Study on Analysis Method of da/dN-ΔK Curves Based on Probability Statistics Theory

Through the logarithmic interpolation performed on the data of da/dN and ΔK from the results of crack growth rate test with high strength steel, a p-da/dN-ΔK curve analysis method(da/dN-ΔK method) based on probability statistics theory was established. Compared with the a-N method, it is found that under any reliability p within the effective range of ΔK, the p-da/dN value obtained by da/dN-ΔK method is higher than that obtained by a-N method. When ΔK is the maximum value of 100 MPa·m^0.5, the p_0.99-da/dN value obtained by da/dN-ΔK method is about 25% higher than that obtained by a-N method. The p-da/dN-ΔK curves obtained by da/dN-ΔK method coincide well with the distribution of da/dN and ΔK in the actual test, which means da/dN-ΔK method is an effective way to obtain the p-da/dN-ΔK curves of materials.