Applicability Evaluation of the Weight Function Based Strip Yield Model for an Embedded Crack Problems

2009 ◽  
Author(s):  
Koji Gotoh ◽  
Yukinobu Nagata
Keyword(s):  
Weight Function ◽  
Surface Crack ◽  
Crack Opening ◽  
Yield Model ◽  
Uniform Loading ◽  
Strip Yield Model ◽  
Synthesis Methodology ◽  
Embedded Crack ◽  
Applicability Evaluation ◽  
Perfect Plastic

Applicability evaluation of the developed weight function based strip yield model for an embedded crack by applying the slice synthesis methodology in elastic-perfect plastic bodies under monotonic uniform loading is performed. Although the weight function based strip yield model for a part-through semi-elliptical surface crack in an elastic-perfect plastic bodies under monotonic uniform loading was proposed by Daniewicz and Aveline (2000), applicable geometries of cracked bodies is limited. Their proposed strip yield model treats only a semi-elliptical surface crack in semi-infinite bodies. Besides, quantitative investigations of the applicability seem to be insufficient. The authors proposed the improved strip yield model with slice synthesis methodology for an embedded crack, which enables to treat the finite boundary problems. By applying proposed model, the back surface effect of the crack opening behaviour and the plastic zone growth can be considered. The validity of improved strip yield model for embedded cracks is confirmed by comparing crack opening profiles under some crack geometries with elastic-plastic finite element analyses.

On the determination and application of cod to epoxy-bonded aluminium joints

1979 ◽  
Vol 14 (2) ◽  
pp. 37-42 ◽  
Author(s):  
C L Chow ◽  
C W Woo ◽  
J L Sykes
Keyword(s):  
Crack Opening ◽  
Load Control ◽  
Yield Model ◽  
Cohesive Fracture ◽  
Element Analysis ◽  
Testing Conditions ◽  
Strip Yield Model ◽  
Dimensional Finite Element ◽  
Good Agreement

A method of analysis is presented for the determination of crack-opening-displacements (COD) and their application to aluminium—Araldite joint systems. Use is made of a beam-on-elastic-foundation (BEF) model, which is extended to represent the physical system. It is seen that, in conjunction with this, the Dugdale ‘strip-yield’ model solution may be combined to characterize interfacial or cohesive fracture cases. Fracture toughness values, based on both load and displacement control testing conditions, are examined and show that the equation derived for the load-control model yields greater accuracy. Results of the proposed method are compared with those obtained by a two-dimensional, finite-element analysis and are found to be in good agreement. The validity of the proposed analysis is further verified by experimental observations employing conventional compliance methods for both interfacial and cohesive fracture modes.

Application of the Strip Yield Model to Crack Growth Predictions for Structural Steel

2010 ◽  
Vol 57 (1) ◽  
pp. 1-20
Author(s):  
Małgorzata Skorupa ◽  
Tomasz Machniewicz
Keyword(s):  
Structural Steel ◽  
Crack Growth ◽  
Model Calibration ◽  
Load History ◽  
Yield Model ◽  
Variable Amplitude Loading ◽  
Variable Amplitude ◽  
Constraint Factors ◽  
Strip Yield Model ◽  
Closure Mechanism

Application of the Strip Yield Model to Crack Growth Predictions for Structural SteelA strip yield model implementation by the present authors is applied to predict fatigue crack growth observed in structural steel specimens under various constant and variable amplitude loading conditions. Attention is paid to the model calibration using the constraint factors in view of the dependence of both the crack closure mechanism and the material stress-strain response on the load history. Prediction capabilities of the model are considered in the context of the incompatibility between the crack growth resistance for constant and variable amplitude loading.

Strip Yield Analysis for Multiple Cracked Sheet With Riveted Stiffeners

1993 ◽  
Vol 115 (4) ◽  
pp. 398-403 ◽  
Author(s):  
T. Nishimura
Keyword(s):  
Plastic Zone ◽  
Stress Singularity ◽  
Fredholm Integral Equations ◽  
Multiple Cracks ◽  
Basic Solution ◽  
Yield Model ◽  
Strip Yield Model ◽  
Crack Tips ◽  
Fictitious Crack ◽  
Crack Tip Opening

An elasto-plastic analysis is conducted based upon a strip yield model for analyzing multiple cracks in a sheet reinforced with riveted stiffeners. Using the basic solution of a single crack and taking unknown fictitious surface tractions and fastener forces, Fredholm integral equations are formulated from the equilibrium condition along multiple cracks in the sheet. In addition compatibility equations of displacements are formulated among the sheet, fasteners and stiffeners. Based upon no stress singularity at the fictitious crack tips, these equations are iteratively solved as a single system of equations. Then the unknown fictitious surface tractions, fastener forces, and plastic zone sizes ahead of the crack tips are determined. The crack tip opening displacements for a multiple cracked sheet with riveted stiffeners are determined from the derived fictitious surface tractions and plastic zone sizes. Four example calculations and predictions are presented.

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