Crack initiation characteristics of brittle materials with I-II mixed mode crack under uniaxial compression

Considering T-stress components under compression, the crack initiation characteristics of HT200 and PMMA under uniaxial compression have been investigated by theoretical analysis and experimental study for central cracked plate (CCP) and compact tension shear (CTS) specimens with I-II mixed mode crack. Crack initiation angles of CCP and CTS specimens under compressive load were theoretical predicted according to modified maximum tangential stress (MMTS) criterion and modified maximum shear stress (MMSS) criterion. The influence of material parameters and specimen geometrical configurations on crack initiation characteristics was illustrated through experiments. It demonstrates that the modified fracture criterion considering T-stress components is more consistent with experiments. Crack initiation angle is related to material properties. Limit load P-L is controlled by K-II under compression for CCP specimen, and P-L of PMMA is less than that of HT200. The closure effect on CTS specimens is less significant than that on CCP specimens.

Automated summary

Through theoretical analysis and experimental study, crack initiation characteristics of HT200 and PMMA under compression were investigated, demonstrating that considering T-stress components in the modified fracture criterion is more consistent with experiments and crack initiation angle is related to material properties.