Crack arrestor

Romualdi and Batson (1963) have shown that the tensile strength of FRC at the proportional limit is higher than that of the unreinforced matrix. Closely spaced fibres act as crack arrestors and reduce the stress intensity. In other words, the strength is related to the spacing between the fibres, as shown in Fig. 15.2. The average fibre spacing is calculated from Eq. [15.1] ... 

Due to the crack nature of the defect and to prevent expansion/bulging and failure of the pipe on either side of the leak repair clamp, it was recommended to install within 1 m on either side of the clamp 12-in. crack arrestors. This will not prevent the pipe from continuing to crack, but if it does it will prevent rupture. It is very important that this region of the pipe is restrained as it will greatly help the complete function of the total repair (Lesmana, 2011) (Figure 6.20). 

The ease of installation makes the composite sleeve crack arrestor system effective. These units can be installed on the pipeline without the need to cut the pipe or for any... 

Lesmana, D.S., September 2011. Stopped in it s track — crack arrestor installation in Indonesia. World Pipeline Magazine (Edition), http //www.energyglobal.com/magazines/issue.aspx seo=world-pipelines month=9 year=2011. 

Weaker bond between fibre and matrix is a fracture arrestor, which has been explained by Cook and Gordon hypothesis [58]. In the stress field the tensile component (aj shows a maximum value at some distance before the craek tip (Fig 6.22). A weaker bond in the interfacial plane is broken under this stress before the propagating crack approaches and cross this plane. At this point the crack propagation is ended, which can eventually change a direction of 90 ... 

Are oxygen and acetylene cylinders, gauges, regulators, flashback arrestors, hoses and torches in good condition and free Ifom damage or contamination, e.g. oil, grease, cuts, cracks or any other surface defects ... 

A number of systems investigated as possible carbon fiber sizes are given in Table 9.8. Dauksys [24] attempted to apply a size to form a microductile region adjacent to the interface, which could act as a stress relief medium, a crack inhibitor/arrestor and also attempt to increase the effective transfer length of the fractured fibers. Dauksys, at best, applied a 0.9 /w solution of polyhydroxyether in Cellusolve to Thornel 50 carbon fiber (with the PVA size removed) and from composites prepared from Union Carbide ERL2256 resin,... 

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