C. RESIDUAL STRESSES AND PROCESSING
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Modeling the Dimensional Variations of Composites Induced by
Processing Defects
C Dong (Curtin Univ of Technology)
A model of the dimensional variations of composites induced by processing defects is
presented in this paper. The processing-induced resin-rich zones were characterized
quantitatively and the dimensional variations were computed by finite element analysis.
Based on the result, a regression based model was developed. (C4:1)
Integrated Finite Element Environment for Composite Process
Simulation
T Garstka, G Cole, D Irving, P Lyons (LUSAS)
In this paper the LUSAS High Precision Moulding (HPM) integrated finite element
environment for composite process simulation is introduced and validated against test
components with single and double curvatures. Presented results show dependence on the
laminate thickness, radius and in-plane dimensions, these agree with experimental data and
analytical models. (C4:2)
A Modelling Approach for Predicting Residual Stresses and Distortions
in Polymer Composites
S Lord, G Stringer (QinetiQ)
A tool has been developed which uses a multi-scale modelling approach, which starts from
the fundamental resin chemistry and proceeds to structural finite element analysis, to predict
the residual stresses and distortions in the manufacture of fibre-reinforced composite parts.
(C4:3)
A Graded Tetrahedal Element for Thermoelastic Analysis of Complex
Laminated Structures
A Jones, A Long (Univ of Nottingham) W Ruijter (formerly Univ of Nottingham)
A novel finite element has been developed to allow automatically-generated tetrahedral
meshes for composite structures, particularly for thermoelastic modelling of shrinkage and
distortion. Elastic moduli and CTEs are defined as polynomials in through-thickness position
to give elastic and thermal behaviour equivalent to those of a laminate. (C4:4)
Integrating the Simulation of Flow and Stress Development During
Processing of Thermoset Matrix Composites
M Haghshenas, R Vaziri, A Poursartip (Univ of BC
Current FE based models for the processing of thermoset composites deal with either flow
(pre-gelation) or stress development (post-gelation), and there is currently no means of
rigorously combining the two. We present a framework to address this issue, with the ultimate
goal of predicting the geometry and stress state of the final cured part. (C4:5)
Thursday
09.10
Measurement of Process-Induced Strains by Fibre Bragg Grating Optic
Sensor in Resin Transfer Moulding
P Hubert, L Khoun (McGill Univ) R De Oliveira, V Michaud (EPFL)
Process-induced strains were measured using fibre optic sensors in composite panels
manufactured by resin transfer moulding. The sensors captured a strain variation during the
cool-down related to the debonding of the composite from the mould. The measured tool-part
interaction was simulated with the finite element method using contact constraints. (C4:6)
Settling of Glass Woven Fabric in Steel RTM Mould: Impact on Residual
Stresses?
J Balvers, H Bersee (TU Delft)
With embedded fibre Bragg grating sensors it is proven that thermal loading of steel RTM
mould containing glass woven fabrics leads to different behaviour when fabric still has to
settle. Heating and cooling along the same trajectory do not imply a reversible process with
respect to expansion/contraction of the preform. (C4:7)
Through-Thickness Cure Monitoring of Thick Advanced Composites
using Dielectric Sensors
M-A Octeau, J Chen, A Yousefpour (National Research Council Canada) J Balvers, H Bersee
(TU Delft)
In this study, resin transfer moulding is used to fabricate thick composite flat panels. Since
manufacturing of thick panels is accompanied with many processing problems due to the
exothermic reaction of the resin system, dielectric sensors are embedded to measure the
effect of the exothermic reaction on the through-thickness progress of the curing state.
(C4:8)
Gas Transport in Prepregs: Model and Permeability Experiments
G Fernlund, A Arafath, A Poursartip (Univ of British Columbia)
The extent to which gas can be removed from a laminate is largely dependent on the gas
permeability of the prepreg. In this study, tests were performed on T800H/3900-2 tape and
fabric prepregs to study the effect of laminate thickness, lay-up orientation and material form
on laminate gas permeability. (C4:9)
Thermal Isolation Techniques for Cure Monitoring using FBG Optical
Sensors
E Boateng, P Schubel, N Warrior (Univ of Nottingham)
This paper reports on thermal isolation simulation and experimental techniques for Fibre
Bragg Grating (FBG) sensors used for cure monitoring of thermoset composites. Current
studies have focused on the use of prepreg materials used in the wind energy industry.
(C4:10)
Variation in Shape Distortion due to Corner Thinning/Thickening of
Prepreg
M Svanberg (Swerea Sicomp) P Hallander, T Nyman (Saab Aerostructures)
Shape distortion of composite corners during traditional prepreg manufacturing due to corner
thinning/thickening has been investigated. Components have been manufactured on a mould
with both male and female corners using prepreg with both “unsolved thoughener” and
“solved thoughener”. In addition two cure assemblies have been used to alter the corner
effects. (C4:11)