An evaluation of fatigue limit of notched specimen of a C/C composite

2018 International Conference on Material Strength and Applied Mechanics

材料科学;力学

Makabe, C.^1 ; Fujikawa, M.^1 ; Ferdous, M.S.^2

Faculty of Engineering, University of the Ryukyus, Okinawa

903-0213, Japan^1

Department of Mechanical Engineering, Bangladesh Army University of Science and Technology, Saidpur

5310, Bangladesh^2

关键词: C/C composites;    Carbon fiber reinforced carbon composites;    Damage condition;    Different sizes;    Fatigue Limit;    Fatigue strength;    Notched specimens;    Stress concentration factors;   

Others  :  https://iopscience.iop.org/article/10.1088/1757-899X/372/1/012001/pdf
DOI  :  10.1088/1757-899X/372/1/012001

来源: IOP

【 摘 要 】

The fatigue strengths in notched specimens of carbon fiber reinforced carbon composites (C/C composites) were investigated. The fatigue limit was measured by S-N curves and load increase tests. The value of fatigue limit obtained by those methods was almost the same. Slits of several sizes were cut on both sides of a test section, and different sizes of slit length were chosen. Also, specimens with blunt-notches were used to compare the fatigue strength. The weakest fatigue limit was obtained in the case of specimens with blunt-notches. However, the stress concentration factor of those is smaller than that of slit specimens. The relationships between fatigue strengths and specimen shapes were analyzed by stress distribution. The effect of slit configuration on fatigue strength was then discussed regarding the experimental consequences. Consequently, it was discussed that the fatigue strength of the present specimens was determined depending on the damage conditions in the vicinity of the notch and on the crack initiation behavior. It is expected that the tendency of the S-N curve and fatigue limit was related to the shear damage and shear mode of the crack growth.