The effect of geometry on fracture strength measurement using DCDC samples

An empirical model for estimating fracture toughness using the DCDC geometry

“…This instability is due to nonlinear geometric effects associated with buckling. No rapid jumps in crack length were noted during the experiments (Nielsen et al 2012). Reviewing the experimental data, six of the seven samples with cracks that exceeded this critical length show a slight decrease in the applied stress beyond a normalized crack length of ~7.…”

“…The 2D finite element simulation approach previously discussed (Nielsen et al 2012) was modified to investigate the effect of sample geometry and material properties on the DCDC fracture test. The modified method uses a prescribed critical stress intensity factor to estimate the applied stress as a function of the crack length.…”

“…The simulation method was also applied to the DCDC experimental geometry and material properties given by Nielsen et al (2012) (Table 1, line 2). Similar to experimental observations, the computational results show an initial region of increasing stress followed by a plateau region with smaller changes in the fracture stress ( Fig.…”

“…Adding nonlinear geometric effects to the long crack model is discussed by We have previously created a finite element simulation scheme to study the DCDC test (Nielsen et al 2012). The method was originally developed to study the evolution of the bending moment during the test, but it was determined that fracture toughness could be directly estimated from the output.…”

“…The test is stable when the compression required to grow the cracks increases with crack length. A detailed description of a displacement-controlled DCDC experiment is given by Nielsen et al (2012).…”