Full-range stress intensity factor solutions for clamped SENT specimens

- The stress intensity factor K solutions were reinvestigated for clamped SENT specimens.
- A general, full-range analytical solution of K was obtained for H/W≥3 with accuracy of 0.25%.
- The corrected K solution obtained previously for BS 8571 was shown accurate for crack sizes of a/W≤0.925.
- The actual valid ranges of three FEA results of K were redefined.
- A simple closed-form solution of K was proposed for clamped SENT specimens with H/W = 10.

Single edge notched tension (SENT) specimen with clamped ends has been receiving increasing attention worldwide as a low-constraint specimen to measure less-conservative fracture toughness of pipeline steels in the oil and gas industry. Several SENT test methods were developed, but the solutions of stress intensity factor K used are different. The existing K solutions are thus reviewed and evaluated in this paper for the clamped SENT specimens, and then a full-range analytical solution of K is developed as a function of full-range crack sizes (a/W) and specimen aspect ratios (H/W). From this result, a simple closed-form solution of K is obtained particularly for H/W = 10, as used by the current SENT toughness test methods. The proposed full-range K solutions are validated using different numerical results and error analyses, and thus can be used generally to meet the needs of different SENT testing for determination of fatigue crack growth rate or fracture toughness in the low-constraint conditions.