Comparative studies of experimental and numerical evaluation of tensile properties of Glass Fibre Reinforced Polyester (GFRP) matrix

The investigation and comparative analysis of Chopped Strand Mat Glass Fibre Reinforced Polyester (CSMGFRP) composite laminates was conducted. The laminate samples for the experiment were first exposed to diverse X-rays intensity rates at 6 mAs interval before test under cryogenic temperature. The generated values for tensile properties like young's modulus, strength, force, energy and elongation values were all measured and noted. The tensile modulus presented 43.8% decrease at the first 12 mAs exposure before it started increasing in the order of 30.3%, 6.3% and 12.3% respectively. Also, a science laboratory (SciLab) numerical evaluation of the material's tensile young's modulus was carried out and the obtained values compared with the experimental result to ascertain the level of relationship between the two approaches. It was observed that all the tested tensile properties were not consistent in the line of material strength depreciation values, apart from tensile young's modulus. The latter is consistent, but when considered with numerical model; their values became inconsistent like the former. However, when Analysis of Variance (ANOVA) for both approaches (experimental and SciLab numerical evaluations) were checked using t-test for pair comparisons, the data sets produced a computed t-value of 4.51. The obtained t-value and the critical t-value of 2.57 for 5% level of significance and 5-degree of freedom were compared, and it was noticed that the obtained t-value was higher than the critical t-value which indicated that the result was significant at the 5% level. Thus the null hypothesis is rejected which suggests that both approaches were relevant to tensile properties investigation at cryogenic temperature.