Stress-Intensity Factors and Complex Path-Independent Integrals

1980 ◽  
Vol 47 (2) ◽  
pp. 342-346 ◽  
Author(s):  
P. S. Theocaris ◽  
N. I. Ioakimidis
Keyword(s):  
Stress Intensity ◽  
Stress Intensity Factors ◽  
Complex Analysis ◽  
Complex Stress ◽  
Complex Potentials ◽  
Intensity Factors ◽  
Antiplane Elasticity ◽  
Elasticity Problems ◽  
Crack Tips

Path-independent integrals about crack tips may be used to estimate stress-intensity factors at crack tips in plane and antiplane elasticity problems. In this paper a new class of such integrals is established by using complex stress functions and the trivial application of the Cauchy theorem of complex analysis. Both the simple Westergaard complex potentials of plane and antiplane elasticity and the more general Muskhelishvili complex potentials will be used for the construction of appropriate path-independent integrals. Two applications of these integrals to the theoretical determination of stress-intensity factors at crack tips are presented. An optical method for the experimental determination of stress-intensity factors at crack tips, based on the use of appropriate complex path-independent integrals, is also proposed.

Complex Stress Intensity Factors in Bent Plates With Cracks

1982 ◽  
Vol 49 (1) ◽  
pp. 87-96 ◽  
Author(s):  
P. S. Theocaris
Keyword(s):  
Stress Intensity ◽  
Stress Intensity Factors ◽  
Complex Stress ◽  
Intensity Factors ◽  
Simple Method ◽  
Cracked Plates ◽  
Crack Tips ◽  
Asymmetric Bending ◽  
Bent Plates

The experimental method of caustics was applied to the study of asymmetric bending of isotropic cracked plates and to the determination of the complex stress intensity factors (S.I.F’s) at the crack tips. It was shown that the method of reflected caustics is convenient for detecting and evaluating both KI and KII stress intensity factors. Based on the singular approximation of the elastic solution around the crack tip, the theory of formation of the caustics was developed and related to the evaluation of both components of stress intensity factors. It was also shown that the generalized method of caustics, known as the method of pseudocaustics, is a potential and simple method for determining S.I.F’s in cracked plates submitted to bending. Experimental evidence with specimens made either of optically inert materials, such as plexiglass, or of any opaque material like steel, and elastically loaded, has corroborated the theoretical results.

DETERMINATION OF RESIDUAL STRESSES AND STRESS INTENSITY FACTORS BY REMOVING LOCAL MATERIAL

2017 ◽  
Vol 48 (4) ◽  
pp. 377-398
Author(s):  
Svyatoslav Igorevich Eleonskii ◽  
Igor Nikolaevich Odintsev ◽  
Vladimir Sergeevich Pisarev ◽  
Stanislav Mikhailovich Usov
Keyword(s):  
Stress Intensity ◽  
Residual Stresses ◽  
Stress Intensity Factors ◽  
Intensity Factors ◽  
Local Material

Experimental Determination of KI for Short Internal Cracks

2001 ◽  
Vol 68 (6) ◽  
pp. 937-943 ◽  
Author(s):  
K. Bearden ◽  
J. W. Dally ◽  
R. J. Sanford
Keyword(s):  
Stress Intensity ◽  
Stress Intensity Factors ◽  
Edge Crack ◽  
Series Solution ◽  
Experimental Studies ◽  
Experimental Methods ◽  
Internal Crack ◽  
Intensity Factors ◽  
Mode Stress

Since the pioneering discussion by Irwin, a significant effort has been devoted to determining stress intensity factors (K) using experimental methods. Techniques have been developed to determine stress intensity factors from photoelastic, strain gage, caustics, and moire´ data. All of these methods apply to a relatively long single-ended-edge crack. To date, the determination of K for internal cracks that are double-ended by experimental methods has not been addressed. This paper describes a photoelastic study of tension panels with both central and eccentric internal cracks. The data recorded in the experiments was analyzed using a new series solution for the opening-mode stress intensity factor for an internal crack. The data was also analyzed using the edge-crack series solution, which is currently employed in experimental studies. Results indicated that the experimental methods usually provided results accurate to within three to five percent if the series solution for the internal crack was employed in an overdeterministic numerical analysis of the data. Comparison of experimental results using the new series for the internal crack and the series for an edge crack showed the superiority of the new series.

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