WMT&R has a world-renowned reputation for dependable Fracture Toughness Testing. Our state-of-the-art Fracture Lab is designed for the high volume, quick turnaround projects demanded by the aerospace, automotive, power generation, and medical industries.
Fracture Toughness Tests are generally performed on specimens containing a flaw and this requires an operation, called precracking, to induce a flaw of a specific specification. Precracking can be performed on any of WMT&R's 375+ servo-hydraulic test machines, which cover a range of load capacities up to a 1,000,000-lb. fatigue load. The actual crack, which initiates at the top of a machined notch, is generally measured using various automatic techniques including EPD and Compliance.
Fracture Toughness tests are performed at temperatures ranging from liquid helium to over 2000°F under various controlled conditions or atmospheres including salt water, argon, vacuum, and high humidity.
WMT&R's Fracture Toughness & Fatigue Testing Laboratory most often performs the KIC Test per ASTM E-399 which includes disc shape, arc tension, arc bend, single-edge bend, and compact tension. Regarding compact tension testing, we are equipped to perform tests on sizes ranging from .25" thick, up to 4.25" thick for most applications. We have also machined and tested steel compact tension specimens up to 8" thick weighing 1000 lbs.
Fracture Toughness test frame
Additional fracture based services include JIC, KIE - Surface Crack Tension, KR, R Curve, KIV - Short Rod and Short Bar, K-EE - Equivalent Energy, CTOD - Crack Tip Opening Displacement; KISCC and K-Salt Stress Corrosion.
WMT&R conducts KR, R-Curve testing to ASTM E-561 on both compact specimens C(T) and center-cracked tension panels M(T). We have the unique ability to test large M(T) panels at cryogenic temperatures. The KR, R-Curve test provides valuable data about the toughness development as a crack is stably propagated under an increasing intensity factor K. R-Curves and applied K Curves are used to predict the critical stress intensity that will cause the onset of unstable fracturing.
Chevron Notch Short Rod/Short Bar is another type of Fracture Toughness specimen with which we have extensive machining and testing experience. WMT&R has the machining and testing expertise to handle a wide range of specimen sizes from 0.25″ to 2.0″ in the B dimension. The fracture toughness determined by this test shows the resistance of a material to fracture from gradually advancing steady state crack, utilizing a severe tensile constraint, in a neutral environment. A KIV, KIVJ or KIVM value may be assigned to estimate the correlation of failure stress and defect size.
Fracture Toughness Specimen