203 一方向CFRPの非主軸疲労強度と等寿命線図の同定(OS6-(1) 複合材料の変形と破壊およびマルチスケール計算技術,オーガナイズドセッション)

概要

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The effect of stress ratio on constant amplitude fatigue behavior of a unidirectional CFRP laminate has been examined. Applicability of a rational fatigue life prediction method based on constant fatigue life diagram has also been discussed. First, constant-amplitude fatigue tests were performed at room temperature on coupon specimens with different fiber orientations at different values of stress ratio. The experimental results show that the fatigue strength of the unidirectional composite becomes lower for fatigue loading with a larger value of alternating component, regardless of fiber orientation. The stress amplitude becomes largest for the fatigue loading at the critical stress ratio that is equal to the ratio of compressive strength to tensile one. Second, the anisomorphic constant fatigue life diagram was tested which allows efficient construction of constant fatigue life diagram on the basis of the static strengths in tension and compression and the reference S-N relationship for the critical stress ratio. The method was found to be applicable to the fatigue in the fiber direction, while it failed for the other off-axis fiber orientations.
2009-08-25