Journal of Engineering & Technological Advances

EXPERIMENTAL INVESTIGATION ON THE INFLUENCE OF LATERAL EARTH PRESSURES ON RETAINING WALLS

2024-07-05T23:29:51+08:00

Despite continual advancement in retaining wall technology, failures of these structures still frequently make national news. In tropical countries like Malaysia, rainfall-induced landslides are a primary cause of these failures. Bridging the gaps in the Sustainable Development Goals (SDGs) of Sustainable Cities and Communities (SDG11), this study offers valuable insights to the importance of lateral earth pressure and its effects on retaining walls, therefore fostering the development of resilient infrastructure for the future. By focusing on prototype development and software simulations, this study investigates the failure mechanisms of an L-shaped cantilever retaining wall influenced by different groundwater table profiles, with a constant surcharge atop the backfill soil. The results indicate that the higher water tables correlate with lower factor of safety (FOS) and increased wall deformation. The results obtained using both software and prototype modelling shows FOS of sliding, overturning, and bearing capacity failure did not satisfy the requirement set by authorities due to the overloading and insufficient design of the geometry of the wall. These findings provide practical implications and are consistent with existing literature. Thus, this study provides an easy yet solid methodology to research on lateral earth pressures for future endeavours.

METALLURGICAL FAILURE ANALYSIS OF A TRICYCLE FRONT WHEEL AXLE

2024-09-09T11:39:22+08:00

Due to the rampant failure of the tricycle front wheel axle in Nigeria, the failure analysis of a tricycle front wheel axle was conducted in this work. The failed front wheel axle of the tricycle part was obtained. Chemical composition, microhardness and microstructures through metallography and SEM were performed. The results show the carbon content of the failed axle wheel (0.354 wt% C) is below standard. The hardness results showed that the failed material probably had not undergone proper hardenability heat treatment to produce a hardened surface and a toughened core as the microhardness at the surface and the core were found to be in the range 254-294 HV. In addition, the metallography shows ferrite and pearlite microstructures at both the surface and the core of the failed axle. The SEM analysis of the fractured surface reveals the presence of burnished and crystalline surfaces. This shows that the failed axle does not meet the standard for the axle in terms of chemical, microstructure and hardness properties. The failure of the axle is typical of a fatigue failure.

THE EFFECT OF WELDING METHODS ON THE MECHANICAL AND MICROSTRUCTURE OF HIGH-CARBON STEEL

2025-02-19T11:29:23+08:00

High-carbon steel, with a carbon content of 0.6% to 1.5%, is widely used in critical applications like cutting tools, springs, and high-performance bearings due to its strength, hardness and wear resistance. However, joining high carbon steel is challenging due to its susceptibility to cracking, brittleness, microstructural alteration in the heat affected zone. The impact of welding parameters, particularly current levels, on the mechanical and microstructural properties of high-carbon steel remains underexplored. This research explores the mechanical properties and microstructure of high-carbon steel welded using Shielded Metal Arc Welding (SMAW) and Gas Metal Arc Welding (GMAW) at varying current levels. SMAW was found to produce superior mechanical properties, with SMAW 140A achieving the highest ultimate tensile strength (495 MPa) and elongation (15%). In contrast, GMAW 120A had lower tensile strength (424 MPa) and elongation (10.5%). Higher current levels in GMAW, particularly GMAW 140A, resulted in coarser grain structures and reduced mechanical performance, with a UTS of 317 MPa and elongation of 7.5%. Hardness testing revealed increased hardness in the weld zones of all samples, attributed to the formation of martensite and other hard phases such as pearlite and bainitic ferrite. Microstructural analysis via optical microscopy and SEM showed ferrite, pearlite, martensite, and bainitic ferrite, with SMAW samples displaying a lath martensitic structure and GMAW samples showing bainitic ferrite. These findings suggest that SMAW produces better mechanical properties and microstructural stability, making it more suitable for high-carbon steel applications requiring strength and durability.

OIL SORPTION CAPABILITY OF TREATED HUMAN HAIR SORBENT FOR OIL SEA-WATER CLEANUP

2024-12-23T11:26:43+08:00

This study explored the use of modified human hair as a biosorbent for oil spill clean-up, with a focus on enhancing its oil sorption capacity. Human hair was modified using Sodium Hydroxide (NaOH) and Potassium Hydroxide (KOH) through two methods: hot water treatment at 80°C and mercerization with 5% NaOH and KOH. Structural analysis was conducted, including elemental composition, surface roughness (via Field Emission Scanning Electron Microscopy or FESEM), and hydrophobicity (via wettability tests). The oil sorption capacity was tested using an oil-seawater mixture at different adsorption times (60-100 minutes). Results showed that hair treated with hot water at 100°C achieved the highest oil sorption capacity (2.592 g/g), followed by hair treated with 5% NaOH (2.471 g/g). The optimal adsorption time was found to be 80 minutes, with all samples showing increased oil sorption. The study concluded that hot water treatment significantly improved the surface roughness and hydrophobic properties of the hair, leading to enhanced oil sorption. In comparison, mercerization with NaOH and KOH was less effective in improving the sorption capacity. Raw human hair showed high oil sorption initially, but its effectiveness decreased over extended adsorption times. These findings suggest that modified human hair, especially when treated with hot water, has strong potential for use in oil spill clean-up due to its improved structural and hydrophobic properties.

OPTIMAL CHARACTERISATION OF WELD LINES AND VALVE LOCATIONS IN A THIN-WALLED CYLINDRICAL PRESSURE VESSEL USING FINITE ELEMENT ANALYSIS

2024-12-27T16:30:20+08:00

This paper addresses the critical problem of optimizing weld geometry and valve location in pressure vessel to minimize stress concentration and enhance structural integrity. The study focuses on a thin-walled pressure vessel with a cylindrical body and a spherical head, analysing how different weld and valve configurations impact the stress distribution. The design adheres to the ASME Boiler and Pressure Vessel Code IX, with steel as the base material and EX80XX for the welds. The objectives are to identify the safest weld arrangement and the optimal valve location to reduce structural risks. A combination of theoretical stress analysis and Finite Element Analysis (FEA) was used to evaluate the pressure vessel under a uniform internal pressure of 2 MPa. The study investigated seven valve positions and four weld lines arrangement. Results show that placing the valve at the centre of the spherical head minimizes the stress concentration, while the safest weld configuration is a single weld line at the interface between the cylindrical and the spherical sections. The study further explores the combined effects of multiple valves and weld lines, concluding that placing valves and welds in the cylindrical section increases structural risk compared to the spherical section. This research offers novel insights into the design of pressure vessel, offering optimal weld and valve configurations to enhance safety and performance.

PERFORMANCE ANALYSIS OF HYBRID GLASS AND SISAL FIBRE REINFORCED EPOXY MATRIX COMPOSITE FOR AIRCRAFT STRUCTURES

2024-10-07T12:47:47+08:00

Aerospace industries globally have considered fibre composites as substitutes for structural applications. There is gross challenge to analyse and evaluate the performance of different fibre composites and their manufacturing processes to determine the most effective, efficient and sustainable material for aircraft structures. Therefore, in order to reduce drag in flight, the material for the structure is an important factor to consider in designing aircrafts. In this study, woven E-glass fibre/natural sisal fibre hybrid composite was developed and their mechanical properties, such as flexural strength, tensile strength and impact strength were evaluated. The flexural test results showed that hybrid composite samples (GF30SF5 and GF30SF10), each with an equal amount of glass fibre (30 wt%), exhibited high flexural strength (108.9 MPa and 124.6 MPa) and flexural modulus (2863 MPa and 2667.6 MPa) compared to the SF15 (41.3 MPa and 1771.8 MPa). For the tensile properties, GF30SF5 had the higher tensile strength (118.76 MPa) and Young’s modulus (565.5 MPa) compared to the SF15, while GF30SF10 had the best elongation at break (36%) among the composite samples. As for the impact properties, GF30SF10 had the highest impact energy (11.5 J) and maximum impact strength (0.18 J/mm2) compared to the GF30 and the SF15 samples. Overall, hybridization enhances mechanical properties, with glass fibre showing superior flexural and tensile characteristics. These findings have implications for the development of stronger and more reliable hybrid composites, especially in aircraft structures like wing components. Hybridization is an important replacement for synthetic materials in aerospace application due to their biodegradability, cost-effectiveness and recyclability making them useful in various applications.

2D FLAT PLATE HEAT CONDUCTION WITH CONSTANT THERMAL CONDUCTIVITY: IMPLEMENTING THE ALTERNATING DIRECTION IMPLICIT METHOD

2025-02-27T11:04:54+08:00

The heat equation is widely used in engineering applications to predict temperature distribution in materials subjected to heating or cooling, such as in high-temperature furnaces and pipeline-based heat networks. This study applies the alternating direction implicit (ADI) method to solve a two-dimensional heat conduction problem and evaluates its accuracy through grid convergence and error analysis. Results indicate that finer grid resolutions improve numerical accuracy, with absolute errors decreasing from 15.523 (for a grid size of 110) to 0.493 (for a grid size of 190) at the centre of the plate. Computational efficiency analysis reveals a trade-off, as execution times increase from 0.089907s to 0.432780s for the same grid refinements. These findings confirm the ADI method’s reliability for thermal simulations, offering a balanced approach between precision and computational cost. The study concludes that the ADI method is a robust and efficient tool for modelling heat conduction in engineering applications.

IOT-BASED SMART ENERGY METER MONITORING WITH THEFT CONTROL

2025-03-17T22:05:41+08:00

Electricity theft is an escalating issue, worsened by global warming, which contributes to unbalanced power supply and increased safety concerns. Unauthorized power usage exceeding supply limits often leads to system shutdowns and reduced transmission efficiency. Illegal circuit bypassing has also caused fires, resulting in property damage and threats to public safety. This study presents the design and development of a real-time Internet of Things (IoT)-based smart meter using Arduino technology to monitor energy usage and detect electricity theft. The proposed system involves partial circuit simulation and the development of a full prototype using a direct current (DC) circuit. A Global System for Mobile Communications (GSM) module is integrated to provide remote monitoring and control through Short Message Service (SMS), offering reliable and cost-effective connectivity. When theft is detected, the system triggers a buzzer alarm, displays warnings, and sends power shutdown alerts via GSM. Authorities can then intervene using SMS commands to restore safety. Energy consumption is monitored in real time with updates every 30 seconds. The prototype was tested and successfully validated, showing a maximum error margin of 18% when comparing real and measured power data. The system demonstrated efficient theft detection, real-time monitoring, and remote power control capabilities. This study confirms the feasibility of an Arduino-GSM-based IoT smart meter for real-time electricity monitoring and theft detection. The proposed solution enhances grid safety and efficiency by providing accurate energy tracking, early warning systems, and remote intervention tools.