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Abstract:
Significance of the Proposed Work:
Continuous development of FRP materials in various forms and
configurations using affordable fabrication techniques offers
an alternative design approach for structural elements and present
new challenges to researchers and engineers. In the past few
years, various FRP composite panels have been implemented in
highway and pedestrian bridge construction. Light-weight, excellent
corrosion characteristics and rapid installation capabilities
created tremendous opportunities for FRP composite panels in
transportation industry. World wide, there are many completed
or currently underway applications using FRP composite panels
in civil infrastructure. Nevertheless, proper characterization
methods and generally accepted design and analysis procedures
for FRP composite panels have not been established. Technical
difficulties during fabrication, lack of comprehensive analysis
and design guidelines limit the full utilization of these materials.
The proposed research introduces new generation of FRP composite
panels produced by Martin Marietta Composites, USA. The research
aims to develop a general structural analysis methodology for
FRP sandwich panels. Structural behavior, strength and stiffness
characteristics of various FRP panels will be investigated both
experimentally and analytically. Design guidelines for the use
of FRP sandwich panels in transportation Infrastructure will
be provided.
Objectives
and Scope of Work:
The primary objective of the proposed research is to study
and examine the structural performance of innovative FRP sandwich
panels produced by Martin Marietta Composites, USA. The panels
consist of top and bottom skin GFRP layers connected together
using through-thickness fibers (Z-tows). Failure modes and
mechanisms will be investigated through a comprehensive experimental
program. Stiffness and strength analysis methodologies will
be established and complete set of design guidelines will
be provided. The test setup for various FRP panels under different
loading conditions is shown in Figures 1, 2 and 3.
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Figure
1. Test setup for FRP sandwich panels using a
concentrated truck tire loading at mid-span
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Figure
2. Test setup for FRP sandwich panels using two line
loads
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Figure
3. Test setup for FRP sandwich panels using one line
load at mid-span
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Research
Plan:
The experimental program includes two phases. Fundamental
material properties in tension, compression and shear will
be evaluated in the first phase of the experimental program.
The second phase will focus on the overall panel behavior
under various loading conditions. The analytical phase will
attempt to propose a ply-level analysis philosophy and will
provide general procedures for strength and failure analysis
of FRP sandwich panels. The flexural, one-way and two-way
shear behavior of FRP sandwich panels will be investigated.
The main variables in this study will include the thickness
of the panel, number of GFRP plies in the top and bottom skin
layers, intensity of vertical pins and type of loading. The
behavior of the panels during testing will be monitored using
a combination of electrical strain gauges, string potentiometers
and PI gauges.
Impact
to the State of Practice:
The proposed study will provide a significant contribution
to the current knowledge with regard to the behavior and analysis
procedures for FRP sandwich panels. Findings of the research
will assist in developing reliable design procedures for the
practical use of FRP composite sandwich panels in numerous
structural applications under different loading conditions.
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