Study on Fatigue Crack Growth Model of Attachment Lug Subjected to Oblique Pin-Load

The finite element model of a straight attachment lug subjected to an oblique loading less than 45 degrees is built by using the finite element software ANSYS, a cosine pin-bearing pressure distribution is applied on the hole of lug as a boundary condition. The stress intensity factor (SIF) expression for the straight attachment lug with a single through-the-thickness crack, which is subjected an oblique pin-load less than 45 degrees, is determined by studying on the influence law of dimensionless crack length (a/R1)，ratio of outer radius to inside radius (R2/R1), inside radius (R1) and pin-load angle (β) on the SIFs values. The expression is validated by contrasting with the ANSYS results and the data of residual strength test. The stress intensity factor’s amplitude (ΔK) are calculated by the SIF equation to get the values of the Paris constants. The fatigue crack growth model of attachment lug subjected to oblique pin-load is established, offering an analytical as well as experimental method for assessing and designing damage tolerant attachment lugs.

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Study on Fatigue Crack Growth Model of 7075-T7410 Aluminum Alloy Straight Attachment Lug

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.66-68.82 ◽

2011 ◽

Vol 66-68 ◽

pp. 82-89

Author(s):

Li Ming Wu ◽

Yu Ting He ◽

Xin Bo Wang ◽

Hai Wei Zhang ◽

Jin Qiang Du ◽

...

Keyword(s):

Finite Element ◽

Fatigue Crack ◽

Stress Intensity ◽

Fatigue Crack Growth ◽

Crack Growth ◽

Growth Model ◽

Outer Radius ◽

Finite Element Software ◽

Inside Radius ◽

Crack Growth Model

The finite element model of a 7075-T7410 straight attachment lug is built by using the finite element software ANSYS, a cosine distribution pin-bearing pressure is applied on the surface of the pin-hole as a boundary condition. The stress intensity factor (SIF) expression for the straight attachment lug with a single through-the-thickness crack and subjected to an axial pin-load is determined by studying on the effect of the geometric parameters (the dimensionless crack length a/R1，the ratio of outer radius to inside radius R2/R1 and the inside radius R1) on SIF value. The fatigue crack growth velocity (da-dN) and the stress intensity factor’s amplitude (ΔK) is calculated by the SIFs equations to get the values of the Paris constants, offering an analytical method for establishment of the fatigue crack growth model of the typical straight lugs. The paper can be helpful in assessing and designing damage tolerant attachment lugs.

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A fatigue crack growth model based on the contact stress intensity factor approach

Theoretical and Applied Fracture Mechanics ◽

10.1016/0167-8442(89)90032-3 ◽

1989 ◽

Vol 12 (2) ◽

pp. 149-154 ◽

Cited By ~ 5

Author(s):

Y.C. Lam

Keyword(s):

Stress Intensity Factor ◽

Fatigue Crack ◽

Stress Intensity ◽

Fatigue Crack Growth ◽

Intensity Factor ◽

Crack Growth ◽

Growth Model ◽

Contact Stress ◽

Model Based ◽

Crack Growth Model

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Crack Growth Model for the Probabilistic Assessment of Inspection Strategies for Steam Generator Tubes

Volume 1: Plant Operations, Maintenance, Engineering, Modifications and Life Cycle; Component Reliability and Materials Issues; Next Generation Systems ◽

10.1115/icone17-75618 ◽

2009 ◽

Author(s):

Brian Wolf ◽

Shripad T. Revankar ◽

Jovica R. Riznic

Keyword(s):

Stress Intensity Factor ◽

Fatigue Crack ◽

Stress Intensity ◽

Fatigue Crack Growth ◽

Crack Growth ◽

Steam Generator ◽

Growth Model ◽

Region I ◽

Crack Growth Model ◽

Region Ii

Assessment of the conditional probabilities of tube failures, leak rates, and ultimately risk of exceeding licensing dose limits as an approach used to steam generator tube fitness-for-service assessment has begun to be used increasingly in recent years throughout the nuclear power industry. One of the important topics in the assessment is the crack growth model that predicts the growth of crack size with time. The plot of the log of change in crack length per cycle, against the log of stress intensity factor range shows three distinct regions where in Regions I and III the change in crack length per cycle increases faster with stress intensity factor. On the other hand Region II shows linear variation. While effective for predicting Region II of fatigue crack growth, “Paris law” is often not properly used in making life predictions because a majority of the fatigue life of a specimen occurs in Region I. Physical models for Region I growth have not yet been successful. Recently substantial effort is made in modeling crack growth model with experimental data for Regions I and II. The present work reviews recent work in predicting the fatigue crack growth rate in Region I and II. The characteristics of such models are examined and their limitations are discussed in context with steam generator tube crack growth. Recommendations are made on crack growth models for region I and II.

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