Numerical evaluation of a 3-D J-integral and comparison with experimental results for a 3-Point bend specimen

Abstract A J- integral ( J ) for the pointwise description of the fracture driving force along a 3-D crack front is studied for the three-point bend specimen. Results of a 3-D nonlinear finite element analysis are used to compute J along the crack front. The analytical values are compared to experimental ‘mean’ values derived from the recorded load and crack mouth opening displacement. The J - integral is found to be path independent when area integrals are added to the line integrals. The J - values at the specimen centerplane are slightly larger than the experimental ‘mean’ J- values and decrease rapidly near the free surface. A linear relationship between J and crack tip opening displacement (CTOD) is present at each point along the crack front in this specimen.

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