Effect of Number of Tests on the Mechanical Characteristics of Agave sisalana Yarns for Composites Structures: Statistical Approach

Abstract

A designer of sustainable biocomposite structures and natural ropes needs to have a high confidence interval (95% CI) for mechanical characteristics data of performance materials, yet qualities for plant-based fibers are very diverse. A comprehensive study of the elements that enhance the performance of biocomposites or sustainable ropes created from vegetable fibers is necessary. The current study included five groups with varying numbers (N) of tests of 20, 40, 60, 80, and 100 on the mechanical characteristics at room temperatures. The purpose of this study was to determine how changing N affects the mechanical properties of sisal yarn. These properties include its strength, Young’s modulus, and deformation at rupture. A significance testing program including more than 100 tests was performed. Owing to the heterogeneity of the plant yarn, each group received more than 20 samples at a gauge length (GL) of 100 mm. The tensile strength characteristics of sisal yarns produced a wide range of findings, as is common for natural fibers, necessitating a statistical analysis. Its dispersion was explored and measured using the statistical methods. The Weibull distribution with two parameters and a prediction model with a 95% confidence level for maximum likelihood (ML) and least squares (LS) were used to investigate and quantify its dispersion.

Mechanical properties and statistical analysis of Syagrus Romanzoffiana palm cellulose fibers

“…A similar behavior has been seen in the case of Washingtonia Filifera fibers presented by Dembri et al, 6 as well as jute fibers according to Wang et al 38 and Saidia et al 34 at a GL of 50 mm and sisal fibers studied by Belaadi et al 33 at different GLs and Gahgah et al at a GL of 100 mm. 36

Figure 4.Curve of stress-strain: (a) Tests on 30 specimens and (b) Behavior of SR fiber during tensile test.

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“…Figure 6(a) shows that Young’s modulus increases with increasing tensile strength, but decreases with increasing strain at break (Figure 6(b)). 33,36

Figure 6.Scatter plots for 200 tests of SR fibers for (a) tensile strength versus modulus of elasticity and (b) failure strain versus modulus of elasticity.

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“…A similar behavior has been seen in the case of Washingtonia Filifera fibers presented by Dembri et al, 6 as well as jute fibers according to Wang et al 38 and Saidia et al 34 at a GL of 50 mm and sisal fibers studied by Belaadi et al 33 at different GLs and Gahgah et al at a GL of 100 mm. 36 The usual behavior of the tensile curve for Syagrus Romanzoffiana fibers may be divided into two regions, as shown in Figure 4(b): The initial quasi-linear region at the beginning of the curve is the total fiber load and the free redirection of the fibrils in the direction of the tension. Furthermore, Belaadi et al 35 have described this occurrence.…”

“…Figure 6(a) shows that Young's modulus increases with increasing tensile strength, but decreases with increasing strain at break (Figure 6(b)). 33,36 According to the sample number, boxplots or Tukey boxes were plotted to show variation in typical SR fiber tensile strength, Young's modulus and break strain (Figure 7). The box plots were designed to display trends in a group's responses.…”

“…The association between WF yarn properties and trial count was emphasized by a one-way ANOVA. The influence of various test numbers ( N ) on mechanical properties for sisal yarn at ambient temperature was investigated in a recent study by Gahgah et al 36 Sisal yarn tensile strength decreased from 148 MPa to 138 MPa when N grew from 20 to 80 mm, eventually settling at 135 MPa at N = 100. The strain also decreased from 8.41% to 7.15% to 6.70% when N = 100 was used.…”