And stress intensity factor

Various test geometries may be used to determine values of the fracture energy, G,c, and stress-intensity factor, KIc, at the onset of crack growth and the more common ones are illustrated in Fig. 1. 

Wu X.R. and Carlsson A.J. (1991). Weight Functions and Stress Intensity Factor Solutions. Pergamon Press, Oxford. 

Some commonly used specimens and stress intensity factor solutions are given in ASTM Method E-399 on fracture toughness testing [2]. Stress intensity factor solutions for other geometries are given in handbooks by Sih et al. [4] and Tada et al. 

Figure 3. General relationship between stress-corrosion-crack velocity (v) and stress intensity factor (K)...

The parametric curves in Figures 6.8 to 6.11 can be used individually to select hybridization ratios to satisfy a particular design requirement or they may be used jointly to satisfy two or more design requirements simultaneously, for example, frequency and impact resistance. Comparable plots can be generated for other structural components, such as plates or shells. Also plots can be developed for other behavior variables (local deformation, stress concentration, and stress intensity factors) and/or other design variables, (different composite systems).This procedure can be formalized and embedded within a structural synthesis capability to permit optimum designs of intrapiy hybrid composites based on constituent fibers and matrices. 

Figure 12.14 Crack growth rate versus stress dependenceofthecrackgrowthratefromonthe intensity factor for (a) a silicon nitride [88] and stress intensity factor. At higher temperatures,...

Fracture mechanics A J KINLOCH Basis energy balance and stress-intensity factor approaches... 

TABLE 21.3 Initial Crack Size, Failure Stress, and Stress Intensity Factor JIVE Tanks... 

Wepplemann, E., Swain, M.V., 1996. Investigation of the stresses and stress intensity factors responsible for fracture of thin protective films during ultra-micro indentation tests with spherical indenters. Thin Solid Films 286, 111—121. 

Table 6.3 Fracture energies and stress intensity factors...

Figure 6.27 Fatigue crack propagation rate dependence on cyclic frequency and stress intensity factor range for generic PC.

This is used to calculate the expected defect size at a given time and stress intensity factor. Combining the two equations allows calculation of approximate crack growth rate, i.e the expected crack depth for given values of K and a is calculated by Equation (2.1) for the first year. A new K value (due to the larger defect) is calculated from Equation (1.2) and a new defect size calculated from Equation (2.1). The process is iterated each year until the critical value is reached. 

A method of fracture analysis that can determine the stress (or load) required to induce fracture instabihty in a structure containing a crack-like flaw of known size and shape. See also fracture mechanics and stress-intensity factor. 

Figure 21. Crack velocity v, radius of the Initial curve r, and stress intensity factor Kj In dependence on crack length a at the tip of an extending curvilinear thermal matrix crack in a composite structure.

Dixon, J.R. and Strannigan, J.S., Determination of energy release rates and stress-intensity factors by the finite-element method. J Strain Analysis, 1972, 7, 125-131. 

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