Fracture analysis of composite co-cured structural joints using decohesion elements

Delamination is one of the predominant forms of failure in laminated composite structures, especially when there is no reinforcement in the thickness direction. To develop composite structures that are more damage tolerant, it is necessary to understand how delamination develops, and how it can affect the residual performance. A number of factors such as residual thermal stresses, matrix-curing shrinkage and manufacturing defects affect how damage will grow in a composite structure. It is important to develop computationally efficient analysis methods that can account for all such factors. The objective of the current work is to apply a newly developed decohesion element to investigate the debond strength of skin-stiffener composite specimens. The process of initiation of delaminations and the propagation of delamination fronts is investigated. The numerical predictions are compared with published experimental results.

[1]  D. S. Dugdale.  Yielding of steel sheets containing slits , 1960 .

[2]  Pierre J. A. Minguet,et al.  A Method for Calculating Strain Energy Release Rates in Preliminary Design of Composite Skin/Stringer Debonding Under Multi-Axial Loading , 1999 .

[3]  M. Kanninen,et al.  A finite element calculation of stress intensity factors by a modified crack closure integral , 1977 .

[4]  Michael R Wisnom,et al.  PREDICTION OF DELAMINATION INITIATION AND GROWTH FROM DISCONTINUOUS PLIES USING INTERFACE ELEMENTS , 1998 .

[5]  P. Camanho,et al.  Mixed-Mode Decohesion Finite Elements for the Simulation of Delamination in Composite Materials , 2002 .

[6]  John H. Crews,et al.  The mixed-mode bending method for delamination testing , 1989 .

[7]  de R René Borst,et al.  On the numerical integration of interface elements , 1993 .

[8]  N. Pagano,et al.  Stress fields and energy release rates in cross-ply laminates , 1998 .

[9]  Pedro P. Camanho,et al.  Numerical Simulation of Delamination Growth in Composite Materials , 2001 .

[10]  G. I. Barenblatt.  THE MATHEMATICAL THEORY OF EQUILIBRIUM CRACKS IN BRITTLE FRACTURE , 1962 .

[11]  Jr. J. Crews,et al.  Mixed-Mode Bending Method for Delamination Testing , 1990 .

[12]  J. Reeder,et al.  An Evaluation of Mixed-Mode Delamination Failure Criteria , 1992 .

[13]  Pierre J. A. Minguet,et al.  Testing and Analysis of Composite Skin/Stringer Debonding Under Multi-Axial Loading , 1999 .

[14]  J. Rice.  A path-independent integral and the approximate analysis of strain , 1968 .

[15]  J. Whitney,et al.  Stress Fracture Criteria for Laminated Composites Containing Stress Concentrations , 1974 .

[16]  M. Benzeggagh,et al.  Measurement of mixed-mode delamination fracture toughness of unidirectional glass/epoxy composites with mixed-mode bending apparatus , 1996 .

[17]  Jian Li,et al.  ANALYSIS OF FRAME-TO-SKIN JOINT PULL-OFF TESTS AND PREDICTION OF THE DELAMINATION FAILURE1 , 2001 .

[18]  P.M.S.T. de Castro,et al.  Interface element including point‐to‐surface constraints for three‐dimensional problems with damage propagation , 2000 .

[19]  C. Dávila,et al.  Analysis of delamination initiation in postbuckled dropped-ply laminates , 1963 .

[20]  F. L. Matthews,et al.  Delamination Onset Prediction in Mechanically Fastened Joints in Composite Laminates , 1999 .

[21]  E. M. Wu,et al.  CRACK EXTENSION IN FIBERGLASS REINFORCED PLASTICS , 1965 .

[22]  C. Sun,et al.  On strain energy release rates for interfacial cracks in bi-material media , 1987 .

[23]  Krueger Ronald,et al.  A Shell/3D Modeling Technique for the Analysis of Delaminated Composite Laminates , 2000 .

[24]  Michael R Wisnom,et al.  A combined stress-based and fracture-mechanics-based model for predicting delamination in composites , 1993 .

[25]  Ran Y. Kim,et al.  Experimental and Analytical Studies On the Onset of Delamination in Laminated Composites , 1984 .