An application of these functions is shown in Fig. 2, a b. Figure 2: Fatigue in ceramics, a and a PC polymer, b shown by Q*, L, M In Fig. 2 it can be seen again that each line (here, ( ) a N W / * Δ -line) belonging to the families Q* corresponds to a given stress range. What is more, all lines in Qand Q* show a high correlation coefficient 2R given in Figs. 1 and 2. Consequently, because of the revealed specific linear presentation of the fatigue behaviour of a given material or its linear fatigue tendency at a given stress range, we can reduce significantly the readings made in each test and hence, its frequent intermittence. This makes it possible not only to shorten fatigue testing times, but to make the step between the different combinations of loading conditions (in terms of sets of fatigue-loading parameters: stress ranges, frequencies, R-ratios, temperatures, mediums) smaller, and thus to make the analyses and predictions more precise. A new method will be proposed in this study leading to an eventual reduction in the number of readings during different fatigue tests applied to a high-strength spring steel, and a specific data presentation. Also an attempt will be made to apply the function =) log(da dN ( ) ( ) a N f W / * logΔ to fatigue in ceramics and polymers expressing linearly their fatigue tendency at a given stress range, as a first step towards using the new method for these classes of materials. W*1: R2 = 0.999 W*2: R2 = 0.9994 W*3: R2 = 0.9994 W*4: R2 = 0.9983 W*5: R2 = 0.9908 W*6: R2 = 0.9992 R3 2 = 0.9239 R4 2 = 0.8641 R1 2 = 0.7688 R2 2 = 0.6617 R5 2 = 0.841 R6 2 = 0.8596 1.00E-11 1.00E-07 1E-11 0.000001 0.1 Q*:ΔW*(a/N) m3/2/cycle; L: KImax MPa m1/2 da/dN, m/cycle M, Air, y1 M, Water, y2 SC-f, Water,y3 SC-f, Air, y4 SC, Water,y5 SC, Air, y6 Q* L W*1: y1 = 0.0773x0.8296, R2 = 0.9986 W*2: y2 = 0.0443x0.8114, R2 = 0.9891 1E-10 1E-06 0.01 1E-10 0.000001 0.01 Q*:ΔW*(a/N)m3/2/cycle; M:ΔK MPa m1/2 da/dN, m/cycle Long cracks, y1 Short cracks, y2 Q* M a b
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