Experimental investigation of compressive properties & evaluation of failure modes in FRP compositesI) ABSTRACT: Composite construction is of particular interest and widely used, because the concept is very suitable and amenable to the development of lightweight structures with high in-plane and flexural stiffness. Composite panels consist typically of two or more constituents, which are soluble in each other. The overall performance of composite structures depends on the material properties of the constituents (facings, adhesive, and core), geometric dimensions and type of loading. Composite panels under compression and in-plane loading display various failure modes. Failure modes and their initiation can be predicted by conducting a thorough stress analysis and applying appropriate failure criteria in the critical regions of the panels including three-dimensional effects. This analysis is difficult because of the nonlinear and inelastic behavior of the constituent materials and the complex interactions of failure modes. For this reason, properly designed and carefully conducted experiments are important in elucidating the physical phenomena and helping the analysis.In the present work, an experimental investigation will be conducted on failure modes during compressive load for their occurrence in composite specimens. The initiation of the various failure modes depends on the material properties of the constituents, geometric dimensions, and type of loading. The loading type or condition determines the state of stress throughout the composite structure, which controls the location and mode of failure. The specimens will be made of bi-woven glass epoxy and graphite–epoxy laminates. The failure envelopes were developed for general two-dimensional states of stress. Composite specimens will be loaded under compression & failure modes will be observed and compared with available literature. The failure modes to be investigated are compressive failure, adhesive bond failure, indentation failure, and facing wrinkling. The compressive strength & compressive modulus will also be estimated for both types of composite specimens. The transition from one failure mode to another for varying loading or state of stress will be discussed. Experimental results obtained will be correlated with analytical predictions.KEY WORDS: Composite structures, failure modes, face wrinkling, debondingII) ObjectivesThe primary objectives are• To prepare composite specimens with different fibers.• To perform compression test in determining the compressive strength and compression modulus.• To assess the failure modes of composite laminates due to compression.• Design changes can also be evaluated by using compressive strength and compression modulus.• To evaluate the compressive properties for different composite specimens which are very vital for various design applications.III) Methodologya) Literature Surveyb) Preparation of Laminates with different fibers.c) Compression testing of composite laminates as per ASTM Standardsd) Evaluation compressive properties.e) Interpretation of the resultsf) Conclusions.IV) References1. ASTM D3410 / D3410M - 03(2008) Standard Test Method for Compressive Properties of Polymer Matrix Composite Materials with Unsupported Gage Section by Shear Loading.2. S.J. Kim and S.H. Chang, “The relation between compressive strength of carbon/epoxy fabrics and micro-tow geometry with various bias angles”, Structures Volume, September 2006, Pages 400-4073. N. K. Naik, and R. Ramasimha, “Estimation of compressive strength of delaminated composites”, Composite Structures Volume 52, Issue 2, May 2001, Pages 199-204.4. Yasuhide Shindo, , Hitoshi Tokairin et.al, “Compression behavior of glass-cloth/epoxy laminates at cryogenic temperatures”, Cryogenics Volume 39, Issue 10, 12 October 1999, Pages 821-827 5. M. F. S. F. de Moura, et.al, “Prediction of compres
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Experimental investigation of compressive properties &
evaluation of failure modes in FRP composites ByRavi kumar
Rharanappa koodi
Objectives
To prepare composite specimens with different fibers.
To perform compression test in determining the compressive
strength and compression modulus.
To assess the failure modes of composite laminates due to
compression.
Design changes can also be evaluated by using compressive
strength and compression modulus.
To evaluate the compressive properties for different composite
specimens which are very vital for various design applications.
Preparation of specimen by HAND LAY-UP process
Specimen used and dimensionsBi-woven glass epoxy
laminatesGraphite epoxy laminatesDimensions and thickness of cut
and orientation150*150mm2mm and 4 mm0 and 90 degree
Mode of failuresInitiation of the various failure modes depends
on 1.The material properties of the constituents 2.Geometric
dimensions, 3.Type of loading. The loading type or condition
determines the state of stress throughout the composite structure,
which controls the location and mode of failure
Loading type failureThe loading type or condition determines the
state of stress throughout the composite structure, which controls
the location and mode of failureFailure envelopes were developed
for general two-dimensional states of stress The failure modes to
be investigated are compressive failure, adhesive bond failure,
indentation failure, and facing wrinkling
FEM analysisWe determine the compressive properties of the FRP
composite by using ANSYIS and FEM PRO.
ApplicationsAutomobile sectorConstruction fieldMedical
fieldRecreationMarine fieldSports goodsElectrical and electronic
industries
Methodology
a) Literature Surveyb) Preparation of Laminates with different
fibers.c) Compression testing of composite laminates as per ASTM
Standardsd) Evaluation compressive properties.e) Interpretation of
the resultsf) Conclusions.
References1. ASTM D3410 / D3410M - 03(2008) Standard Test Method
for Compressive Properties of Polymer Matrix Composite Materials
with Unsupported Gage Section by Shear Loading.
2. S.J. Kim and S.H. Chang, The relation between compressive
strength of carbon/epoxy fabrics and micro-tow geometry with
various bias angles, Structures Volume, September 2006, Pages
400-407 3. N. K. Naik, and R. Ramasimha, Estimation of compressive
strength of delaminated composites, Composite Structures Volume 52,
Issue 2, May 2001, Pages 199-204.
4. Yasuhide Shindo, , Hitoshi Tokairin et.al, Compression
behavior of glass-cloth/epoxy laminates at cryogenic temperatures,
Cryogenics Volume 39, Issue 10, 12 October 1999, Pages 821-827
5. M. F. S. F. de Moura, et.al, Prediction of compressive
strength of carbonepoxy laminates containing delamination by using
a mixed-mode damage model, Composite Structures Volume 50, Issue 2,
October 2000, Pages 151-157. under your organization's agreement
with Elsevier.
