- Library Home /
- Search Collections /
- Open Collections /
- Browse Collections /
- UBC Theses and Dissertations /
- Effect of processing on the behaviour of laminated...
Open Collections
UBC Theses and Dissertations
UBC Theses and Dissertations
Effect of processing on the behaviour of laminated composite structures : a numerical and probabilistic approach Arafath, Abdul Rahim Ahamed
Abstract
The manufacturing of composite structures made of fibre-reinforced thermoset matrix materials generally results in residual stress build-up during the curing process. As a consequence, the precise geometry and material properties of the final structure after tool (mould) removal are often difficult to control. To account for such process-induced variations, engineers either have employed empirical knockdown factors, which are determined experimentally for a range of distinct structures, materials and manufacturing processes or have incorporated the measured variations as input into sophisticated finite element analyses. The first approach may lead to an unconservative design while the second approach is not suitable for normal design practice. In this study, a combined deterministic-stochastic simulation approach is presented to demonstrate the manner in which manufacturing-induced variabilities in composite structures can be controlled to achieve targeted reliability levels in structural performance. A finite element code, COMPRO, which deterministically simulates the various physical phenomena during manufacturing of composite structures, is integrated with non-linear structural analysis and reliability analysis to compute the statistics of the parameters that must be controlled at the manufacturing level in order to result in an optimum or reliable structural performance during service. The methodology is demonstrated through a case study that examines the buckling behaviour of a composite plate in the presence of manufacturing-induced imperfections. The intrinsic and extrinsic process parameters that affect the dimensional stability of more complex composite structures such as L- and C-shaped angular laminate sections, are numerically investigated using COMPRO. The predictive capability of COMPRO is examined by comparing the simulation results with available experimental measurements. Finally, to account for all sources of residual stress build-up required for accurate assessment of failure, the micro-level stresses arising from the mismatch between the coefficient of thermal expansions of the fibre and the matrix and the matrix cure shrinkage are computed through micromechanical finite element analysis of a representative volume of the fibre and the matrix. The ply- and laminate-level residual stresses computed by COMPRO during the curing process are then transferred to the micro-level using suitably derived stress magnification factors.
Item Metadata
Title |
Effect of processing on the behaviour of laminated composite structures : a numerical and probabilistic approach
|
Creator | |
Publisher |
University of British Columbia
|
Date Issued |
2002
|
Description |
The manufacturing of composite structures made of fibre-reinforced thermoset matrix materials
generally results in residual stress build-up during the curing process. As a consequence, the
precise geometry and material properties of the final structure after tool (mould) removal are
often difficult to control. To account for such process-induced variations, engineers either have
employed empirical knockdown factors, which are determined experimentally for a range of
distinct structures, materials and manufacturing processes or have incorporated the measured
variations as input into sophisticated finite element analyses. The first approach may lead to an
unconservative design while the second approach is not suitable for normal design practice.
In this study, a combined deterministic-stochastic simulation approach is presented to
demonstrate the manner in which manufacturing-induced variabilities in composite structures
can be controlled to achieve targeted reliability levels in structural performance. A finite element
code, COMPRO, which deterministically simulates the various physical phenomena during
manufacturing of composite structures, is integrated with non-linear structural analysis and
reliability analysis to compute the statistics of the parameters that must be controlled at the
manufacturing level in order to result in an optimum or reliable structural performance during
service. The methodology is demonstrated through a case study that examines the buckling
behaviour of a composite plate in the presence of manufacturing-induced imperfections.
The intrinsic and extrinsic process parameters that affect the dimensional stability of more
complex composite structures such as L- and C-shaped angular laminate sections, are
numerically investigated using COMPRO. The predictive capability of COMPRO is examined
by comparing the simulation results with available experimental measurements.
Finally, to account for all sources of residual stress build-up required for accurate assessment of
failure, the micro-level stresses arising from the mismatch between the coefficient of thermal
expansions of the fibre and the matrix and the matrix cure shrinkage are computed through
micromechanical finite element analysis of a representative volume of the fibre and the matrix.
The ply- and laminate-level residual stresses computed by COMPRO during the curing process
are then transferred to the micro-level using suitably derived stress magnification factors.
|
Extent |
14617682 bytes
|
Genre | |
Type | |
File Format |
application/pdf
|
Language |
eng
|
Date Available |
2009-08-06
|
Provider |
Vancouver : University of British Columbia Library
|
Rights |
For non-commercial purposes only, such as research, private study and education. Additional conditions apply, see Terms of Use https://open.library.ubc.ca/terms_of_use.
|
DOI |
10.14288/1.0063921
|
URI | |
Degree | |
Program | |
Affiliation | |
Degree Grantor |
University of British Columbia
|
Graduation Date |
2002-05
|
Campus | |
Scholarly Level |
Graduate
|
Aggregated Source Repository |
DSpace
|
Item Media
Item Citations and Data
Rights
For non-commercial purposes only, such as research, private study and education. Additional conditions apply, see Terms of Use https://open.library.ubc.ca/terms_of_use.