Determination of mode I & II strain energy release rates in composite foam core sandwiches. An experimental study of the composite foam core interfacial fracture resistance

2017 ◽  
Vol 111 ◽  
pp. 134-142 ◽  
Author(s):  
Owaisur Rahman Shah ◽  
Mostapha Tarfaoui
Keyword(s):  
Fracture Resistance ◽  
Strain Energy ◽  
Strain Energy Release ◽  
Mode I ◽  
Foam Core ◽  
Release Rates ◽  
Composite Foam ◽  
Energy Release Rates ◽  
Strain Energy Release Rates

scholarly journals Geometrically Nonlinear Analysis of Adhesively Bonded Joints

1984 ◽  
Vol 106 (1) ◽  
pp. 59-65 ◽  
Author(s):  
B. Dattaguru ◽  
R. A. Everett ◽  
J. D. Whitcomb ◽  
W. S. Johnson
Keyword(s):  
Energy Release ◽  
Strain Energy ◽  
Strain Energy Release ◽  
Mode I ◽  
Mode Ii ◽  
Geometrically Nonlinear ◽  
Release Rates ◽  
Lap Shear ◽  
Energy Release Rates ◽  
Strain Energy Release Rates

A geometrically nonlinear finite-element analysis of cohesive failure in typical joints is presented. Cracked-lap-shear joints were chosen for analysis. Results obtained from linear and nonlinear analysis show that nonlinear effects, due to large rotations, significantly affect the calculated mode I, crack opening, and mode II, inplane shear, strain-energy-release rates. The ratio of the mode I to mode II strain-energy-release rates (GI/GII) was found to be strongly affected by the adhesive modulus and the adherend thickness. GI/GII ratios between 0.2 and 0.8 can be obtained by varying adherend thickness and using either a single or double cracked-lap-shear specimen configuration. Debond growth rate data, together with the analysis, indicate that mode I strain-energy-release rate governs debond growth. Results from the present analysis agree well with experimentally measured joint opening displacements.

scholarly journals Delamination Resistance Of Laminate Made With VBO MTM46/HTS Prepreg

2015 ◽  
Vol 9 (3) ◽  
pp. 173-177 ◽  
Author(s):  
Piotr Czarnocki ◽  
Kamila Czajkowska
Keyword(s):  
Mixed Mode ◽  
Strain Energy ◽  
Strain Energy Release ◽  
Mode I ◽  
Release Rates ◽  
Delamination Resistance ◽  
Energy Release Rates ◽  
Out Of Autoclave ◽  
Curing Pressure ◽  
Strain Energy Release Rates

Abstract A laminate made with the Vacuum Bag Only (VBO) prepregs can be cured out of autoclave. Because of low curing pressure such a process can result in deterioration of laminate mechanical properties. They can be significantly lower than those displayed by the autoclave cured ones. The resistance against delamination can be among the most affected. Since this property is a week point of all the laminates it was of particular interest. Delamination resistance of unidirectional laminate made from VBO MTM46/HTS(12K) prepreg was in the scope of the presented research and the critical values of the Strain Energy Release Rates and the Paris-type equations corresponding to Mode I, Mode II and Mixed-Mode I/II static and cyclic loadings, respectively, were determined.

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.

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