T650/AFR-PE-4/FM680-1 Mode I Critical Energy Release Rate at High Temperatures: Experiments and Numerical Models

An experimental program to determine the mode I critical energy release rate (GIc) of the T650/AFR-PE-4/FM680-1 material system is reported. Two forms of GIc are determined over the range of 20 to 350 C, the area method critical energy release rate G a and the inverse method critical energy release rate (G i). The value of GIc was found to increase with increasing temperature. The inverse method is determined to be a very effective method of determining GIc over the entire range of temperatures. Inverse modeling was completed using the finite element method, coupled with a novel Discrete Cohesive Zone Element, to determine G i over the range of crack advance in a given specimen. The element is described in detail, as well as the metrics used by the inverse algorithm. The FE models, subsequent to inverse modeling, accurately reproduce the experimental load-displacement curves. They therefore provide a capable analysis method, as well as a material system constitutive relation that contains a range of appropriate properties for use in the design and analysis of T650/AFR-PE-4/FM680-1 joints. Nomenclature GI Energy release rate, J/m 2 GIc Critical energy release rate, J/m 2 G a Area method critical energy release rate, J/m 2 G i Inverse method critical energy release rate, J/m 2 c Cohesive strength of the adhesive system, N/m 2

[1]  P.M.S.T. de Castro,et al.  A three-dimensional finite element model for stress analysis of adhesive joints , 2002 .

[2]  De Xie,et al.  Computation of Energy Release Rates for Kinking Cracks based on Virtual Crack Closure Technique , 2004 .

[3]  Xiaopeng Xu,et al.  Numerical simulations of fast crack growth in brittle solids , 1994 .

[4]  Wolfgang G. Knauss,et al.  The role of damage-softened material behavior in the fracture of composites and adhesives , 1987 .

[5]  Zenon Mróz,et al.  Finite element analysis of deformation of strain‐softening materials , 1981 .

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

[7]  René de Borst,et al.  Some recent issues in computational failure mechanics , 2001 .

[8]  M. Ortiz,et al.  Computational modelling of impact damage in brittle materials , 1996 .

[9]  J. Hutchinson,et al.  The relation between crack growth resistance and fracture process parameters in elastic-plastic solids , 1992 .

[10]  G. R. Wooley,et al.  Stress Concentration Factors for Bonded Lap Joints , 1971 .

[11]  Laurent Champaney,et al.  A damage-mechanics-based approach for modelling decohesion in adhesively bonded assemblies , 2006 .

[12]  R. Borst.  Numerical aspects of cohesive-zone models , 2003 .

[13]  Ronald Krueger,et al.  The Virtual Crack Closure Technique : History , Approach and Applications , 2002 .

[14]  I. Raju,et al.  Fracture mechanics analyses of composite skin-stiffener debond configurations with shell elements , 1994 .

[15]  P. Ladevèze,et al.  INTERFACIAL APPROACH OF DELAMINATION: POSSIBILITIES AND DIFFICULTIES , 1999 .

[16]  Jr C. C. Poe,et al.  Fracture Mechanics Analysis of Stitched Stiffener-Skin Debonding , 1998 .

[17]  De Xie,et al.  Discrete Cohesive Zone Model To Simulate Static Fracture In Carbon Fiber Textile Composites , 2005 .

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

[19]  De Xie,et al.  Fracture criterion for kinking cracks in a tri-material adhesively bonded joint under mixed mode loading , 2005 .

[20]  G.A.O. Davies,et al.  Predicting delamination and debonding in modern aerospace composite structures , 2006 .

[21]  Barry D. Davidson,et al.  Evaluation of energy release rate-based approaches for predicting delamination growth in laminated composites , 2000 .

[22]  Christopher D. Cassino,et al.  Computational Model for Progressive Failure of Adhesively Bonded Joints , 2003 .

[23]  L. Asp.  The effects of moisture and temperature on the interlaminar delamination toughness of a carbon/epoxy composite , 1998 .

[24]  Robert D. Adams,et al.  Stress analysis of adhesive-bonded lap joints , 1974 .

[25]  M. D. Thouless,et al.  The effects of geometry and material properties on the fracture of single lap-shear joints , 2002 .

[26]  De Xie,et al.  Discrete cohesive zone model for mixed-mode fracture using finite element analysis , 2006 .

[27]  De Xie,et al.  Progressive crack growth analysis using interface element based on the virtual crack closure technique , 2006 .

[28]  M. D. Thouless,et al.  Competing failure mechanisms in mixed-mode fracture of an adhesively bonded polymer-matrix composite , 2006 .

[29]  De Xie,et al.  Discrete Cohesive Zone Model to Simulate Static Fracture in Carbon Fiber Composites , 2005 .

[30]  John W. Gillespie,et al.  Finite element analysis of the end notched flexure specimen for measuring mode II fracture toughness , 1986 .

[31]  J. Molinari,et al.  Dynamic crack propagation with cohesive elements: a methodology to address mesh dependency , 2004 .

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

[33]  M. D. Thouless,et al.  Use of a cohesive-zone model to analyze the fracture of a fiber-reinforced polymer-matrix composite , 2005 .

[34]  Ugo Galvanetto,et al.  On the numerical simulation of fatigue driven delamination with interface elements , 2006 .

[35]  T. Collins,et al.  Mechanical Properties of T650-35/AFR-PE-4 at Elevated Temperatures for Lightweight Aeroshell Designs , 2006 .

[36]  Anthony M. Waas,et al.  Non–self–similar decohesion along a finite interface of unilaterally constrained delaminations , 1997, Proceedings of the Royal Society of London. Series A: Mathematical, Physical and Engineering Sciences.