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.

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.

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．

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.

Application of Virtual Crack Close Technique in the Static Crack Growth Based on Strain Energy Release Rate Criterion

2012 ◽  
Vol 204-208 ◽  
pp. 3002-3008
Author(s):  
Chen Cheng ◽  
Shui Wan ◽  
Zhen Wen Jang
Keyword(s):  
Energy Release Rate ◽  
Energy Release ◽  
Crack Growth ◽  
Release Rate ◽  
Strain Energy ◽  
Strain Energy Release Rate ◽  
Strain Energy Release ◽  
Element Model ◽  
Energy Release Rate Criterion ◽  
Rate Criterion

A method to simulate the crack growth, according to the strain energy release rate criterion, with the virtual crack close technique, is studied. The virtual crack close technique is used to calculate the strain energy release rate. To achieve the virtual crack close technique, in the FEA software of ANSYS, COMBIN14 spring elements are adopted to set up the finite element model. Then this method to simulate the crack growth is validated by three crack growth problems. This method is a useful and accurate numerical simulation method.

Ultrasonic Lamb Wave Based Crack Growth Prediction for Estimation of Strain Energy Release Rate

2012 ◽  
Vol 585 ◽  
pp. 24-28 ◽  
Author(s):  
Chennamsetti Ramadas ◽  
Avinash Hood ◽  
Krishnan Balasubramaniam ◽  
Makarand Joshi
Keyword(s):  
Energy Release Rate ◽  
Energy Release ◽  
Crack Growth ◽  
Release Rate ◽  
Strain Energy ◽  
Strain Energy Release Rate ◽  
Lamb Waves ◽  
Strain Energy Release ◽  
Low Velocity ◽  
Lamb Mode

A technique is proposed to predict crack growth for the estimation of Strain Energy Release Rate (SERR) of Double Cantilever Beam (DCB) bi-metallic specimen, employing ultrasonic Lamb waves. Techniques based on the Time-of-Flight (ToF) of the Turning Lamb Mode (TLM) and Direct Lamb Mode (DLM) explored to determine the crack growth. Sensitivity analysis revealed that the Lamb mode with low velocity is more sensitive to crack growth than that of the high velocity Lamb mode.

On the Axial Rigidity of a Perforated Strip and the Strain Energy Release Rate in a Centrally Notched Strip Subjected to Uniaxial Tension

1964 ◽  
Vol 86 (4) ◽  
pp. 693-697 ◽  
Author(s):  
R. G. Forman ◽  
A. S. Kobayashi
Keyword(s):  
Energy Release Rate ◽  
Energy Release ◽  
Uniaxial Tension ◽  
Release Rate ◽  
Strain Energy ◽  
Strain Energy Release Rate ◽  
Strain Energy Release ◽  
Theoretical Studies ◽  
Correction Factors ◽  
Elasticity Solutions

This paper presents theoretical studies on the axial rigidities in strips with circular and elliptical perforations and subjected to uniaxial tension. Greenspan’s original derivations on these axial rigidities [2] were improved by using the elasticity solutions by Howland [6] and Ishida [7] for infinite strips with circular and elliptical perforations, respectively. Finally, the correction factors for centrally notched strips subjected to uniaxial tension were rederived from the above results following the energy approach by Irwin and Kies [3].

Nonlinear Approach for Strain Energy Release Rate in Micro Cantilevers

2010 ◽  
Author(s):  
Arash Kheyraddini Mousavi ◽  
Seyedhamidreza Alaie ◽  
Maheshwar R. Kashamolla ◽  
Zayd Chad Leseman
Keyword(s):  
Surface Roughness ◽  
Crack Propagation ◽  
Energy Release Rate ◽  
Energy Release ◽  
Release Rate ◽  
Strain Energy ◽  
Strain Energy Release Rate ◽  
Strain Energy Release ◽  
Rigid Substrate ◽  
Micro Cantilever

An analytical Mixed Mode I & II crack propagation model is used to analyze the experimental results of stiction failed micro cantilevers on a rigid substrate and to determine the critical strain energy release rate (adhesion energy). Using nonlinear beam deflection theory, the shape of the beam being peeled off of a rigid substrate can be accurately modeled. Results show that the model can fit the experimental data with an average root mean square error of less than 5 ran even at relatively large deflections which happens in some MEMS applications. The effects of surface roughness and/or debris are also explored and contrasted with perfectly (atomically) flat surfaces. Herein it is shown that unlike the macro-scale crack propagation tests, the surface roughness and debris trapped between the micro cantilever and the substrate can drastically effect the energy associated with creating unit new surface areas and also leads to some interesting phenomena. The polysilicon micro cantilever samples used, were fabricated by SUMMIT V™ technology in Sandia National Laboratories and were 1000 μm long, 30 μm wide and 2.6 μm thick.

Influence of Loading History on Delamination in Multilayered Beam with Creep

2021 ◽  
Vol 1046 ◽  
pp. 23-28
Author(s):  
Victor Iliev Rizov
Keyword(s):  
Energy Release Rate ◽  
Energy Release ◽  
Release Rate ◽  
Strain Energy ◽  
Strain Energy Release Rate ◽  
Strain Energy Release ◽  
Time Dependent ◽  
External Loading ◽  
Loading History ◽  
Multilayered Beam

The present paper deals with an analytical study of the time-dependent delamination in a multilayered inhomogeneous cantilever beam with considering of the loading history. The multilayered beam exhibits creep behaviour that is treated by using a non-linear stress-strain-time relationship. The material properties are continuously distributed along the thickness and length of the layers. The external loading is applied in steps in order to describe the loading history. The analysis reveals that during each step of the loading, the strain energy release rate increases with time. The influences of crack length and location on the time-dependent strain energy release rate are also investigated.

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