Crack-Tip Opening Displacement Test is carried out to test the Fracture toughness in order to check whether a material is fit for tough working conditions or not. It measures the deformation before undergoing failure in a pre-cracked sample. Spectro has developed skills to carry out CTOD test efficiently as per BS 7448 Standard.
It is practiced on those materials which undergo plastic (irreversible) deformation before it encounters failure. The testing material resembles the original one, but the dimensions can be reduced proportionally.
The crack tip opening can be calculated from the depth of the crack and opening at the mouth of the notch. Depending on the material used, the fracture can be brittle or ductile that can be concluded from the graph.