Mode III Interlaminar Fracture Toughness
The Mode III interlaminar fracture toughness of a composite can be measured using the split cantilever beam (SCB) geometry. Here, a cracked beam similar to the DCB specimen is used. Two aluminium bars are bonded to the sides of the sample to increase its stiffness and prevent twisting during the test. A thin layer of paint is applied to the top and bottom of the sample to monitor crack advance. The sample is loaded in the vertical plane, typically at 1 mm/min.
Crack propagation is usually stable and the load-displacement trace is similar to the Mode I DCB trace.