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目前,J_(Ⅰc)的测试引起了国内外的厂泛重视。三点弯曲试样得到了最广泛的应用。我们曾导出J=(2U/B(W-a) (1)的关系,式中U是试样的应变能。Rice等在[2]中所建议的是另一关系J=2/(B(W-a)integral from n=0 to △aPd△_a (2)其中△_a=△-△_0 (3)△_0是同尺寸的无裂纹试样加载到同一载荷P时的位移。(1)和(2)式虽形式相近但内容不同究竟何者更为正确,很有必要加以澄清。我们的推导是以U=B(W-a)~2f(△)或其等效关系P=B(W-a)~2φ(△)为出发点的,这里不再重复。Rice则假定
At present, the test of J_ (Ⅰc) has aroused extensive attention at home and abroad. Three-point bending specimens have been the most widely used. We have derived the relation J = (2U / B (Wa) (1), where U is the strain energy of the specimen, and the other proposed by Rice et al in [2] is another relation J = 2 / (2) where △ _a = △ - △ _0 (3) △ _0 is the displacement of a crack-free specimen of the same size at the same load P. (1) and ) Although the form is similar but the contents of what is more accurate, it is necessary to be clarified. Our deduction is U = B (Wa) ~ 2f (△) or its equivalent relationship P = B (Wa) ~ 2φ △) as the starting point, no longer repeat here. Rice is assumed