Sharp crack to determine fracture toughness
As there are more complicated welding joints for heavy steel plate used in large boilers, pressure vessels or ship hulls and decking, the CTOD test is use to determine fracture toughness of a material with a crack. Fracture toughness is the critical stress intensity factor of a sharp crack where propagation of the crack suddenly becomes rapid and unlimited.
Our expert technical team use it to determine crack tip opening displacement to inspect unstable fracture. Plastic deformation can occur prior to failure, which allows the tip of a crack to stretch and open, hence ‘tip opening displacement’.
The distance between the opposite faces of a crack tip at the 90° intercept position. The position behind the crack tip at which the distance is measured is arbitrary but commonly used is the point where two 45° lines, starting at the crack tip, intersect the crack faces. While the CTOD test was developed for the characterisation of metals, it has also been used to determine the toughness of non-metallic such as weldable plastics.
Large scale tensile testing is a commonly used test to quantify the elastic modulus, yield- , ultimate-, and fracture-strength of materials.
However, while these tests provide valuable insights into the overall material properties, they average out the effects of each constituents such as the different phases or interfaces.
To quantify the properties of a single phase or interface, miniature tensile testing can be used to quantify the mechanical properties of individual interfaces or phases within a material, as demonstrated in the below image.
In addition, measurements on the microscale can be used to detect and investigate single plastic deformation mechanisms
Application of CTOD test
Micro-tensile testing are used to quantify the mechanical properties of individual interfaces
Determining the engineering stress and other properties of a material or part.
Micro-tensile testing are used to quantify the mechanical properties of individual interfaces
Determining the engineering stress and other properties of a material or part.
Talk to us today
Our expert testing team can calculated from the depth of the crack and opening at the mouth of the notch with our CTOD test. With that information, we can help you to determine if our materials are brittle or ductile.
For more information on our CTOD test, call us or send us an enquiry today.
