compacttension

CompactTension refers to a type of fracture mechanics test specimen and loading configuration used to evaluate the fracture toughness and crack-growth resistance of materials. The specimen is a rectangular plate with a notch or fatigue pre-crack, typically mounted in a testing machine and loaded in tension through a pair of pins or grips. The opening-mode (Mode I) loading drives crack propagation from the notch as the load increases.

Geometrically, a CT specimen has a defined width (W), a thickness (B), and a crack length (a) measured from the notch tip. The notch is created with precision machining and a fatigue pre-crack is propagated to a known length before testing. Tests can be monotonic or cyclic, and crack length is monitored during loading by optical methods or compliance measurements. The geometry and crack size are essential inputs for data reduction.

The primary outputs of a CT test are fracture toughness metrics, such as K_IC, or alternative measures like the J-integral or crack-tip opening displacement (CTOD). Using standard data-reduction procedures, the measured load, crack length, and specimen dimensions are converted with geometry factors to yield the toughness value. The results are used to assess material resistance to brittle or rapid crack propagation and to compare materials or processing routes.

Standards and applications: Compact tension tests are governed by international standards that specify specimen geometry, notch and crack-initiation requirements, testing procedures, and data-reduction methods. ASTM E399 is a widely cited standard for plane-strain fracture toughness of metallic materials, with analogous ISO and regional standards applicable to other materials. CT testing is common in metals, ceramics, polymers, and composites for both research and quality-control purposes.