Composite Materials Research Progress

144
Material
Yuanxin Zhou, Hassan Mahfuz, Vijaya Rangari et al.
Table 2. Flexure test data for carbon prepreg laminates
Flexural
Strength
(MPa)
Average
Strength
(MPa)
Gain/Loss
Strength
(%)
Flexural
Modulus
(GPa)
Neat Sample 1 765.32 82.14
Neat Sample 2 806.46 80.43
Neat Sample 3 789.38 787.45 -- 82.05
Neat Sample 4 782.62 80.29
Neat Sample 5 793.45
76.91
1.5wt% Sample1 1043.35 93.93
1.5wt% Sample2 995.28 97.02
1.5wt% Sample3 1012.59 1042.34 +32.37 98.25
1.5wt% Sample4 1088.92 90.65
1.5wt% Sample5 1071.55
99.36
Average
Modulus
(GPa)
80.36 --
Gain/Loss
Modulus
(%)
95.84 +19.26
Table 3. Standard deviation and Coefficient of variation of flexure test data
Standard Deviation (±) Co-eff. of Variation (%)
Neat system Strength 13.52 1.72
Neat system Modulus 1.89 2.36
+1.5wt% Nano-phased system Strength 34.99 3.36
+1.5wt% Nano-phased system Modulus 3.17 3.31
Tensile Response of Layered Composites
Typical curves for the tensile behavior of both neat and 1.5 wt.% nano-phased specimen are
shown in Figure 17. The in-plane tensile behavior of both the composites shows linear
behavior up to approximately 1.2% strain where initial fiber failure occurred. The behavior
continued to be linear again till the final specimen failure. Both the elastic modulus and the
strength of nano-phased composites were between 7-10% higher than their neat counterparts.
The reason for such small improvement could be visualized in the sense that, in tension the
fiber took maximum load and the nanoparticle infusion in the matrix did not contribute much
in improving the tensile properties. The improvement of modulus in this study was mainly
because of the improvement of the matrix modulus by filler dispersion. Therefore it can be
deduced that higher tensile properties in the nanocomposite is due to higher nano-phased
matrix properties. Average mechanical properties and their deviation are shown in Table 4
and Table 5, respectively.