Matrix and interface microcracking in carbon fiber/polymer structural micro-battery

2019 ◽  
Vol 53 (25) ◽  
pp. 3615-3628 ◽  
Author(s):  
Johanna Xu ◽  
Janis Varna
Keyword(s):  
Carbon Fiber ◽  
Energy Release ◽  
Crack Growth ◽  
Matrix Crack ◽  
Matrix Interface ◽  
Release Rates ◽  
Matrix Cracks ◽  
The Matrix ◽  
Energy Release Rates ◽  
Coating Matrix

In this paper, the propagation of radial matrix cracks and debond cracks at the coating/matrix interface in unidirectional carbon fiber structural micro-battery composite are studied numerically. The micro battery consists of a solid electrolyte-coated carbon fiber embedded in an electrochemically active polymer matrix. Stress analysis shows that high hoop stress in the matrix during charging may initiate radial matrix cracks at the coating/matrix interface. Several 2-D finite element models of the transverse plane with different arrangements of fibers and other matrix cracks were used to analyze the radial matrix crack growth from the coating/matrix interface of the central fiber in a composite with a square packing of fibers. Energy release rates of radial cracks along two potential propagation paths are calculated under pure electrochemical loading. The presence of a radial matrix crack imposes changes in the stress distribution along the coating/matrix interface, making debonding relevant for consideration. Results for energy release rates show that the debond crack growth is governed by mode II.

Three Stages of Fatigue Crack Growth in GFRP Composite Laminates

2000 ◽  
Vol 123 (1) ◽  
pp. 139-143 ◽  
Author(s):  
Jie Tong
Keyword(s):  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Energy Release ◽  
Crack Growth ◽  
Strain Energy ◽  
Strain Energy Release ◽  
Release Rates ◽  
Energy Release Rates ◽  
Three Stages ◽  
Strain Energy Release Rates

Multiple fatigue crack growth behavior has been studied in model transparent GFRP laminates. Detailed experimental observations have been made on the growth of individual fatigue cracks and on the evolution of cracks in off-axis layers in 0/90/±45S and ±45/90S laminates. Three stages of fatigue crack growth in the laminates have been identified: initiation, steady-state crack growth (SSCG), crack interaction and saturation. The results show that SSCG rate is essentially constant under constant load, independent of crack length and crack spacing. Finite element models have been developed and used to calculate the strain energy release rates associated with the off-axis matrix cracking. A correlation has been achieved between fatigue crack growth rates in off-axis layers and the total strain energy release rates.

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.

The Characterization of Mixed-Mode Energy Release Rates in Orthotropic Materials

1996 ◽  
Vol 210 (1) ◽  
pp. 33-42 ◽  
Author(s):  
C A Walker ◽  
Jamasri
Keyword(s):  
Finite Element ◽  
Energy Release Rate ◽  
Energy Release ◽  
Crack Growth ◽  
Release Rate ◽  
Mode I ◽  
Mode Ii ◽  
Finite Element Models ◽  
Release Rates ◽  
Energy Release Rates

The aim of this work was to predict, from the material constants, mixed-mode energy release rates in orthotropic materials, in particular the general cases in which the crack is aligned at a random angle to the principal material direction, normal to the plane of orthotropy. Two-dimensional finite element models with various fibre orientations were generated. The finite element models were validated by comparing two sets of contour plots of deformation, one resulting from the finite element analysis and the other from moiré interferograms of the experimental work. On comparison there was shown to be a strict similarity between experimentally determined and computational deformation fields. Variations of the energy release rates were investigated for both rapid and stable crack growth. This was accomplished by generating two-dimensional stable crack growth finite element models. In general, energy release rates were found to be strongly affected by the fibre orientation. An increase of the angle of the crack growth direction caused a decrease of the mode I energy release rate and, by contrast, an increase of the mode II energy release rate, but the mode II energy release rate was always a small fraction of the mode I value. Crack extension caused a gradual increase of the mode I energy release rate both for coplanar and non-coplanar crack growth. However, there was no significant effect found on the mode II energy release rate.

Criteria for Prediction the Interfacial Crack Growth in Concrete

2016 ◽  
Vol 258 ◽  
pp. 514-517
Author(s):  
Jelena M. Djoković ◽  
Ružica R. Nikolić ◽  
Ján Bujňák ◽  
Branislav Hadzima
Keyword(s):  
Fracture Mechanics ◽  
Mechanical Behavior ◽  
Energy Release ◽  
Crack Growth ◽  
Interfacial Crack ◽  
Release Rates ◽  
Linear Elastic ◽  
Deformation And Fracture ◽  
Energy Release Rates ◽  
Elastic Fracture

To understand the mechanical behavior of the concrete structures, one must analyze deformation and fracture of the interfaces between the constituents of the material that the structure is made of. Criteria for predicting the crack growth along an interface, based on the linear elastic fracture mechanics concept, applied for the cement substrate/aggregate interface, are presented in this paper. The two possible directions of the interfacial crack growth – the crack propagation along the interface and the crack kinking away from the interface are considered, with the corresponding energy release rates. For the case of the crack approaching the interface from one of the materials – cement, the competition between the crack deflecting into the interface and the crack penetrating the interface is considered with the corresponding energy release rates.

Determination of Crack-Growth Characteristics Using the Angled Testpiece

1989 ◽  
Vol 62 (2) ◽  
pp. 219-233 ◽  
Author(s):  
A. H. Muhr ◽  
A. G. Thomas
Keyword(s):  
Energy Release ◽  
Crack Growth ◽  
Strain Energy ◽  
Pure Shear ◽  
Strain Energy Release ◽  
Growth Characteristics ◽  
Release Rates ◽  
Growth Properties ◽  
Energy Release Rates ◽  
Strain Energy Release Rates

Abstract The anticipated advantages of the angled testpiece have been borne out with some important provisos. For sufficiently thin testpieces and high strain-energy release rates, it is possible to use the angled testpiece geometry and the machine described to determine the cyclic crack-growth characteristics without directly measuring the crack length or carrying out auxiliary elasticity measurements. The modifications to the theory for thicker test pieces (for which the buckling force is significant) should allow the technique to be applied, but one of the main advantages over the other techniques (the avoidance of auxiliary elastic measurements) is then lost. It has also become apparent that working at low strain-energy release rates with a machine of this sort calls for a very stable temperature. For this reason, the machine's capability to do such measurements has not yet been assessed. There is broad agreement between results from the various techniques for both time-dependent crack growth (angled, pure-shear, and trouser testpieces of SBR gum) and cyclic crack growth (angled, pure shear, and tensile testpieces of SBR gum and NR gum). However, although the fracture mechanics approach appears to be generally of considerable value in expressing the crack-growth properties of rubbers, giving results that are essentially independent of testpiece geometry, the latter feature is not invariably found. In the present work, significant discrepancies were found for NR gum at low values of T. Such discrepancies are being investigated further.

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