Transverse 45° cracking

However, it is possible that the constant rate of AE activity is interrupted by local peaks of high rate of AE. This is due to the formation of local (internal) delaminations because of interlaminar stresses arising due to the presence of transverse cracks. This is more accentuated in less severe loading conditions. Under severe loading conditions = 80% CTu, R = 0.1) the rate of damage development (delamination growth) is so fast that leads to an overall high rate of AE emission. 

Figure 4 A radiographic image of a welded joint (defect transversal crack), a Original image, b Edge image (only the defect is maintained).

At core B2 a transverse crack going through from the surface down to the duct was found, as well as some weak Fig. 6 Drill core B2 reinforcement bars. Because both the crack and the bars could... 

The electrical-resistance method involves passing an electric current through the structure and exploring the surface with voltage probes. Flaws, cracks, or inclusions will cause a disturbance in the voltage gradient on the surface. Railroads have used this method for many years to locate transverse cracks in rails. 

SCC has been defined as failure by cracking under the combined action of corrosion and stress (Fig. 9.1). The stress and corrosion components interact S3mergistically to produce cracks, which initiate on the surface exposed to the corrodent and propagate in response to the stress state. They may run in any direction but are always perpendicular to the principal stress. Longitudinal or transverse crack orientations in tubes are common (Figs. 9.2 and 9.3). Occasionally, both longitudinal and transverse cracks are present on the same tube (Fig. 9.4). Less frequently, SCC is a secondary result of another primary corrosion mode. In such cases, the cracking, rather than the primary corrosion, may be the actual cause of failure (Fig. 9.5). 

Figure 9.12 Discontinuous, transverse cracks close examination of the photograph will disclose at least five tight, secondary cracks.

Figure 9.22 Transverse cracks originating on the external surface.

Transverse cracks shown in Fig. 10.8 were found in a total of 15 tubes from random areas of the condenser. The equipment had been in continuous service for 2 years. Cracks had not been observed previously. 

Quer-profil, n. cross section, -richtung,/. transverse direction, -riss, m. transverse crack, cross crack cross section Min.) fracture, -schlag, m. Mining) crosscut. 

Check slip areas for longitudinal and transverse cracks and sharp notches. Check tool Joints for wear, galls, nicks, washes, fins, fatigue cracks at root of threads, or other items that would affect the pressure holding capacity or stability of the Joint. 

Due to the complex mixed-mode nature of composite delamination, no closed form solutions have been developed yet to express the influence of governing parameters that control the edge delamination behavior. Under tensile loading, delamination is normally preceded by a number of transverse cracks, particularly in the 90° plies. Because of the presence of these cracks, the location of delamination is not unique as in the case of compressive loading, which invariably results in gross buckling of the laminate. The path of delamination along the axial direction varies... 

The implication of Eq. (6.21) is that the criterion is dependent mainly on the ratio of the energies for longitudinal splitting and transverse cracking, and is relatively insensitive to crack length and the elastic modulus. It is also noted from experimental study that crack speed has a pronounced effect on the toughness ratio, Rl/Ri, and thus the crack deflection phenomenon. 

One of the most important properties which control the damage tolerance under impact loading and the CAI is the failure strain of the matrix resin (see Fig. 8.8). The matrix failure strain influences the critical transverse strain level at which transverse cracks initiate in shear mode under impact loading, and the resistance to further delamination in predominantly opening mode under subsequent compressive loading (Hirschbuehler, 1987 Evans and Masters, 1987 Masters, 1987a, b Recker et al., 1990). The CAI of near quasi-isotropic composite laminates which are reinforced with AS-4 carbon fibers of volume fractions in the range of 65-69% has... 

Place an interleaf immediately below the surface layer if the delamination induced by the transverse cracks originating from the impact surface is to be arrested. 

Altus, E. and Ishai, O. (1990). The effect of soft interleaved layers on the combined transverse cracking/ delamination mechanisms in composite laminates. Composites Sci. Technoi. 39, 13-27. 

Lee S.M. (1984). Correlation between resin material variables and transverse cracking in composites.. /. 

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