Disk-shaped compact tension test for fracture analysis on pharmaceutical tablets

Pharmaceutical tablets must meet a number of requirements and among them, the mechanical strength plays an important role. The diametral compression test is generally used to evaluate it but can generate unstable failures. Thanks to load-unload cycles applied to the tablets subjected to a DCT test, it was shown that the concept of equivalent linear elastic fracture mechanics usually, can be successfully applied to the Mode I fracture behavior. Within this framework, the equivalent elastic crack growth resistance, commonly called resistance curve (R-curve), of the studied material was obtained and revealed the development of a Fracture Process Zone (FPZ) which is symptomatic of a quasi-brittle behavior. Moreover, the cyclic loading applied during the fracture test revealed the existence of a second dissipative mechanism leading to residual crack opening which seems to be mainly caused by friction phenomenon in the FPZ.