Ductile tearing

Fig. 8.3 Schematic representation of the stress corrosion cracking mechanism of the pit (after Pickering and Swann ). (a) Tubular pits initiated at solute-rich slip step. The pits may, but need not necessarily, follow the slip plane once they are initiated, (b) Ductile tearing along a plane containing the tubular pits. The stress is increased across the plane because of the reduced cross section and the stress raising effect...

Many studies [40-43] have been performed on the fracture behaviour of PMMA as a function of temperature or cross-head speed. As an illustration, Fig. 30 shows the critical stress intensity factor, K c, in a log-log plot as a function of temperature for various crack speeds [40]. The temperature range is limited to + 80 °C in order to avoid ductile tearing. In the stable crack growth regime of interest here, whatever the crack speed, K c decreases with increasing temperature. 

Landes and has since received wide attention. As yet, there are no published papers describing the direct measurement of. rubber-tou ened plastics or other particulate composites. Williams and co-workers have attempted to estimate Jjc for HIPS and ABS indirectly, from the work done at the crack tip in SEN specimens sulqected to tenaon or bending As the fracture surfaces were extensively whitened, these estimates were probably hi the 7/ criterion should strictly be applied to the point of crack initiation rather tiian to later stages of ductile tearing. 

The fracture surface of the dispersed particles was different from that of the epoxy phase. The particles fractured in a ductile manner and the adhesion between the dispersed phase and matrix was good. Thus, the dispersed phase could slow down the propagation of the crack by the ductile tearing of the particles. The thickness of... 

The welded joint fractured in the same manner as the base metal, e.g., a ductile-tearing type of fracture was observed after general yielding, with no evidence of instability. Also, the fracture strength and its temperature dependence were nearly equal to that of the base metal. 

VI.4. The first method is included to cover the approach which seeks to ensure that, whatever the loading conditions required to cause failure, such a failure will always involve extensive plasticity and/or ductile tearing, and unstable brittle fracture will not occur in any circumstances. The second is addressed to provide consistency with the generally accepted practice for evaluating ferritic steels. The third provides a method for evaluating brittle fracture that is suitable for a wide range of materials. It... 

Many of the properties of a rubber can be significantly altered by incorporation of a filler these include cure rate, tensile properties (strength, modulus, ductility), tear strength, hysteresis and resistance to permanent set, abrasion resistance, swelling behaviour in various fluids, density and, of course, cost. 

Brittle fracture in proximal end of failed catheter with ductile tear lower at left. 

When the surface is put into tension (by bending, or by the application of a tensile test) cracks form readily in the embrittled layer and often propagate into the interior, leading to failure (Figure 1). Even though the interior may be relatively undegraded chemically, a crack in the embrittled layer may provide sufficient stress concentration to cause brittle fracture or a ductile tearing failure instead of deformation and draw-ing. 

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