The transition from extremely brittle to very ductile behaviours of creeping materials is discussed, where analogies with power-law hardening materials are pointed out. Considering Norton's Law as a viscous constitutive law, it is possible to define a generalized stress-intensity factor K^c ―characterizing the intermediate asymptotic behaviour under steady-state creep conditions― with physical dimensions depending upon the Norton stress exponent n. In the two limit cases of creep resistant materials (n≅1) and creep sensitive materials (n ≫ 1), K^c assumes respectively the dimensions of an elastic stress-intensity factor ($F{L}^{-3/2}$) and of a stress ($F{L}^{-2}$). Such a dimensional transition, with consequent stress-singularity attenuation, is completely analogous to that occurring through the introduction of a fractal stress-intensity factor (K^c)*, when the influence of microstructural disorder is considered.

讨论了蠕变材料从极脆性到非常韧性的过渡，并指出了与幂律硬化材料的类比。将诺顿定律视为粘性本构律，可以定义广义应力强度因子K ^c（表征稳态蠕变条件下的中间渐近行为），其物理尺寸取决于诺顿应力指数n。在抗蠕变材料（两个极限情况下Ñ ≅1）和蠕变敏感材料（Ñ  »1），ķ ^Ç假定有一个弹性的应力强度因子的分别的尺寸（$F{\mathrm{大号}}^{-3/2}$）和重音（$F{\mathrm{大号}}^{-2}$）。当考虑到微结构紊乱的影响时，这样的尺寸转变以及随之而来的应力奇异性衰减完全类似于通过引入分形应力-强度因子（K ^c）*发生的尺寸过渡。