Mechanics of Materials 2010 Part 10 ppt

... the number of load cycles; C the intercept of line along da dN and is of the order of 10 −6 and has units of length/cycle; and n is the slope of the line and ranges from 2 to 10. 10 Equation ... Saouma Mechanics of Materials II Draft 15.3 Variable Amplitude Loading 5 ⇒ N =  a f a i da C[∆K(a)] n =  a f a i da C (σ max − σ min ) n    (∆σ) n ((πa) 1 2 ) n =  8.4 10...

Ngày tải lên: 11/08/2014, 15:21

... Background CDF Number of cycles 0 1 10 9 10 7 A B C D E F (b) 01 CDF Stress 10 9 10 7 A B C D E F (a) Figure 3.4. Schematic of CDF (a) for two different values of N f , (b) as a function of N . has been ... range of frequencies from 30 to 100 0 Hz under the Air Force HCF program at various laboratories are presented in Figure 3.14 for R = 08. Including 800 850 900 950 100...

Ngày tải lên: 03/07/2014, 20:20

... Saouma Mechanics of Materials II Draft 6 FUNDAMENTAL LAWS of CONTINUUM MECHANICS 6.3.2 †Moment of Momentum Principle 25 The moment of momentum principle states that the time rate of change of the ... the total moment of momentum of a given set of particles equals the vector sum of the moments of all external forces acting on the particles of the set. 26 Thus, in...

Ngày tải lên: 11/08/2014, 15:21

... σ 0  a 2r sin θ 2 cos θ 2 sin 3θ 2 (10. 26) 30 Combining the above equations, with Eq. 10. 13-d, 10. 14-d, and 10. 15 we obtain Victor Saouma Mechanics of Materials II Draft 10. 5 Near Crack Tip Stresses ... Crack Surfaces of an Edge Crack: The solution of this problem, Fig. 11.11 is K I = 2P πa C  1+  x a  2  −0.4  x a  2 +1.3  (11.16) Victor Saouma Mechanics of M...

Ngày tải lên: 11/08/2014, 15:21

... showing amplitudes of LCF and HCF fatigue limit stresses. LCF–HCF Interactions 151 10 100 100 0 1 10 100 100 0 10, 000 c = 5 μm, short crack c = 5 μm, long crack c = 500 μm, short crack c = 500 ... of, the co-authors of Kitagawa or El Haddad in the referenced publications. Rather, the respective terminologies are for convenience only. 152 Effects of Damage on HCF Properties 10...

Ngày tải lên: 03/07/2014, 20:20

... in space. However, in precracking of the material in the case of C-shaped specimens, and particularly in the case of notched specimens, the process finds the location of the weakest link and initiates ... establish the HCF limit stress corresponding to a life of 10 6 cycles. Results for the FLS corresponding to 10 6 cycles as a function of the number of LCF cycles are shown...

Ngày tải lên: 03/07/2014, 20:20

... express the combined effects of the gradient of stress at the notch root, the individual contributions of notch root radius and depth of notch, the effect of volume of material being stressed, and ... theory of fracture mechanics. Smith and Miller [10] have determined this limiting value of stress to be  = 05 K th √ d (5.8) where K th is the threshold stress intensity ra...

Ngày tải lên: 03/07/2014, 20:20

... stress distributions ahead of a circular notch of radius r, and of a crack of length a, are shown in Figure 5.23, for three different values of a/a 0 ; 0.1, 1.0, and 10. The thick lines show the ... strength of a material, is due to Lukas et al. [25]. Using linear elastic fracture mechanics, they compared the stress intensity of an edge crack of length l in a plate with that...

Ngày tải lên: 03/07/2014, 20:20

... as a D = a 0  2 a N = a ∗  2 = k 2 t a 0  2 (5.39) 246 Effects of Damage on HCF Properties 0 100 200 300 400 500 10 4 10 5 10 6 10 7 R = –1 R = 0.1 R = 0.5 Predicted, R = –1 Predicted, R = 0.1 Predicted, ... other problems in HCF center around the issue of the effect of odd-shaped inclusions on the FLS of a material. The effects of small defects in materials, particula...

Ngày tải lên: 03/07/2014, 20:20

... lives in excess of 10 6 cycles. These results can be seen better in Figure 6.46 where the predictions for total life are compared with 10 3 10 4 10 5 10 6 10 7 10 3 10 4 10 5 10 6 10 7 R = 0.0, ... 311 –500 0 500 100 0 1500 2000 10 0 10 1 10 2 10 3 A1 A2 B1 B2 C1 C2 σ xx (MPa) Y Position (μm) Figure 6.50. Axial stress as a function of depth from surface for...

Ngày tải lên: 03/07/2014, 21:20