Strain energy release rates and the fatigue growth of matrix cracks in model arrays in composite laminates

1991 ◽  
Vol 432 (1886) ◽  
pp. 427-444 ◽  
Keyword(s):  
Energy Release Rate ◽  
Energy Release ◽  
Crack Growth ◽  
Release Rate ◽  
Composite Laminates ◽  
Strain Energy ◽  
Strain Energy Release Rate ◽  
Strain Energy Release ◽  
Matrix Cracks ◽  
Energy Release Rates

Crack growth in the transverse plies of cross-ply composite laminates has been investigated both experimentally and theoretically. Expressions for the strain energy release rate associated with the growth of cracks in model arrays have been obtained using both the compliance approach and the energy method. Measurements of compliance change with crack length were obtained using glass-epoxy laminates and compared with various predictions. Correlations between the crack growth rate and the strain energy release rate range indicate that a Paris law is applicable.

Subcritical crack growth along epoxy/glass interfaces

1992 ◽  
Vol 7 (9) ◽  
pp. 2621-2629 ◽  
Author(s):  
K.M. Conley ◽  
J.E. Ritter ◽  
T.J. Lardner
Keyword(s):  
Energy Release Rate ◽  
Energy Release ◽  
Crack Growth ◽  
Power Law ◽  
Release Rate ◽  
Strain Energy ◽  
Crack Velocity ◽  
Subcritical Crack Growth ◽  
Strain Energy Release Rate ◽  
Strain Energy Release

Subcritical crack growth behavior along polymer/glass interfaces was measured for various epoxy adhesives at different relative humidities. A four-point flexure apparatus coupled with an inverted microscope allowed for observation in situ of the subcritical crack growth at the polymer/glass interface. The specimens consisted of soda-lime glass plates bonded together with epoxy acrylate, epoxy (Devcon), or epoxy (Shell) adhesives. Above a threshold strain energy release rate, the subcritical crack velocity was dependent on the strain energy release rate via a power law relationship where the exponent was independent of the adhesive tested and the test humidity (n = 3). However, the multiplicative constant A in the power law relation varied by over three orders of magnitude between the various adhesives with epoxy (Shell) having the smallest value and the epoxy (Devcon) the greatest value; in addition, A was very sensitive to humidity, decreasing by over two orders of magnitude from 80% to 15% relative humidity. At high strain energy release rates, the subcritical crack velocity reached a plateau at approximately 10−6 m/s. The use of this subcritical crack velocity data in predicting thin film delamination is discussed.

Typical Calculation Method of Stress Intensity Factors and Crack Growth Criterions on Infinite Plate Containing Hole-Edge Cracks

2012 ◽  
Vol 568 ◽  
pp. 154-158 ◽  
Author(s):  
Jin Fang Zhao ◽  
Qun Zhao
Keyword(s):  
Energy Release Rate ◽  
Energy Release ◽  
Crack Growth ◽  
Release Rate ◽  
Integral Method ◽  
Strain Energy ◽  
Strain Energy Release Rate ◽  
Strain Energy Release ◽  
Maximum Strain ◽  
Hole Edge

This paper introduces a finite element analysis software FRANC2D/L to calculate the stress intensity factor (SIF) and simulate the crack growth. Samples with infinite plate containing center crack, one hole-edge crack and two symmetrical hole-edge cracks were analyzed by this software. Comparing the SIF calculation results of the three samples based on displacement correlation method, J-integral method and virtual crack closure integral method, the results show that the three methods are all suitable for calculating the SIF problems, and the calculation precision of J-integral method and virtual crack closure integral method are better. Comparing the three crack growth criterion of maximum circumferential stress, maximum strain energy release rate and minimum strain energy density, the calculation velocity and precision of maximum circumferential stress criterion and minimum strain energy density criterion are prior to maximum strain energy release rate criterion. The calculating time and angle error of maximum strain energy release rate criterion is larger than that of the other two criterions．

Strain-energy release rate for a single-edge-cracked circular bar in tension

1978 ◽  
Vol 13 (2) ◽  
pp. 83-89 ◽  
Author(s):  
O E K Daoud ◽  
D J Cartwright ◽  
M Carney
Keyword(s):  
Energy Release Rate ◽  
Energy Release ◽  
Release Rate ◽  
Strain Energy ◽  
Strain Energy Release Rate ◽  
Circular Cross Section ◽  
Strain Energy Release ◽  
Energy Release Rates ◽  
Circular Bar ◽  
Strain Energy Release Rates

The strain-energy release rate is determined for an edge crack in a uniformly stressed bar of circular cross-section. Values of the strain-energy release rate, obtained using a finite-element representation of the bar and by measuring the compliance of the bar experimentally, are shown to be in close agreement. For crack depths of less than one-half diameter, the strain-energy release rates are found to be lower than existing results on rectangular bars having the same relative crack length.

Developing Failure Criteria for Adhesive Joints Under Complex Loading

1978 ◽  
Vol 100 (1) ◽  
pp. 25-31 ◽  
Author(s):  
D. R. Mulville ◽  
D. L. Hunston ◽  
P. W. Mast
Keyword(s):  
Energy Release Rate ◽  
Energy Release ◽  
Crack Growth ◽  
Release Rate ◽  
Strain Energy ◽  
Strain Energy Release Rate ◽  
Strain Energy Release ◽  
Failure Criteria ◽  
Failure Behavior ◽  
Wide Range

This paper describes an investigation of the failure behavior of bonded joints under a wide range of in-plane loading. Combinations of tension, shear, and bending loads were applied to bonded joint specimens using a unique computer-controlled loading system. Failure criteria were developed for initiation of crack growth or the onset of nonlinear behavior based on a computation of energy dissipated by the failure process. Failure surfaces were constructed from these data for the range of loadings studied. A strain energy release rate formulation was developed for bonded materials which fail under shear, tension, and bending loading by interfacial crack growth. This formulation was used to analyze specimens which failed by debonding along the interface. Results of these studies were also compared with failure criteria obtained using a larger scale specimen on the basis of strain energy release rate.

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