estimate about the topography of surfaces before fracture. In addition, treating the samples with surfaces of specific topography can help improve the mechanical properties of monolithic epoxy.展开更多
Influence of topographical features on mechanical properties of monolithic epoxy samples has been studied. The topographical features studied include waviness (W<sub>a</sub>), roughness average (R<sub&g...Influence of topographical features on mechanical properties of monolithic epoxy samples has been studied. The topographical features studied include waviness (W<sub>a</sub>), roughness average (R<sub>a</sub>), root mean square value (R<sub>q</sub><sub>)</sub>, and maximum roughness height (R<sub>max</sub> or R<sub>z</sub>). The Rz of as-cast monolithic epoxy samples was 13.93 μm. By treating with velvet cloth, the R<sub>z</sub> value significantly decreased to 2.28 μm. The R<sub>z</sub> 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 R<sub>a</sub>, W<sub>a</sub>, and R<sub>q</sub>, all increased by treating the monolithic epoxy samples with abrasive paper 1200P, however, R<sub>z</sub> 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.展开更多
文摘The topographical features of fractured tensile, flexural, K<sub>1C</sub>, and impact specimens of monolithic epoxy have been studied and correlated with mechanical properties and surface features of samples before fracture. The topographical features studied include waviness (W<sub>a</sub>), roughness average (R<sub>a</sub>), root mean square value (R<sub>q</sub>), and maximum roughness height (R<sub>max</sub> or R<sub>z</sub>). As surface notches generate triaxial state of stress, therefore, the crack propagation is precipitated resulting in catastrophic failure. Although surfaces can be examined before fracture for any deleterious topographical elements, however, fractured surfaces can reveal finer details about the topography. It is because, as discussed in this article, surfaces with specific topography produce fracture patterns of peculiar aesthetics, and if delved deeper, they can further be used to estimate about the topography of surfaces before fracture. In addition, treating the samples with surfaces of specific topography can help improve the mechanical properties of monolithic epoxy.
文摘Influence of topographical features on mechanical properties of monolithic epoxy samples has been studied. The topographical features studied include waviness (W<sub>a</sub>), roughness average (R<sub>a</sub>), root mean square value (R<sub>q</sub><sub>)</sub>, and maximum roughness height (R<sub>max</sub> or R<sub>z</sub>). The Rz of as-cast monolithic epoxy samples was 13.93 μm. By treating with velvet cloth, the R<sub>z</sub> value significantly decreased to 2.28 μm. The R<sub>z</sub> 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 R<sub>a</sub>, W<sub>a</sub>, and R<sub>q</sub>, all increased by treating the monolithic epoxy samples with abrasive paper 1200P, however, R<sub>z</sub> 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.
