Use of an elasto-plastic model and strain measurements of embedded fibre Bragg grating sensors to detect Mode I delamination crack propagation in woven cloth (0/90) composite materials

2017 ◽  
Vol 17 (2) ◽  
pp. 363-378 ◽  
Author(s):  
Ayad Arab Kakei ◽  
Mainul Islam ◽  
Jinsong Leng ◽  
Jayantha A Epaarachchi

Mode I fracture analysis being employed to study delamination damage in fibre-reinforced composite structures under in-plane and out-of-plane load applications. However, due to the significantly low yield strength of the matrix material and the infinitesimal thickness of the interface matrix layer, the actual delamination process can be assumed as a partially plastic process (elasto-plastic). A simple elasto-plastic model based on the strain field in the vicinity of the crack front was developed for Mode I crack propagation. In this study, a double cantilever beam experiment has been performed to study the proposed process using a 0/90-glass woven cloth sample. A fibre Bragg grating sensor has embedded closer to the delamination to measure the strain at the vicinity of the crack front. Strain energy release rate was calculated according to ASTM D5528. The model predictions were comparable with the calculated values according to ASTM D5528. Subsequently, a finite element analysis on Abaqus was performed using ‘Cohesive Elements’ to study the proposed elasto-plastic behaviour. The finite element analysis results have shown a very good correlation with double cantilever beam experimental results, and therefore, it can be concluded that Mode I delamination process of an fibre-reinforced polymer composite can be monitored successfully using an integral approach of fibre Bragg grating sensors measurements and the prediction of a newly proposed elasto-plastic model for Mode I delamination process.

2000 ◽  
Vol 123 (2) ◽  
pp. 191-197 ◽  
Author(s):  
Y. Shindo ◽  
K. Horiguchi ◽  
R. Wang ◽  
H. Kudo

An experimental and analytical investigation in cryogenic Mode I interlaminar fracture behavior and toughness of SL-E woven glass-epoxy laminates was conducted. Double cantilever beam (DCB) tests were performed at room temperature (R.T.), liquid nitrogen temperature (77 K), and liquid helium temperature (4 K) to evaluate the effect of temperature and geometrical variations on the interlaminar fracture toughness. The fracture surfaces were examined by scanning electron microscopy to verify the fracture mechanisms. A finite element model was used to perform the delamination crack analysis. Critical load levels and the geometric and material properties of the test specimens were input data for the analysis which evaluated the Mode I energy release rate at the onset of delamination crack propagation. The results of the finite element analysis are utilized to supplement the experimental data.


2005 ◽  
Author(s):  
J. C. C. Silva ◽  
A. Ramos ◽  
L. Carvalho ◽  
R. N. Nogueira ◽  
A. Ballu ◽  
...  

2015 ◽  
Vol 133 ◽  
pp. 157-165 ◽  
Author(s):  
Tadayoshi Yamanaka ◽  
Hossein Ghiasi ◽  
Mohammad Heidari-Rarani ◽  
Larry Lessard ◽  
Victor Feret ◽  
...  

2020 ◽  
Vol 55 (2) ◽  
pp. 277-289
Author(s):  
Mingqing Yuan ◽  
Haitao Zhao ◽  
Li Tian ◽  
Boming Zhang ◽  
Yanzhi Yang ◽  
...  

A mixed mode crack density estimation method based on the finite element analysis (FEA) for laminated composites is proposed and verified in this paper. The damaged properties of cracked ply are obtained using semi-analytical micro-mechanical method for the first time. The piecewise functions of the mode I and mode II energy release rates involving crack density are given based on Griffith’s energy principle and discrete damage mechanics (DDM). Any mixed mode fracture criteria could be simply applied to the FEA of the structure to calculate the initiation and evolution of the micro-cracks in the laminate. Mode I criterion, power law and B-K criterion are applied in the numerical examples to compare their performances in the crack density estimation. It has been concluded that the accuracy of the fracture toughness is more important than the choice of fracture criterion in crack density estimation.


2011 ◽  
Vol 488-489 ◽  
pp. 605-608 ◽  
Author(s):  
Matthias Ressel ◽  
Holger Theilig

Several hypotheses and concepts exist for the prediction of crack deflection angles from the analysis of the undisturbed stress distribution at the crack front. In this paper, a finite element analysis of small penny shaped secondary cracks with deflection angles ψ0 = π/4 at a pure mode III loaded crack front is presented. The results are compared with the solutions of the well-known 3D fracture criteria. The fracture mechanical analysis is performed by the highly effective MVCCI-method.


Author(s):  
Mark Cohen ◽  
Xin Wang

In this paper, extensive three-dimensional finite element analysis is conducted to study the asymmetric four-point shear (AFPS) specimen: a widely used mixed mode I/II fracture test specimen. Complete solutions of fracture mechanics parameters KI, KII, KIII, T11, and T33 have been obtained for a wide range of a/W and t/W geometry combinations. It is demonstrated that the thickness of the specimen has a significant effect on the variation of fracture parameter values. Their effects on crack tip plastic zone are also investigated. The results presented here will be very useful for the toughness testing of materials under mixed-mode loading conditions.


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