Evaluation of surface energy for formation of multiple edge cracks using Medg-integral

A novel contour integral approach termed Medg is introduced for computation of the surface energy required for the formation of multiple edge cracks. The method is developed by reinterpretation of the conventional M-integral with deliberate delimitation of integration contour and selection of coordinate origin. Due to path independence, this method is efficient, easy to implement by using finite elements, and does not require a complicated mesh around the crack tips for good accuracy. Attention is also addressed to discussion of the size effects on proper interpretation of its physical meaning. The adequacy of the numerical results computed for the finite size corrections has been validated by using some of the available empirical formulations. It is observed that the size effect can be neglected when the crack size remains under one-tenth of the structure size. The results of a specific multi-cracked geotechnical structure suggest that, the damage state such as degradation of the structural stiffness due to the presence of edge cracks can be properly inspected by using Medg.

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Fatigue Life Appraisal and Its Corrected Stress Intensity Factor for Repaired Off-CentrallyCracked Aluminum Plates

Materials ◽

10.3390/ma13184014 ◽

2020 ◽

Vol 13 (18) ◽

pp. 4014

Author(s):

Xiang You ◽

Zhiyu Wang ◽

Xiafang Zhou ◽

Zifeng Liu ◽

Ruijuan Jiang ◽

...

Keyword(s):

Fatigue Life ◽

Element Model ◽

Crack Size ◽

Plate Edge ◽

Life Estimation ◽

Fatigue Life Estimation ◽

Life Improvement ◽

Edge Cracks ◽

Aluminum Plates ◽

Sensitive Parameters

This paper presents an experimental study on the fatigue life estimation of off-centrally cracked aluminum plates. Typical theoretical equations for off-central, central and edge cracks were reviewed and compared in terms of their sensitive parameters and applicability. A finite element model has been validated in its capacity in modelling the influences of eccentricity and crack size on the boundary correction coefficients. The Forman equation has been employed along with numerical results for the prediction of fatigue lives. Based on the test data, the fatigue life results of aluminum plates with and without patched laminate repair have been compared with codified fatigue classes. It is demonstrated that the repair at the crack tip close to the plate edge is effective in the fatigue life improvement for off-centrally crackedaluminum plates.

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Stress Intensity Factors of Double and Multiple Edge Cracks

JSME international journal Ser A Mechanics and material engineering ◽

10.1299/jsmea1993.40.1_1 ◽

1997 ◽

Vol 40 (1) ◽

pp. 1-7

Author(s):

Nao-Aki NODA ◽

Motoki TSURU ◽

Kazuhiro ODA

Keyword(s):

Stress Intensity ◽

Stress Intensity Factors ◽

Multiple Edge ◽

Intensity Factors ◽

Edge Cracks

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Solution of Multiple Edge Cracks in an Elastic Half Plane

International Journal of Fracture ◽

10.1007/s10704-005-3063-3 ◽

2006 ◽

Vol 137 (1-4) ◽

pp. 121-137 ◽

Cited By ~ 22

Author(s):

Xiaoqing Jin ◽

Leon M. Keer

Keyword(s):

Half Plane ◽

Multiple Edge ◽

Edge Cracks

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Second-order flexibility-based model for nonlinear inelastic analysis of composite steel-concrete frameworks with partial composite action and semi-rigid connections

Proceedings 12th international conference on Advances in Steel-Concrete Composite Structures - ASCCS 2018 ◽

10.4995/asccs2018.2018.7213 ◽

2018 ◽

Author(s):

Cosmin G Chiorean ◽

Marius S Buru

Keyword(s):

Concrete Slab ◽

Finite Size ◽

Composite Beams ◽

Second Order ◽

Integral Approach ◽

Cross Sectional ◽

Composite Action ◽

Inelastic Analysis ◽

The Cross ◽

Composite Steel

This paper presents an efficient computer method for large deflection distributed plasticity analysis of 3D semi-rigid composite steel-concrete frameworks. A novel second-order inelastic flexibility-based element has been developed by combining the Maxwell-Mohr rule and the second-order force based functions for computation of the generalized displacements. The proposed model allows explicit and efficient modeling of the combined effects of nonlinear geometrical effects, gradual spread-of-plasticity, partial shear connection of composite beams, finite-size joints and joint flexibility by using only one 2-noded beam-column element per physical member. For composite beams, based on elasto-plastic cross-sectional analyses the model is able to take into account the effects of partial composite action between the concrete slab and the steel beam. At the cross-sectional level the proposed method addresses computational efficiency through the use of path integral approach to numerical integration of the cross-sectional nonlinear characteristics and residual stresses, enabling in this way the accurate geometrical specifications and precise modeling of cross-sections. The proposed nonlinear analysis formulation has been implemented in a general nonlinear static purpose computer program, NEFCAD. Several computational examples are given to validate the accuracy and efficiency of the proposed method.

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Validation of a Composite Strength Prediction Methodology Based on Critical Failure Volume

Design Engineering and Computers and Information in Engineering, Parts A and B ◽

10.1115/imece2006-14976 ◽

2006 ◽

Author(s):

Endel V. Iarve ◽

David H. Mollenhauer ◽

Thomas J. Whitney

Keyword(s):

Material Property ◽

Finite Size ◽

Integral Approach ◽

Strength Prediction ◽

Material Strength ◽

Fiber Direction ◽

Stress Concentrations ◽

Average Strength ◽

Additional Material ◽

Direct Evaluation

The strength prediction of composites with stress concentrations is concerned with material response in small highly stressed volumes. Direct evaluation of material strength in such areas is difficult to achieve in practice. On the other hand, the ability of such small regions to sustain loads exceeding the average strength measured on uniformly loaded coupons, e.g. ASTM standard for axial strength testing in unidirectional composites, is the foundation of the long standing Whitney-Nuismer point and average stress failure criteria. These criteria postulate that the failure of a composite with stress concentrations occurs when a finite size volume near the stress concentration is loaded at or above the average strength measured on standard test coupons without stress concentrators. The size of this volume constitutes an additional material property. While proving accurate and efficient for capturing the notch size effect on strength within a given laminate family, these dimensions have not found clear physical interpretation and appear not to represent a fundamental material property. The present paper reports results for a Weibull-based integral approach for composite laminates with open holes. The emphasis is on evaluation of the limits of the applicability of the traditional Weibull integral based fiber-direction strength scaling.

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