Cracks growth direction

Figure 7.43 Fatigue fracture face, showing crack growth direction. (Reproduced from COM 1999 and 2005 with permission from the Metallurgy Society of CIM)...

Fig. 7.3 Examples of crack profiles in AI2O3/33 vol.% SiC whisker composite subjected to static and cyclic tensile loads (in a four-point bend configuration) in 1400°C air. From Ref. 22. Crack growth direction is from right to left, (a) Static crack growth at K 4-5 MPaVnT (b) Cyclic crack growth at R = 0.15 and vc = 0.1 Hz in the AK range 3.5-5 MPaVfiT...

Fig. 12 Theoretical analysis of initial crack growth directions. In a first step, the three-dimensional elastic contact stress field is calculated within the polymer body under small amplitude reciprocating micro-motions. A two-dimensional analysis of crack initiation is subsequently carried out using the calculated stress values in the meridian plane of the contact (Oxz). Average shear (rm) and tensile (crm) stresses are calculated for different locations in the contact and for different orientations, a, with respect to the normal to the contact plane...

Fig. 4 Fracture surface of an ESC specimen in water at 3.5 MPa. The arrow indicates the crack growth direction.

Figure 5. Residual stresses perpendicular to the weld direction also crack growth direction stresses measured on the M(T) specimen used for obtaining the crack growth rates.

Figure 5.2. Schematic illustration of grain structure in a rolled plate, along with designations for the rolling or longitudinal (L), transverse (T), and short-transverse or thickness (S) directions, and the associated cracking planes and crack growth directions per ASTM Method E-399 [3].

The orientations of the crack plane and crack growth direction are defined in terms of these definitions for example, LT designates a specimen that has its crack in the TS plane and is to be loaded in the L direction. 

Figure 5.41 Fatigue fracture face showing crack growth direction. (Figure originally pub-hshed in Reference 26. Reproduced with permission of the Canadian Institute of Mining, Metallurgy and Petroleum, www.cim.org.)...

Modell applied load parallel to the crack plane and the crack growth direction... 

Fig. 12 Theoretical analysis of initial crack growth directions. In a first step, the three-...

Consider stable crack growth conditions such as a double cantilever beam specimen loaded by forcing a wedge along the crack growth direction. Initially the... 

The crack opening and softening process was based on Hillerborg s (1976) approach, which defined the energy required to open a unit area of crack, as a material parameter, using brittle fracture concepts. Also the prediction of crack growth direction was based on Rots and Blaauwen-draad (1989) researches. The influences of cracks normally appear as high stiffness reduction of structures which is one of the important factors in the applications of this type of materials and it must be consider for the mechanical model. 

Owing to the cross sections observations, it appears that no crack growth is possible for the dented surface. This could be explained by the fact that the crack growth direction is opposite to the load direction. In that case it was demonstrated [25] that the crack can not propagate and is going to be closed. It could be also mentioned that compressive residual stresses induced by the indentation process also protect the surface around the dent and so reduce the shear stress influence. For the smooth surface, as the pressure profile is modified by the... 

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