Comprehensive data for stress intensity factor and critical crack length in chevron notched semi-circular bend specimen subjected to tensile type fracture mode

This paper proposes a way to use finite element models to determine the effect of fatigue cracks in ship structures. Cracks of different lengths are modeled and the maximum nodal stress at the crack tip is used to estimate the stress intensity level. The calculated stress intensity factor is substituted into fracture mechanics equations to calculate the rate of crack growth and the critical crack length. The main advantage to calculating the stress intensity factor from an appropriate finite element model is that load redistribution effects are included. Since the ship structure is redundant, load shedding and multiple load paths can significantly reduce the propagation rate and thereby improve the safety of the structure. Including the crack in the finite element model also makes it possible to study the crack's impact on the stress levels in surrounding structure. The method is independent of the cause of structural failure, hence this kind of analysis can be used to investigate the effects of cracks created by fatigue, collision, or grounding damage.

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Effect of specimen crack lengths on stress intensity factor for Al6061-TiC composites using experimental and 3D numerical methods

International Journal of Structural Integrity ◽

10.1108/ijsi-09-2016-0030 ◽

2017 ◽

Vol 8 (5) ◽

pp. 506-515 ◽

Cited By ~ 1

Author(s):

Raviraj M.S. ◽

Sharanaprabhu C.M. ◽

Mohankumar G.C.

Keyword(s):

Stress Intensity Factor ◽

Finite Element ◽

Stress Intensity ◽

Intensity Factor ◽

Crack Length ◽

Finite Element Simulations ◽

Experimental Results ◽

Crack Mouth Opening Displacement ◽

3D Finite Element ◽

Content Type

Purpose The purpose of this paper is to present the determination of critical stress intensity factor (KC) both by experimental method and three-dimensional (3D) finite element simulations. Design/methodology/approach CT specimens of different compositions of Al6061-TiC composites (3wt%, 5wt% and 7wt% TiC) with variable crack length to width (a/W=0.3-0.6) ratios are machined from as-cast composite block. After fatigue pre-cracking the specimens to a required crack length, experimental load vs crack mouth opening displacement data are plotted to calculate the KC value. Elastic 3D finite element simulations have been conducted for CT specimens of various compositions and a/W ratios to compute KC. The experimental results indicate that the magnitude of KC depends on a/W ratios, and significantly decreases with increase in a/W ratios of the specimen. Findings From 3D finite element simulation, the KC results at the centre of CT specimens for various Al6061-TiC composites and a/W ratios show satisfactory agreement with experimental results compared to the surface. Originality/value The research work contained in this manuscript was conducted during 2015-2016. It is original work except where due reference is made. The authors confirm that the research in their work is original, and that all the data given in the article are real and authentic. If necessary, the paper can be recalled, and errors corrected.

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