Numerical and Experimental Analyses of Hybrid Composites Made from Amazonian Natural Fibers

The application of lignocellulosic fibers as reinforcements in composite materials has found increasing use in recent years, due to the attractive characteristics of natural fibers such as their low cost, high specific modulus, biodegradability, abundance and with many technical qualities. Natural fiber hybrid composites are very frequently used in automotive aerospace and other industries. In this work, numerical and experimental analysis is carried out to compare curauá, jute and sisal fibers in epoxy composites for use in industry. The most appropriate hybridization effect by establishing the amounts of each fiber on the mechanical properties was considered. Finite Element Models were designed and validated through mechanical tests. The number of Finite Element models and specimens performed was determined through the design of experiments using the Taguchi Method and then the results were statistically validated. Higher strength was obtained in composites made with curauá fiber, followed by jute and sisal fibers. Such behavior was achieved by FEM and experimental tests, revealing an increase in tensile strength by increasing the amount of fibers up to 35% in total. Higher strength was achieved when the composite was made with curauá (20 wt.%), jute (10 wt.%) and sisal (5 wt.%) fibers. The results show a good agreement between the FEM and the experimental tests. Furthermore, the results of the present study were compared with those obtained previously mentioned in the open literature

Mechanical characterization of mortar reinforced by date palm mesh fibers: Experimental and statistical analysis

International audienceAs part of local agricultural date palm waste valorization, this work describes bio-composites made with a cement matrix reinforced with short Mesh date palm fibers for non-structural civil engineering applications. The study focuses in particular on investigating the influence of four parameters on the bending and compression properties of the bio-fiber reinforced mortar: the fiber content, length, NaOH concentration and immersion times of those fibers in the chemical solution. For this purpose, flexural and compression tests have been carried out. An experimental design representing 27 combinations of the above four parameters has been established to minimize the number of experimental trials and build a surface response methodology (SRM) using the design expert software 12 code. The results obtained show that the incorporation of mesh date palm fibers into the mortar improve the mechanical properties of the bio-fiber reinforced mortar. The bending stress of beams with the bio-based reinforcement increases 27.5% compared to the reference configuration; the bending modulus conversely improves by 18.9%. Compression stress and modulus showed increases around 46.6% and 36.3%, respectively. The objective function used to optimize the mechanical properties provides however an increase in bending stress and modulus around 50.0% and 20.0%, respectively, compared to the reference mortar case. The parametric design of the bio-composites that provided the best compression performance was very close to the one identified by the minimum of the objective function. Confirmatory experimental tests results compared to those from the objective function model developed show good agreement, with 3.3% and 3.8% differences for the bending stress and modulus, respectively

Alkali Treatment Effect on Physicochemical and Tensile Properties of Date Palm Rachis Fibers

This work aims to optimize the physicochemical and tensile properties of vascular fibers extracted from a local date palm rachis in Algeria. This fiber has a very specific composition and architecture and is different from the remaining fibers obtained from the six possible parts of the tree. For this purpose, a Taguchi orthogonal array design L16 was applied to reduce the number of experiments. The fibers were extracted from the rachis with two different methods (boiling and retting in water) and treated by NaOH with various concentrations (1%, 2%, 3%, and 5%) and for different durations (1, 4, 8, and 12 h). They were characterized using SEM-EDX, ATR-FTIR, XRD, and TGA to understand the effects of the extraction method and alkali treatment. A statistical treatment of the data was carried out based on the S/N ratio and ANOVA was performed to identify the most significant parameters affecting the tensile strength and the Young’s modulus of the fibers. A desirability function was developed to identify the optimal factors leading to the maximization of the tensile properties