Fracture Analysis of Notched Composites

1987 ◽  
Vol 109 (1) ◽  
pp. 27-35 ◽  
Author(s):  
F. Delale
Keyword(s):  
Stress Concentration ◽  
Crack Opening Displacement ◽  
Composite Laminate ◽  
Orthotropic Plate ◽  
Crack Opening ◽  
Crack Problem ◽  
Fracture Analysis ◽  
Opening Displacement ◽  
Concentration Factors ◽  
Stress Concentration Factors

In this study the problem of part-through cracks emanating from a central notch in a composite laminate is considered. The composite laminate is modeled as an orthotropic plate and along the branches, it is assumed that the stresses are carried by the fibers only. The stresses along the uncracked portions are assumed to be proportional to the crack opening displacement at that point. After formulating the branched crack problem, the model is applied to a (±45 deg)2s composite laminate. The stress concentration factors for the fibers are computed for various values of the spring constant K. Sample results showing the crack opening displacement are also displayed in the figures.

A NEW METHOD TO DETERMINE TENSILE-STRAIN SOFTENING CURVE OF QUASI-BRITTLE MATERIALS

2014 ◽  
Vol 1 (1) ◽  
Author(s):  
Ruimei An ◽  
Shujin Duan ◽  
Quanmin Guo
Keyword(s):  
Crack Opening Displacement ◽  
Tensile Strain ◽  
Strain Softening ◽  
Crack Opening ◽  
Crack Problem ◽  
Brittle Materials ◽  
Cohesive Crack ◽  
New Method ◽  
Opening Displacement ◽  
Softening Curve

Based on weight integration to obtain a closed solution of cohesive crack problem, a new method is proposed to determine the tensile-strain softening curve (TSC) for quasi-brittle materials. The key technique is to determine the weight function by superposition of the solution with different fictitious crack lengths to satisfy a given crack opening displacement within cohesive crack surfaces. As an example, a central crack problem under uniform tension with given crack opening displacement in the fracture process zone (FPZ) was analyzed, the corresponding TSC was determined, and then the solution for stress and displacement field was obtained.

The Effect of Adhesive Layers on the Fracture of Laminated Structures

1978 ◽  
Vol 100 (1) ◽  
pp. 2-9 ◽  
Author(s):  
M. R. Gecit ◽  
F. Erdogan
Keyword(s):  
Stress Intensity ◽  
Stress Concentration ◽  
Plane Stress ◽  
Crack Problem ◽  
Adhesive Layer ◽  
Elastic Continuum ◽  
Adhesive Layers ◽  
Concentration Factors ◽  
Stress Concentration Factors ◽  
Laminated Structures

In this paper the effect of the thickness and the elastic properties of the adhesive layers in laminated structures is considered. The structure is assumed to consist of two sets of periodically arranged dissimilar layers which may contain cracks perpendicular to the interfaces. The crack problem is solved under the assumption of plane strain or generalized plane stress and by using two different models for the adhesive layers. In the first model the adhesive layer is approximated by a combination of tensile and shear springs. In the second the adhesive layer is considered to be an elastic continuum, hence involving no approximating assumptions. The results regarding the stress intensity and stress concentration factors obtained from these two models and that found by ignoring the adhesive layers are presented and some comparisons are made.

Stress concentration factors of edge-notched orthotropic plates

1998 ◽  
Vol 33 (5) ◽  
pp. 395-398 ◽  
Author(s):  
C R Chiang
Keyword(s):  
Stress Concentration ◽  
Material Properties ◽  
Shape Factor ◽  
Isotropic Material ◽  
Simple Formula ◽  
Orthotropic Plate ◽  
Orthotropic Plates ◽  
Concentration Factors ◽  
Stress Concentration Factors ◽  
Material Factor

For an edge-notched semi-infinite orthotropic plate, the stress concentration factor has been shown to be 1 + FmFs, where Fm and Fs are material factor and shape factor respectively. Since Fs is independent of material properties, a simple formula for Fs is proposed by interpolating two theoretical values of the isotropic material. The accuracy of the formula is assured by finding that its predictions are in excellent agreement with available solutions. An example of the computation of the stress concentration factors of edge-notched orthotropic plates is presented to illustrate its simplicity and accuracy.

scholarly journals Stress Concentration Factors for Welded Plate T-Joints Subjected to Tensile, Bending and Shearing Loads

Materials ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 546
Author(s):  
Krzysztof L. Molski ◽  
Piotr Tarasiuk
Keyword(s):  
Stress Concentration ◽  
Plate Thickness ◽  
Percentage Error ◽  
Geometrical Parameters ◽  
T Joints ◽  
Loading Mode ◽  
Weld Toe ◽  
Concentration Factors ◽  
Parametric Expression ◽  
Stress Concentration Factors

The paper deals with the problem of stress concentration at the weld toe of a plate T-joint subjected to axial, bending, and shearing loading modes. Theoretical stress concentration factors were obtained from numerical simulations using the finite element method for several thousand geometrical cases, where five of the most important geometrical parameters of the joint were considered to be independent variables. For each loading mode—axial, bending, and shearing—highly accurate closed form parametric expression has been derived with a maximum percentage error lower than 2% with respect to the numerical values. Validity of each approximating formula covers the range of dimensional proportions of welded plate T-joints used in engineering applications. Two limiting cases are also included in the solutions—when the weld toe radius tends to zero and the main plate thickness becomes infinite.

Fatigue Crack Growth Tests on Glass Fibre Reinforced Polymer Matrix Composite

2005 ◽  
Vol 473-474 ◽  
pp. 189-194
Author(s):  
Zilia Csomós ◽  
János Lukács
Keyword(s):  
Cyclic Loading ◽  
Crack Opening Displacement ◽  
Matrix Composite ◽  
Glass Fibre ◽  
Crack Opening ◽  
Loading Conditions ◽  
Opening Displacement ◽  
Interfacial Cracks ◽  
Glass Fibre Reinforced ◽  
Number Of Cycles

E-glass fibre reinforced polyester matrix composite was investigated, which was made by pullwinding process. Round three point bending (RTPB) specimens were tested under quasi-static and mode I cyclic loading conditions. Load vs. displacement (F-f), load vs. crack opening displacement (F-v) and crack opening displacement range vs. number of cycles (ΔCOD-N) curves were registered and analysed. Interfacial cracks were caused the final longitudinal fracture of the specimens under quasi-static and cyclic loading conditions.

Stress Analysis of Holes in Thick Plates

2004 ◽  
Vol 1-2 ◽  
pp. 153-158 ◽  
Author(s):  
S. Quinn ◽  
Janice M. Dulieu-Barton
Keyword(s):  
Stress Concentration ◽  
Stress Analysis ◽  
Uniaxial Tension ◽  
Plane Stress ◽  
Plate Surface ◽  
Flat Plates ◽  
Thick Plates ◽  
Concentration Factors ◽  
Stress Concentration Factors

A review of the Stress Concentration Factors (SCFs) obtained from normal and oblique holes in thick flat plates loaded in uniaxial tension has been conducted. The review focuses on values from the plate surface and discusses the ramifications of making a plane stress assumption.

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