Hybrid Aluminum and Natural Fiber Composite Structure for Crash Safety Improvement

Helaili, Sofiene; Chafra, Moez; Chevalier, Y.

doi:10.1007/978-3-319-48766-3_25

Cited by 12 publications

(6 citation statements)

References 7 publications

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“…Composite materials, which are composed of a combination of different types of fibers, have a wide range of applications in various fields, such as crash and safety [1], [2], civil engineering [3]- [5], and biomechanics [6]- [8]. Researchers in Tunisia have been investigating using natural fibers [9]- [14], including palm [15] and cellulosic fibers [16]- [18], in composite materials to utilize local resources and promote sustainability.…”

Section: Introductionmentioning

confidence: 99%

The Viscoelastic Comportment of Composite Plates Reinforced with Synthetic and Natural Alfa (Stipa tenacissima L.) Fibers for Structural Applications

Helaili¹,

Belbachir²,

Khadimallah³

2023

cea

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Composite materials are widely used in applications subjected to low, medium, and high loading frequencies. The viscoelastic behavior of these materials can significantly impact their performance and behavior under different loading conditions. As a result, it is important to carefully study the viscoelastic behavior of composite materials to design structures that can effectively withstand vibration or time-varying loads. This study investigated the static elastic, vibratory, and viscoelastic behavior of composite materials made from Carbon/Epoxy and PMMA/Natural Alfa fibers using both analytical and numerical approaches. The laminates studied included an asymmetrical laminate and an antisymmetrical laminate, both with a thickness of 2mm and composed of 9 plies. Stresses and strains were calculated for each ply and the overall composite plate. The study showed that the numerical finite element models produced results that agreed with the analytical models. The modal analysis revealed that the first frequency of the symmetrical composite [0/+45/-45/60/0/60/-45/+45/0] was 4.16Hz, which was higher than the first frequency of the antisymmetrical composite (2.61Hz) made from Carbon/Epoxy60% fibers. In terms of the viscoelastic behavior, the relaxation test of a 2mm plate showed that the stresses in the Carbon/Epoxy60% composite were stabilized quickly, while it took 20 minutes for the stresses of Alfa/PMMA45% composite plates. Alfa/PMMA45% can be a candidate for civil applications.

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Section: Introductionmentioning

confidence: 99%

The Viscoelastic Comportment of Composite Plates Reinforced with Synthetic and Natural Alfa (Stipa tenacissima L.) Fibers for Structural Applications

Helaili¹,

Belbachir²,

Khadimallah³

2023

cea

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“…The reinforcement with Alfa fibers improves the rubber composite properties such as breaking strength and elongation at break. Applications of natural fibers composites have spread to automotive [16] and biomechanics [17] as well. However, the use of this plant in the construction field is recent [18], and many studies tried to better understand the behavior of this plant and natural fibers in general in cement mortars mixtures [19].…”

Section: Introductionmentioning

confidence: 99%

Natural Cellulosic Alfa fiber improved with environment-friendly treatment cementitious composites with a stable flexural strength

Helaili

guizani

Chafra

2022

Preprint

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Using natural fibers in structural applications is the subject of much research in the scientific world. Natural fibers are bio-sourced, biodegradable, have a low carbon footprint, and have interesting mechanical properties. The lightness, tensile strength, and elongation before break make natural fibers suitable candidates to replace synthetic fibers. Sometimes, natural fibers must undergo heavy chemical treatment for the extraction of microfiber. This is not the case in this paper, which presents a first attempt to use esparto fiber in its raw state without heavy treatment without soda and bleach. In this paper, the raw esparto stem cut into short fibers is treated, then prepared and used as reinforcement in mortar. The mechanical properties of the esparto stems were identified, analyzed, and improved. The mechanical tests showed a weak adhesion between the mortar and Alfa. Also, excessive absorption of water by the stem induced a delay in the mortar's setting. Even with unsaturated stems, this phenomenon is observable. An improvement was applied to the natural Alfa stem to improve its adhesion and reduce the absorption of spillage water. For the first time, as a major innovation in natural fibers used for cementitious composites, a method is presented in this paper allowing the use of Alfa (esparto) fiber in a mortar while keeping the mechanical strength properties of the mortar. Test specimens 4x4x16 cm were made and reinforced with short fibers of 2 and 3 cm with different volume concentrations: 1%, 2%, and 5%. The flexural strength and compressive strength were determined experimentally. The results show that for the 1% concentration of short fibers of 3cm, the compressive strength is 26 MPa, which is almost identical to the strength of the control specimen equal to 26.03 MPa. Flexural strength of the improved fibers concentrated at 1%, 2%, and 5% reach nearly 4.75 MPa very close to the flexural strength of the control specimen, which is 5.57 MPa. The flexural strength doesn't decrease with treated Alfa fiber concentration increase: this is a unique case in which flexural strength doesn't decrease compared to other natural fibers results in the literature. In a conclusion, Alfa-treated short fibers can be used in secondary structural applications subject to compressive and light bending forces, for example, paving applications.

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“…The use of composites is increasing in the construction [1][2][3] sector for repair 4 and strengthening 5,6 work. Composites have been used in the aeronautical industry, 7 automotive, [8][9][10] and biomechanics. 11,12 The benefit of composites is that they can have complex shapes and can be manufactured to withstand heterogeneous and aggressive media, as well as heavy loads.…”

Section: Introductionmentioning

confidence: 99%

Identification of mechanical properties of a braided alfa stem (Stipa tenacissima L.) by an inverse method

Helaili

Chafra

2022

Journal of Composite Materials

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The aging of buildings and structures, accompanied by an increase in the prices of conventional building materials, has pushed the scientific community to explore new techniques and materials to rehabilitate existing buildings. Rehabilitation aims to extend the service life of a structure while maintaining its strength and stability. Among these techniques, composite materials based on synthetic fibers, such as carbon fibers, have been developed. However, materials with low carbon footprints that are bio-sourced and eco-friendly are of interest to the scientific community. The use of Alfa plant natural stems in a braided form is the focus of this study. This study is the first to use geometric shapes to improve the performance of a natural fiber-reinforced composite. Epoxy was used as the matrix, which is the material used most often in composite designed for reinforced concrete structures. This study aims to determine the equivalent mechanical properties of the Alfa braided stem using the reverse method. Test specimens of the epoxy/Alfa composites were manufactured and tested on a tensile machine. The epoxy was tested, and its properties were determined. Subsequently, a finite element numerical model of the specimen was constructed, and the properties of the braided Alfa stem were varied until identical results were obtained. The mechanical properties of the Alfa braided stem were thus identified. The results showed that the braided Alfa stem had a stiffness modulus of 23.243 GPa.

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Hybrid Aluminum and Natural Fiber Composite Structure for Crash Safety Improvement

Cited by 12 publications

References 7 publications

The Viscoelastic Comportment of Composite Plates Reinforced with Synthetic and Natural Alfa (Stipa tenacissima L.) Fibers for Structural Applications

The Viscoelastic Comportment of Composite Plates Reinforced with Synthetic and Natural Alfa (Stipa tenacissima L.) Fibers for Structural Applications

Natural Cellulosic Alfa fiber improved with environment-friendly treatment cementitious composites with a stable flexural strength

Identification of mechanical properties of a braided alfa stem (Stipa tenacissima L.) by an inverse method

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