Fatigue-Fractured Surfaces of Epoxy Adhesives and Fractals under Mode I Cyclic Loading

抄録

The effects of rubber modification and adhesive thickness on the fatigue-fractured surfaces of epoxy adhesives under mode I cyclic loading were examined using fractals. When the energy release rate range, ΔG_I, is higher than 100 J/m², the fractal dimension of fractured surfaces becomes high due to rubber modification. The fractal dimension decreases with increasing fatigue crack growth rate, da/dN. The following equation shows the relationship between parameter S(=da/dN·ΔG_I)and fractal dimension D for unmodified and rubber-modified adhesives. log S=log(da/dN·ΔG_I)=α₄·D+β₄ Here, α₄ and β₄ are experimental constants. Regardless of whether the adhesives contain rubber particles or not, the fractal dimension as well as the da/dN-ΔG_I relation is little affected by adhesive thickness.