Fracture Toughness

Fracture Toughness Laboratory

WMT&R has established a world-renowned reputation for dependable Fracture Toughness Testing. Our state-of-the-art Fracture Lab is designed for the high volume quick turn around projects demanded by the Aerospace, Power Generation, Petroleum, Nuclear, and Automotive 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 240+ servo 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.

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.

Here at WMT&R's Fracture Toughness & Fatigue Testing Laboratory we most often perform 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.

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.

Surface-Crack tension (SCT) testing is conducted to ASTM E-740 and is relied upon to estimate the load-carry ability of sheet or plate components with a flaw that could possibly occur during actual use. Our fracture toughness department routinely conducts this test to cryogenic temperatures down to -450°F. Research uses for this test include studying failure characteristics of cracks under simulated service conditions.

In addition to fracture mechanics based testing this department also specializes in conducting various other types of test including peel test, flexure, shear (single, double, slotted or LAP) and rising load testing to name a few.

Reports are automatically generated using our innovative database system, which can be transferred directly and securely to your database via an Electronic Data Interface (EDI).

Our Fracture Toughness Testing Capabilities include:

Proprietary state of the art software and unrivaled facilities for performing:

Our subsidiary in the UK, WMT&R, Ltd., offers an impressive array of Fracture Toughness Tests to meet your needs.