FATIGUE CRACK GROWTH TESTING
TESTING TO ASTM E647, ASTM E467 & MORE
At Zhejiang Guojian Testing Technology Co., Ltd (CCT) , we perform Fatigue Crack Growth Testing to determine the rate at which a preexisting crack grows under varying crack tip driving force over time. The test is also known as crack propagation or da/dN testing, and we use compliance and DC potential drop crack length measurement techniques. We perform these tests on materials under both K or load control. Additionally, we can provide advanced custom testing methodologies to characterize threshold and full Region I, Region II and Region III crack growth.
SCOPE OF FATIGUE CRACK GROWTH TESTING
At Zhejiang Guojian Testing Technology Co., Ltd (CCT) 's lab in Zhejiang, China, our experienced team provides fatigue crack growth testing services that adhere to ASTM E647 and ASTM E467 standards. Our testing capabilities include variable-amplitude fatigue crack growth (spectrum testing), dwell testing, and custom customer waveforms. We offer various test options, such as Adjusted Compliance Ratio, compression precracking, K-control, and constant Kmax testing.
Our lab can perform testing at temperatures ranging from -76°F (-60°C) (using liquid nitrogen) up to 1800°F and at absolute loads between 100 lbf and 5000 lbf. We offer constant load, increasing and decreasing ΔK, and constant Kmax control methods. To accurately measure and account for crack closure, we use advanced techniques such as crack opening load measurement.
For fatigue crack growth rate analysis, we typically use C(T), M(T), and SEN(T) specimens, which are expertly prepared in-house by our machine shop.
Additional Resources
SPECIMEN PREPARATION
Zhejiang Guojian Testing Technology Co., Ltd (CCT) provides fatigue crack growth testing services in Zhejiang, China, using various techniques such as compliance and DC potential drop crack length measurement. ASTM E647 and ASTM E467 standards are followed for the testing, and variable-amplitude fatigue crack growth testing (spectrum testing), dwell testing, and custom customer waveforms are available. The testing can be performed at temperatures between -76°F（-60°C） and 1800°F, and at absolute loads between 100 lbf and 5000 lbf. Zhejiang Guojian Testing Technology Co., Ltd (CCT) 's in-house machine shop can prepare specimens in all standard geometries, including C(T), M(T), SEN(T), and surface flaw specimens. Starter notches are produced using wire EDM.
Contact Zhejiang Guojian Testing Technology Co., Ltd (CCT) for a quote or more information on fatigue crack growth testing.
ABOUT THE FATIGUE CRACK GROWTH TEST
At Zhejiang GuoJian Testing Technology Co., Ltd. (China National Center for Quality Supervision and Test of Standard Parts), the fatigue crack growth test is utilized to evaluate the safety and reliability of materials by subjecting samples to repeated loading and unloading. The test analyzes the crack growth rate and measures the resistance of materials to stable crack extension under cyclic loading conditions. Constant load or K-controlled parameters are typically used to develop fatigue crack growth rates from the very slow threshold regime to the fast growth rate region.
The automated fatigue crack growth testing system employs MTS closed loop servo-hydraulic load frames controlled by the industry-leading FTA ADWin-based system. Both compliance and DC Potential Drop (PD) methods are available for monitoring crack length. The results of these tests are represented by a curve displaying the crack growth rate as the cyclic stress intensity factor (ΔK) is varied.
Fatigue crack growth test reports include the following information:
· Raw da/dN versus ΔK data
· A da/dN – ΔK plot
· as appropriate
our CAPABILITIES
· Test Method – ASTM E647, ASTM E467
· Control Methods – Constant Load, increasing and decreasing ΔK, constant Kmax
· Loads – up to 100,000 lbs.
· Temperature – between -76°F（-60°C） (liquid nitrogen) and 1800°F
· Test Specimens – C(T) compact tension; M(T) middle tension, SEN(T) single edge notch tension, Kb Bar surface flaw and corner crack
· Fixturing – C(T) and M(T), SEN(T), Button Head and threaded Kb Bar specimen geometries in a range of sizes
