Dynamic Effects on Fracture Surface Formation in Brittle Polymers: (1st Report, Examination of Surface Roughness)

Fracture dynamics of Homalite-100, PMMA and epoxy were studied. Fracture surfaces were examined by a roughness meter to correlate the surface roughness A with such fracture parameters as crack velocity a and crack extension resistance R∗. High-speed photography of fracture caustic images gave those values. Correlations between λ and those parameters have shown that, although λ depends on d or on R∗, λ is not a unique function of one of those parameters. It is found that λ has the best correlation with the product R∗.a, i.e., dissipated energy per unit crack front and unit time.