Papers by Keyword: Thermo-Mechanical Properties

Abstract: Carbon fiber–reinforced polymer (CFRP) composites are extensively used in aerospace applications; however, their end-of-life management remains a critical challenge. This study investigates an unconventional recycling route based on the direct hot compression molding of CFRP waste powders, aiming to valorize industrial composite scraps without the addition of virgin polymers or binding agents. The material investigated corresponds to the finest fraction (~300 μm) obtained from a sieving process applied to industrial CFRP scrap powders derived from trimming residues and partially cured aeronautical prepregs. The use of this fine powder fraction promotes effective particle aggregation and consolidation during molding, preventing powder loss during demolding and enabling the fabrication of relatively thick panels despite the absence of additional bonding agents. Compression molding was carried out at 250 °C and 1.5 bar for 20 min. Two material configurations were analyzed: uncoated compression-molded panels and panels coated with a thin polyester layer. The recycled materials were characterized through morphological, thermomechanical, and mechanical analyses. The results indicate that the polyester-coated panels exhibit improved mechanical performance compared to the uncoated configuration. In comparison with previous studies focused on coarser powder fractions (≤1 mm), the present work highlights the potential of the finest powder fraction for effective consolidation, demonstrating the strong influence of particle size on the processability and properties of compression-molded recycled CFRP. These findings confirm the viability of direct compression molding as a sustainable and scalable recycling strategy for tailoring CFRP waste reuse as a function of powder size.

Abstract: This paper uses a sequential micromechanical method to characterize the thermomechanical properties of a hybrid nanocomposite. It does this by using analytical models (such as the modified rule of mixtures, Tsai-Pagano model, and Schapery model) and numerical models (such as the Finite element model), which are modeled using the commercial software ABAQUS. Investigations are made to determine how the aspect ratio, waviness, and volume fractions of the reinforcement affect the thermo-mechanical performance of the hybrid nanocomposite. It has been shown that adding CNT ESFs to conventional SiC-reinforced titanium alloy composites (TMCs) improves the resulting HTMNC thermo-mechanical properties. It is found that the addition of CNT ESFs to TMCs improves the thermo-mechanical characteristics of the resulting hybrid nanocomposite (i.e., HTMNCs) more in the transverse direction than in the axial direction for all volume fractions of SiC fiber. For instance, it is observed that adding a 2.69% volume fraction of CNT ESFs to the TMCs with a 30% volume fraction of SiC fiber enhances the axial elastic modulus by 2.6% and 2.4% while increasing the transverse elastic modulus by 4.2% and 3.5%, based on the CNT ESFs are straight and wavy. On the other hand, for the same volume fraction of SiC fiber and the addition of 2.69% volume fraction of Straight CNT ESFs, the transverse and axial CTE of the HTMNCs are reduced by 5.33% and 2.53%, respectively. Moreover, when the SiC fiber aspect ratio increases, the axial elastic modulus increases while the transverse elastic modulus exhibits no change. In contrast to the elastic modulus, the CTE increases in the transverse direction while decreasing in the axial direction.

Abstract: Special protective clothing is used to protect people in critically low temperatures. It exposed not only by temperature, but also by the effects of wind and the movements of the person. These aerodynamic and mechanical influences compress certain areas that return to their original position only after a certain period of time. However, during this interval the thermal resistance of the compressed part of the clothing decreases. In order to avoid such a situation, material packages have been developed to increase their elasticity. This article proposes a new material package design using a thermo-elastic element which, when the temperature changes to the required temperature, changes its shape. The article proposes the placement of the thermoelastic element, as well as a technique in which the thermoelastic element acquires the property of memorizing its shape at a certain temperature. Titanium nickelide alloy NiTi (nitinol) is used as a thermoelastic element. According to the method proposed in the article, this alloy remembers the shape at a temperature of +20°C (straight) and-18°C (bending). Thus, when the nitinol wire responses at negative temperature, the bend is manifested and the wire lifts the fabric of the top, thereby increasing the volume of the material package, which allows the insulation to occupy a larger volume increasing the thermal resistance of the package.

Abstract: The attractiveness of glass is something that occupied the world market with a unique claim. It has many applications that go beyond the provision of visual aesthetics, which includes a view of the inside and out. Due to extreme levels of clarity, structural glazing may be so transparent that it may go unnoticed by design or make a strong visual impact such as the focal point of a building. This paper focused on structural glass with various laminated/laminated conditions that were used to investigate the Dynamic Mechanical Properties. The storage modulus (G'), loss modulus (G'') and damping factor (tan delta) were determined at various levels, ranging from room temperature to elevated temperatures (250 °C) to understand the behavior of glass structure with and without laminated glass over a range of temperatures. The G' & G'' were tested to understand the effect of bonding, fracture behavior between the pure glass and laminated glass to observe the response with respect to temperature. Results are found that G' and G'' improve over a range of temperatures for laminated glass with enlightening fracture behavior. Laminated glass also has a major influence on the damping factor, but it also depends on the laminated thickness and materials. Thermo-Mechanical Properties of laminated glass are more improved, without affecting the transferability of glass.

Abstract: Fused Deposition Modelling (FDM) technology is one of most common technique used in 3D printing as of today for several reasons such as it is low cost and high speed printing capacity. However, common characteristic of FDM 3D printed materials are poor layer adhesion strength and rough surface finish which requires post-processing to improve it. Heat treatment and vapor-polishing are post-processing techniques used to address the poor layer adhesion and rough surface finish of 3D printed materials, respectively. This study will combine these two post-processing techniques and investigate its effect on the mechanical properties of 3D printed materials. The present study describes the effect of acetone vapor-polishing to facture behavior of ABS 3D printed material at higher operating temperatures. The study will compare the fracture behavior of ABS 3D-printed material when polished using acetone vapor bath and tested at high operating temperature to unpolished material. Five replications for each test condition were conducted. All experiment was carried out using ASTM Izod Type E tests with a 2.75J pendulum. The results showed that acetone vapor polishing strongly affects the fracture behavior of ABS 3D printed materials when operating at high temperature.

Abstract: The objective of this research is to evaluate the temperature dependent strengthening mechanism of 0.5 wt.% carbon nanofiber reinforced glass fiber/epoxy (CNF-GE) as a function of environmental temperature. Flexural response of the CNF-GE composite has been studied at 30°C, 70°C and 110°C temperatures and compared over control glass fiber/epoxy (GE) composite. When flexural test was conducted at room temperature, CNF-GE composite exhibited about 29% improvement in strength, over control GE composite. With increase in environmental temperature, the extent of strength enhancement continued to decrease and at 110°C, the strength of the CNF-GE composite was found to be about 12% lower than control GE composite. Visco-elastic properties of CNF-GE and control GE composites have also been studied in the temperature range of 40 to 200°C.

Abstract: The main objective of this study is to investigate the thermo-mechanical properties of composite made from geopolymer/carbon fiber/TiO₂ NPs. The composite was fabricated from geopolymer based on metakaolin added with carbon fibers as reinforcement and TiO₂ NPs as self-cleaning agent. The thermal properties of the composite was examined by subjecting the samples to temperature up to 750^OC for 4 hours. The mechanical properties of the resulting materials were measured by using flexural and tensile strength measurements. The experimental results showed that the compsite exhibited high temperature resistance and the addition of carbon fiber were increase the flexural as well as the tensile strength of the composite.

Abstract: The possibility of creating polymeric nanocomposites with desired properties can be achieved by mixing it with an appropriate nanomaterial. The carbon-based nanomaterials have an excellent combination of both physical and chemical properties which create a significant interest among the researchers to prepare an industrially useful material employing carbon based nanomaterials as the filler. The thermo-mechanical properties of materials are studied to characterize their internal state and structure. In this chapter, the thermomechanical properties of polymer-CNT nanocomposites and the various factors affecting the thermomechanical properties are discussed.

Abstract: This chapter reviews recent development of graphene-based polymer composites. The formation of graphene oxide and graphene are a vital two dimensional (2D) material has received a lot of research interest in commercialization aspect due to its excellent electrical, thermal as well as mechanical properties at very low filler content. In this manner, utilization of graphene-based polymer composites with different polymer matrixes have been attracted increasing attention in recent years for both fundamental studies and applied research into industrial applications in many fields. Herein, novel properties of polymer (epoxy, polystyrene, and PANI) / graphene composites will be reviewed along with detailed examples drawn from the scientific literature. Keywords: Graphene-based polymer composites, thermo-mechanical properties, two dimensional (2D) materials

Abstract: In this chapter, bamboo fiber with parallel and anti parallel orientation has been introduced in the Unsaturated polyester (UPE)/ Epoxidized Soybean Oil Acrylate (ESOA) blend. The reinforced fiber mats were treated with NaOH and NaOH-silane to improve the stiffness and strength of the composites. Parallelly oriented fiber reinforced composite showed improved glass transition temperature. The mechanical, thermal, storage modulus and tribological properties are highly improved for parallel fiber oriented composite. Also alkali-silane treated fiber reinforced composite show optimum properties than alkali treated and raw fiber based composites. Anti parallelly oriented composites show reduced performance due to pull out of fibers. The FTIR analysis of all the composites was observed for the first time with valid reaction mechanism. So this new partially biodegradable composite can open a new door for potential application in various fields. This composite may be used as an alternating material to wood for various indoor and outdoor applications.