SEDL / STP / STP1406-EB / STP11667S

An X-Specimen Test for Determination of Thin-Walled Tube Fracture Toughness

Hsu, HH
Institute of Nuclear Energy Research (INER), Chiaan,

Chien, KF
Institute of Nuclear Energy Research (INER), Chiaan,

Chu, HC
Institute of Nuclear Energy Research (INER), Chiaan,

Kuo, RC
Institute of Nuclear Energy Research (INER), Chiaan,

Liaw, PK
The,

Pages: 13    Published: Jan 2002

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Abstract

A new fracture toughness measurement method, named an X-specimen test that is based on the curved compact-tension test, was proposed to assess the fracture toughness of thin-walled tubing materials like Zircaloy fuel cladding. This technique offers applications of fracture mechanics for testing thin-walled tubes, which do not meet the requirements of the American Society for Testing and Materials standards in terms of the specimen configuration and loading state. The finite-element analysis was conducted to evaluate the feasibility of applying the X-specimen test to the measurement of cladding fracture toughness and to develop a relationship between the stress intensity factor and crack extension. Then fracture and fatigue tests were performed employing a hydraulic mechanical testing machine. The J-integral value was evaluated using the experimental results of the applied load, loadline displacement, and crack extension.

By means of a backtracking method, the stress intensity solutions were computed using fatigue results. A J-integral value of about 82 kN/m was obtained for Zircaloy fuel cladding. A comparison of the present test results and literature data shows that the X-specimen test is suitable for a quantitative evaluation of the fracture behavior of thin-walled tubing materials.