Structural scale decomposition of energy release rates for delamination propagation

2003 ◽  
Vol 122 (1/2) ◽  
pp. 89-100 ◽  
Author(s):  
W.J. Bottega
Keyword(s):  
Energy Release ◽  
Release Rates ◽  
Energy Release Rates ◽  
Structural Scale ◽  
Delamination Propagation

Effect of Material Anisotropy and Curing Stresses on Interface Delamination Propagation Characteristics in Multiply Laminated FRP Composites

2005 ◽  
Vol 128 (3) ◽  
pp. 383-392 ◽  
Author(s):  
Brajabandhu Pradhan ◽  
Saroja Kanta Panda
Keyword(s):  
Energy Release ◽  
Composite Structures ◽  
Material Anisotropy ◽  
Interlaminar Stresses ◽  
Release Rates ◽  
Frp Composites ◽  
Energy Release Rates ◽  
The Individual ◽  
Delamination Front ◽  
Delamination Propagation

The present study encompasses the thermoelastic effect of material anisotropy and curing stresses on interlaminar embedded elliptical delamination fracture characteristics in multiply laminated fiber-reinforced polymeric (FRP) composites. Two sets of full three-dimensional finite element analyses have been performed to calculate the displacements and interlaminar stresses along the delaminated interface responsible for the delamination onset and propagation. Modified crack closure integral methods based on the concepts of linear elastic fracture mechanics have been followed to evaluate the individual modes of strain energy release rates along the delamination front. It is shown that the individual modes of energy release rates vary along the delamination front depending on the ply sequence, orientation, and thermoelastic material anisotropy of the constituting laminae. This causes the anisotropic and non-self similar delamination propagation along the interface. The asymmetric and nonuniform variations in the nature of energy release rate plots obtained in a thermomechanical loading environment are significant when curing stress effects are included in the numerical analysis and hence should be taken into account in the designs of laminated FRP composite structures.

Research of Underfill Delamination in Flip Chip by the J-Integral Method

2004 ◽  
Vol 126 (1) ◽  
pp. 94-99 ◽  
Author(s):  
Bulu Xu ◽  
Xia Cai ◽  
Weidong Huang ◽  
Zhaonian Cheng
Keyword(s):  
Energy Release ◽  
Thermal Cycle ◽  
Flip Chip ◽  
Electronic Packages ◽  
J Integral ◽  
Release Rates ◽  
Energy Release Rates ◽  
Cycle Loading ◽  
Scanning Acoustic Microscope ◽  
Delamination Propagation

Fracture mechanics approaches have been used to study reliability problems in electronic packages, in particular, adhesion related failure in flip chip assembly. It was verified in this work that the J-integral with a special flat rectangular contour near the crack tip can be used as energy release rate at the interface between chip and underfill. Meanwhile, the delamination propagation rates at the interface was measured by using C-mode scanning acoustic microscope (C-SAM) inspection for two types of flip chip packages under thermal cycle loading. Finally, the half-empirical Paris equation, which can be used as a design base of delamination reliability in flip chip package, has been determined from the crack propagation rates measured and the energy release rates simulated.

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