A simplified approach to the damage tolerance design of asymmetric tapered laminates. Part I: Methodology development

Abstract Tapered composite laminates are susceptible to interlaminar damage in the form of delaminations growing from ply drop-off locations. This study presents an analytical method for the calculation of the energy release rates associated with interlaminar cracks emanating from the ply termination in both the laminate thick and thin sections, also accounting for the effects of the tapering angle. The proposed approach is based on modeling asymmetrically tapered composite laminates as assemblies of layered Euler–Bernoulli beam segments; these are split and reconnected through-the-thickness at the ply-drop-off location. The presence of a local resin pocket is explicitly considered in the model. Orthotropic rescaling is employed in order to take into account the material behavior through-the-thickness. This paper presents the analytical formulation of the proposed approach, whose validation follows in part II.

[1]  Zhigang Suo,et al.  Orthotropy rescaling and implications for fracture in composites , 1991 .

[2]  M. Wisnom,et al.  Predicting the effect of through-thickness compressive stress on delamination using interface elements , 2008 .

[3]  A. Karlsson,et al.  On the Reference Length and Mode Mixity for a Bimaterial Interface , 2007 .

[4]  James H. Starnes,et al.  Effect of dropped plies on the strength of graphite-epoxy laminates , 1987 .

[5]  C. Sun,et al.  Effect of compressive transverse normal stress on mode II fracture toughness in polymeric composites , 2007 .

[6]  Their Composites,et al.  Composite Materials: Fatigue and Fracture , 1992 .

[7]  P. Lagacé,et al.  An Analytical Method for Interlaminar Stresses Due to Global Effects of Ply Drop-Offs , 2005 .

[8]  W. Cui,et al.  New model to predict static strength of tapered laminates , 1995 .

[9]  Stephen R Hallett,et al.  On the optimization of tapered composite laminates in preliminary structural design , 2009 .

[10]  Isaac M Daniel,et al.  Composite Materials: Testing and Design , 1982 .

[11]  Heung Soo Kim,et al.  Layup optimization with GA for tapered laminates with internal plydrops , 2006 .

[12]  M. Wisnom,et al.  Delamination in tapered unidirectional glass fibre-epoxy under static tension loading , 1991 .

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

[14]  Erian A. Armanios,et al.  Delamination analysis of tapered laminated composites under tensile loading , 1991 .

[15]  I. Raju.  Calculation of strain-energy release rates with higher order and singular finite elements , 1987 .

[16]  Abhijit Mukherjee,et al.  Design guidelines for ply drop-off in laminated composite structures , 2001 .

[17]  Satish A. Salpekar,et al.  Strain-Energy-Release Rate Analysis of Delamination in a Tapered Laminate Subjected to Tension Load , 1991 .

[18]  Suong V. Hoa,et al.  The study of tapered laminated composite structures: a review , 2000 .

[19]  Shiuh-Chuan Her,et al.  Stress analysis of ply drop-off in composite structures , 2002 .

[20]  B. Cox,et al.  Mode I weight functions for an orthotropic double cantilever beam , 2003 .

[21]  Michael R Wisnom,et al.  Delamination in Asymmetrically Tapered Composites Loaded in Tension , 1996 .

[22]  J. G. Williams,et al.  On the calculation of energy release rates for cracked laminates , 1988 .

[23]  Suong V. Hoa,et al.  Modified shear-lag model for analysis of a composite laminate with drop-off plies , 2003 .

[24]  M. Wisnom,et al.  Parametric study of delamination in composites with discontinuous plies using an analytical solution based on fracture mechanics , 1998 .

[25]  R. Jones,et al.  Mechanics of Composite Materials , 2018 .

[26]  W. Cui,et al.  Failure of tapered composites under static and fatigue tension loading , 1995 .

[27]  George S. Springer,et al.  Design of Composite Laminates for Strength, Weight, and Manufacturability , 1997 .

[28]  A. Vizzini.  Shear-Lag Analysis about an Internally-Dropped Ply , 1997 .

[29]  Suong V. Hoa,et al.  Parameters affecting interlaminar stresses in tapered laminates under static loading conditions , 1989 .

[30]  K Kussmaul,et al.  Characterizing static and fatigue interlaminar fracture behavior of a first generation graphite/epoxy composite , 1997 .

[31]  Sung W. Lee,et al.  Delamination of tapered composite structures , 1989 .

[32]  S. Brown,et al.  Ply drop-off effects in CFRP/honeycomb sandwich panels—theory , 1996 .

[33]  F. C. Campbell.  Manufacturing Processes for Advanced Composites , 2012 .

[34]  A. V. Krishna Murty,et al.  Analysis of laminates with ply drops , 2001 .

[35]  Stephen W. Tsai,et al.  Design Optimization of Composite Plates: Part II—Structural Optimization by Plydrop Tapering , 1998 .