Performance Analysis of Full Assembly Glass Fiber-Reinforced Polymer Composite Cross-Arm in Transmission Tower

The Reduction Factor of Pultrude Glass Fibre-Reinforced Polyester Composite Cross-Arm: A Comparative Study on Mathematical Modelling for Life-Span Prediction

This paper presents an experimental and numerical investigation of pultruded composite glass fibre-reinforced polymer (pGFRP) cross-arms subjected to flexural creep behaviour to assess their performance and sustainability in composite cross-arm structure applications. The primary objective of this study was to investigate the failure creep behaviour of pGFRP cross-arms with different stacking sequences. Specifically, the study aimed to understand the variations in strain rate exhibited during different stages of the creep process. Therefore, this study emphasizes a simplified approach within the experiment, numerical analysis, and mathematical modelling of three different pGFRP composites to estimate the stiffness reduction factors that determine the prediction of failure. The findings show that Findley's power law and the Burger model projected very different strains and diverged noticeably outside the testing period. Findley's model estimated a minimal increase in total strain over 50 years, while the Burger model anticipated PS-1 and PS-2 composites would fail within about 11 and 33 years, respectively. The Burger model's forecasts might be more reasonable due to the harsh environment the cross-arms are expected to withstand. The endurance and long-term performance of composite materials used in overhead power transmission lines may be predicted mathematically, and this insight into material property factors can help with design and maintenance.

Creep Properties and Analysis of Cross Arms' Materials and Structures in Latticed Transmission Towers: Current Progress and Future Perspectives

Fibre-reinforced polymer (FRP) composites have been selected as an alternative to conventional wooden timber cross arms. The advantages of FRP composites include a high strength-to-weight ratio, lightweight, ease of production, as well as optimal mechanical performance. Since a non-conductive cross arm structure is exposed to constant loading for a very long time, creep is one of the main factors that cause structural failure. In this state, the structure experiences creep deformation, which can result in serviceability problems, stress redistribution, pre-stress loss, and the failure of structural elements. These issues can be resolved by assessing the creep trends and properties of the structure, which can forecast its serviceability and long-term mechanical performance. Hence, the principles, approaches, and characteristics of creep are used to comprehend and analyse the behaviour of wood and composite cantilever structures under long-term loads. The development of appropriate creep methods and approaches to non-conductive cross arm construction is given particular attention in this literature review, including suitable mitigation strategies such as sleeve installation, the addition of bracing systems, and the inclusion of cross arm beams in the core structure. Thus, this article delivers a state-of-the-art review of creep properties, as well as an analysis of non-conductive cross arm structures using experimental approaches. Additionally, this review highlights future developments and progress in cross arm studies.

Buckling Analysis of CNT-Reinforced Polymer Composite Beam Using Experimental and Analytical Methods

The aim of this article was to investigate the effect of carbon nanotubes (CNTs) on the buckling behavior of fiber-reinforced polymer (FRP) composites. The materials used included three layers: carbon-fiber-reinforced polymer (CFRP), epoxy and CNTs. A set of mechanical tests, such as compression and buckling tests, was performed, and also analytical solutions were developed. Damage analysis was also carried out by controlling the damage initiation and crack progression on the composite samples. Experimental results revealed that using 0.3% with CNT additives enhanced the buckling performance of the composite. Finally, the average load-carrying capacity for the clamped-clamped boundary condition was 268% higher in the CNT samples and 282% higher in the NEAT samples compared to the simple-simple condition.

Effect of Stacking Sequence on Long-Term Creep Performance of Pultruded GFRP Composites

Pultruded glass-fibre reinforced polymer (pGFRP) composites are classified as lightweight material, which exhibit high strength-to-weight ratio for structural usage. This composite material has been applied as cross-arm members in transmission towers due to its ability in thermal and electrical insulation. However, the influence of the stacking sequence of pGFRP composite on its mechanical performance has not been fully covered in the literature to explain the long-term durability of the current cross-arm designs. The study expected to evaluate five fiber layers with various stacking sequences in terms of quasi-static and creep tests in a four-point bending mode. The creep test was performed for 1440 h (60 days). These composites were fabricated using the pultrusion process in the form of a square hollow structure. Later, it was cut into composite coupons with various sizes depending on the test conducted. The results showed that nine layers with 0°/45°/0°/−45°/0°/−45°/0°/45°/0° had the ultimate flexural strength. This stacking sequence configurations seemed to be optimally manufactured in continuous roving fibre by alternating between 0° and ±45° fiber orientations. Additionally, the S-9 pGFRP composite sample showed that it had a low-creep deflection with high elastic and apparent creep moduli in 1440 h. In terms of strength reduction factor, this configuration was recorded as the highest. The findings showed that the nine layers of pGFRP composites with alternation of 0° and ±45° fiber orientations were highly suitable for structural application at transmission towers for a long-term operation.

Properties of Basalt Fiber Core Rods and Their Application in Composite Cross Arms of a Power Distribution Network

As basalt fiber has better mechanical properties and stability than glass fiber, cross arms made of continuous basalt-fiber-reinforced epoxy matrix composites are capable of meeting the mechanical requirements in the event of typhoons and broken lines in coastal areas, mountainous areas and other special areas. In this paper, continuous basalt-fiber-reinforced epoxy matrix composites were used to fabricate the core rods and composite cross arms. The results verified that basalt fiber composite cross arms can meet the strict requirements of transmission lines in terms of quality and reliability. In addition to high electrical insulation performance, the flexural modulus and the flexural strength of basalt fiber core rods are 1.8 and 1.06 times those of glass fiber core rods, respectively. Basalt fiber core rods were found to be much better load-bearing components compared to glass fiber core rods. However, the leakage current and the result of scanning electron microscopy (SEM) analysis reveal that the interface bonding strength between basalt fibers and the matrix resin is weak. A 3D reconstruction of micro-CT indicates that the volume of pores inside basalt fiber core rods accounts for 0.0048% of the total volume, which is greater than the 0.0042% of glass fiber rods. Therefore, improving the interface bond between basalt fibers and the resin can further improve the properties of basalt fiber core rods.

Development of Natural Fibre-Reinforced Polymer Composites Ballistic Helmet Using Concurrent Engineering Approach: A Brief Review

In this decade, all researchers and industry players compete to develop sustainable product design by exploring natural fibre composites in product design development. One of the essential methodologies in creating composite products is concurrent engineering (CE). Industrial design and production engineering should be involved in the development of ballistic helmets. This publication aims to provide a quick overview of the evolution of natural fibre composite ballistic helmet designs. This manuscript is still in its early stages, but it already includes a summary of the progress of ballistic helmet design from 1915 to the present. Renewable materials, such as natural fibre, should be highlighted as an alternative to synthetic composites in developing a sustainable ballistic helmet design. Furthermore, launching the design development process for a ballistic helmet demands a CE strategy that includes multi-disciplinary knowledge. Computational modelling aids in the development of ballistic helmet designs, reducing the time and cost of manufacturing ballistic helmets. The ergonomic component of ballistic helmet design is also crucial, as is the thermal comfort factor, which can be handled using natural fibre composites with thermal solid insulating characteristics. The development of natural fibre composite ballistic helmets can be used as a consideration in the future as a revolution to create a sustainable design. Finally, this review can be used as a guide for industrial designers. In conclusion, this review might be utilized as a reference for industrial designers due to a shortage of studies, especially in producing product-related natural fibre.