Edge cracks

Edge cracking is caused by insufficient pavement support owing to one or more of the following reasons poor compaction, shrinkage, poor drainage or frost action of surrounding/ 

The crack width may vary from a few millimetres up to 50 mm or more. 

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The condition for propagation of a mode 1 edge crack, that is, a crack that is subjected to pure opening (tensile) stresses appHed perpendicular to the crack plane, is given by (35) ... 

In order to apply the crack nucleation approach, the mechanical state of the material must be quantified at each point by a suitable parameter. Traditional parameters have included, for example, the maximum principal stress or strain, or the strain energy density. Maximum principal strain and stress reflect that cracks in rubber often initiate on a plane normal to the loading direction. Strain energy density has sometimes been applied as a parameter for crack nucleation due to its connection to fracture mechanics for the case of edge-cracked strips under simple tension loading. ... 

Fracture Properties of Candidate Metals. Recall that the opening mode stress intensity factor for the case of a component containing a single edge crack in tension, Ki, is given by Eq. (5.47), where Y = 1.12 for the geometry under consideration here ... 

Application of surface size to paper carries with it the transfer of a substantial quantity of water. As an example, surface sizing of a 75g/m2 (501b/3300fit2) sheet (with 1% residual water content) by a 5% starch solution for a coat weight of 1.5 g/m2 (1 lb/3300ft2/side) will raise the water content of the sheet to 43%. This large quantity of water will weaken the paper. Web breaks at the size press can occur, particularly when the sheet is also weakened as a result of edge cracks or holes. 

Double torsion Single-edge cracked plate... 

Ti-5A1 alloy plates reduces rolling edge cracks significantly. Addition of Y2O3 results in affecting grain refinement and thus improved superplastic formability. 

Changes in modulus also affect fracture behaviour. The relaticmship between the two is most clearly seen in the case of brittle fracture. For a wide, thick plate containing an edge crack of length a, the critical applied stress at fracture Oc is related to the Young s modulus , the Poisson s ratio v, and the fracture surface energy Gjc of the material by the Griffith equation ... 

Situation C Edges, cracks, etc. (b) could place at disposal energy richer reaction centres than the surfaces with the normal number of free valencies (a). Therefore, the active centres can be distributed more in case of fractal surface (b) than the non-fractal surface... 

Figures 4 and 5 show the strain energy release rate for a T-shaped crack and symmetric edge cracks, respectively. In these examples the substrate is Rene 41 (E = 219.7 Gpa,...

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