F. DELAMINATION
oral
Double Notch Split Cantilever Test Method to Measure Mixed Mode II and III
Interlaminar Toughness
H Suemasu, A Kondo, K Gozu (Sophia Univ) Y Aoki (JAXA)
NEEDS 50 WORD ABSTRACT
(F9:1)
Experimental Method for Estimating Dynamic Fracture Toughness of
Polymer Matrix Composite Laminates
T Kusaka (Ritsumeikan Univ)
NEEDS 50 WORD ABSTRACT
(F9:2)
Effect of Stress Ratio on Delamination Growth in Unidirectional
Carbon/Epoxy Under Mode I and Mode II Fatigue Loading
R Khan, C Rans, R Benedictus (TU Delft)
NEEDS 50 WORD ABSTRACT
(F9:3)
Fatigue Structural Substantiation for Thick Composites
A Makeev (Georgia Institute of Technology)
This work shows the effect of nonlinear interlaminar shear stress-strain relations on delamination
failure predictions for thick IM7/8552 Carbon/Epoxy tape composites with fiber waviness defects.
Constitutive properties including interlaminar stress-stress relations and fatigue curves are
generated; structural failure models are developed; and subsequent test correlations are
presented. (F9:4)
Static And Fatigue Delamination From Discontinuous Plies - Experimental
And Numerical Investigations
L Kawashita, M Jones, R Trask, S Hallett, MR Wisnom (Univ of Bristol)
Cut ply specimens of IM7/8552 carbon/epoxy laminates were tested under monotonic and cyclic
tensile loading. Experimental results were used to validate new cohesive interface element
formulations for static and fatigue delamination. Results are presented in terms of static failure
loads and fatigue crack growth rates. (F9:5)
14.10
Modeling of Adhesive Layers of Laminated Plates in Delamination
Simulation
G Shi, H Zhang (Tianjin Univ)
This paper first reviews the various modeling techniques for the interfacial layers of laminated
plates in the delamination simulation of composite plates, such as various types of interface
elements and corresponding material models. Then it presents a new 3-D interface element
based on the solid-shell element and damage mechanics for delamination simulation. (F9:6)
Finite Element Delamination Study of a Notched Composite Plate under
Flexural Loads
A André, S Nilsson, L Asp (Swerea Sicomp AB)
A finite element analysis was conducted to study delamination onset and propagation in bending
loaded notched composite plates using cohesive interface elements. It was shown that the
damage model can predict damage initiation and subsequent propagation. It was also shown that
damage is redistributed if several cohesive layers are modelled. (F9:7)
Formulating an Effective Strain Energy Release Rate for a Linear Elastic
Fracture Mechanics Description of Delamination Growth
C Rans (Delft Univ of Technology) R Alderliesten (Technical Univ of Delft)
Although the use of strain energy release rate for characterizing delamination growth behaviour in
composites is common, consensus has not been reached on formulating an effective strain
energy release rate parameter. This paper demonstrates that a logical formulation for such a
parameter exists. (F9:8)
Crack Modelling Without Additional Degrees of Freedom
T Yamanaka, V Feret, L Lessard (McGill Univ)
Modelling delamination by conventional FEM requires a pre-defined location and growth path of
delamination. A new modelling technique called Assumed Displacement Discontinuity FEM
(ADD-FEM) is developed to overcome the difficulties of conventional techniques. The ADD-FEM
results are compared with standard FEM and mixed mode tests by DCB specimens. (F9:9)
Damage Modelling and Prognosis of Delaminated Composite Beam
Structures in Bending
D Thompson, MR Wisnom (Univ of Bristol)
This paper presents the findings of parametric finite element modelling studies, into the effects of
delamination damage throughout the stress and strain fields of composite cantilever beams in
bending under uniform pressure loading. The characteristic damage effects are then utilised to
propose a potential technique for composite structural prognosis. (F9:10)
16.10
F. DELAMINATION
The Effect of Viscoelastic Interface Crack Upon Dynamic Fracture Behavior
of Foam Core Composite Sandwich
S Sun, H Chen (Dalian Univ of Technology)
An interface fracture analysis model called three material media model is established for the
dynamic fracture analysis of sandwich beam. The three-parameter standard solid model behaves
the viscoelasticity of the adhesive layer. The effects of inertia and interfacial viscoelasticity on
fracture behavior are studied based on finite element method. (F9:11)
Multilevel Analysis of Delamination Initiated near the Edges of Composite
Structures
N Carrere, T Vandellos (Onera) E Martin (LCTS)
The present study is aimed at developing a method to describe delamination initiated near the
edges on composite structures. Three aspects are developed: (i) the modeling of the singular
stress fields near the edge, (ii) two complementary methods to predict the onset of delamination
and (iii) multilevel strategy. (F9:12)
Assesment of the Performance of Interface Elements for the Simulation of
Fatigue Induced Delamination
U Galvanetto (Padua Univ) P Robinson, CL Armas (Imperial College London) A Cerioni
(Universita)
Interface elements have recently been used in the simulation of fatigue induced crack
propagation. This work presents a one degree of freedom mathematical model which can be
used to assess systematically the performance of different interface element formulations in an
efficient and rational way. (F9:13)
Investigation of Thermal Effects on Matrix Cracking and Prediction of
Delamination in Composite T-Piece Specimens
J Chen (Univ of Portsmouth)
This paper investigates the thermal effects on matrix crack initiation and prediction of
delamination in composite T-piece specimens under T-pull loading using interface cohesive
models. Thermal shrinkage failure was simulated by presenting an initial crack in the deltoid
region of T-piece. Thermal effect on the prediction of dominated delamination was also studied.
(F9:14)
Evaluation of the Elastic Energy Release Rates of Transversal and
Delamination Cracks in [0/90] Carbon-Epoxi Symmetric Laminates
A Blazquez, F París, B Alberto, M Vladislav (Univ of Sevilla) N McCartney (NPL)
The evolution of the Energy Release Rates (ERR) of a transversal crack and of a delamination
crack in a [0/90]s carbon-epoxy laminate loaded in tension are analyzed. The Boundary Element
Method (BEM) and the Virtual Crack Closure Technique (VCCT) are used in the numerical
analysis, a generalized plane strain state being assumed in the laminate. Numerical results are
corroborated with experiments. (F9:15)
Delamination Model for Cross-Ply Laminates Subject to Triaxial Loading
N McCartney (NPL) A Blazquez (Univ of Seville)
This paper addresses the issue of using energy balance methods to predict the onset of
delamination from ply cracks during the progressive loading of cross-ply laminates subject to
combinations of in-plane biaxial, through-thickness loading, out-of-plane biaxial bending and
thermal residual stresses. (F9:16)