scholarly journals Interaction of Mixed Mode Loading on Cyclic Debonding in Adhesively Bonded Composite Joints

1987 ◽  
Vol 109 (1) ◽  
pp. 17-21 ◽  
Author(s):  
S. Mall ◽  
M. A. Rezaizadeh ◽  
R. Gurumurthy
Keyword(s):  
Mixed Mode ◽  
Strain Energy ◽  
Strain Energy Release ◽  
Analytical Investigation ◽  
Mode I ◽  
Adhesively Bonded ◽  
Total Strain Energy ◽  
Composite Joint ◽  
Governing Factor ◽  
Bonded Composite

A combined experimental and analytical investigation of an adhesively bonded composite joint was conducted to characterize the fracture mode dependence of cyclic debonding. The system studied consisted of graphite/epoxy adherends bonded with EC 3445 adhesive. Several types of specimens were tested which provided the cyclic debond growth rate measurements under various load conditions: mode I, mixed mode I and II, and almost mode II. This study showed that the total strain-energy-release rate was the governing factor for cyclic debonding.

scholarly journals Analysis of Mixed Mode I/II/III Fracture in Foam Core Sandwich Structures Using Imposed Displacement Split Cantilever Beams

2015 ◽  
Vol 45 (3) ◽  
pp. 69-82
Author(s):  
V. Rizov
Keyword(s):  
Finite Element ◽  
Energy Release Rate ◽  
Energy Release ◽  
Release Rate ◽  
Mixed Mode ◽  
Strain Energy ◽  
Strain Energy Release Rate ◽  
Strain Energy Release ◽  
Mode I ◽  
Foam Core

Abstract Static fracture in foam core sandwich structures under mixed mode I/II/III loading conditions was studied theoretically. In order to generate such loading conditions, a thread guide was used to impose in- plane displacements of the lower crack arm of a sandwich Split Cantilever Beam (SCB). The upper crack arm was loaded by a transverse force. A three-dimensional finite element model of the imposed displacement sandwich SCB configuration was developed. The fracture was studied applying the concepts of linear-elastic fracture mechanics. The strain energy release rate mode components distribution along the crack front was analyzed using the virtual crack closure technique. The influence of the imposed displacement magnitude and the crack length on the fracture was evaluated. The effect of the sandwich core material on the mixed-mode I/II/III fracture was studied. For this purpose, finite element simulations were carried-out assuming that the core is made by different rigid cellular foams. It was found that the strain energy release rate decreases when the foam density increases.

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.

The Edge Delamination Test: Measuring the Critical Adhesion Energy of Thin-Film Coatings, Part II: Mode Mixity & Application

1994 ◽  
Vol 338 ◽  
Author(s):  
Edward O. Shaffer ◽  
Scott A. Sikorski ◽  
Frederick J. McGarry
Keyword(s):  
Thin Film ◽  
Energy Release Rate ◽  
Energy Release ◽  
Release Rate ◽  
Strain Energy ◽  
Strain Energy Release Rate ◽  
Strain Energy Release ◽  
Mode I ◽  
Rigid Substrate ◽  
Edge Delamination

ABSTRACTThe edge delamination test (EDT) is being developed to measure the critical energy required to cause a thin film, under biaxial tensile stress, to debond from a rigid substrate[1]. The test uses circular features etched through biaxially stressed films adhered to a rigid substrate. If the stress is large enough, a stable debond ring grows radially about the feature. We use a finite element analysis to model the test, solving for the applied strain energy release rate as a function of crack length, feature hole radius and other geometrical parameters. The model identifies both mode I and mode II components of the strain energy release rate, and agrees with previous analytical solutions for the total debond energy. However, the model predicts, with a very refined mesh at the crack tip, the fracture process is pure mode I. To explore this result, critical strain energy release rates from the EDT and the island blister test (IBT) are compared. This agreement supports the model prediction that the failure process in the EDT is modeI peeling.

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