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Development of non-destructive quality assessment criterion of 7075-T6 Al-Zn-Mg alloy components using fracture mechanics techniques

✍ Scribed by K.L. Barui; B. Bhattacharya


Book ID
103073371
Publisher
Elsevier Science
Year
1994
Tongue
English
Weight
769 KB
Volume
47
Category
Article
ISSN
0013-7944

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✦ Synopsis


Ahatraet-A quality assessment procedure based on a fracture mechanics approach is analytically developed for the nondestructive evaluation of components made of 7075-T6 grade Al-zn-Mg alloy. The maximum allowable defect sires for both static and cyclic loads are computed. For d&rent stress levels and shapes of the defects, the initially existing allowable defect sizes versus number of operating cycles curves are presented. The tolerable defect sizes, in most of the cases, are found to be well below the detectable limit of the most sensitive nondestructive testing techniques. Hence knowledge of the maximum allowable operating cycles of the components for non-destructively detectable minimum defects is essential. A practical example of the assessment of welded aluminium alloy bridge components is cited. These assessments are very helpful in the realistic prediction of the safe life of the components as well as their best utilization in service. dd/dN E(K) F 4 9 4c N NOMENCLATURE flaw depth, critical flaw depth, initial flaw depth for surface flaw (half of the flaw depth, critical flaw depth, initial flaw depth for internal flaw) crack growth constants half of the flaw length crack growth rate flaw shape parameter boundary correction factor stress intensity factor, critical stress intensity factor number of cycles depth correction factor due to plastic zone thickness of the component for surface flaw (half of the thickness for internal flaw) half of the width of the component range of applied stress, yield stress parametric angle of the ellipse