Engineering Papers & Publications

During the last two decades, the concept of Fibre Metal Laminates (FMLs) has been evolved to find solution to the requirement of improving mechanical properties and reducing structural weight of elemental components of aircraft structures. In this work FML is prepared using Al 2024 by placing alternately with glass/carbon/aramid Fibres. From experimental results of FML shows greater advantage in mechanical properties then aluminium monolithic layer and this composite fibre laminates individual. The FMLs tested in this work were made of 3 layers of 2024 T3 aluminium alloy 0.28 mm thickness and fibre mats. The 5-3/2 laminates of size 300x300 mm with 3 mm thick were prepared using Vacuum Assisted Resin Transfer Moulding (VARTM) in cold compaction and test specimen were cut by using abrasive water jet machining as per ASTM Standards. The adhesion between fibre and metal layer will play a major role in strength of FML. By keeping this in consideration FMLs were prepared without blow holes and capable of withstanding delamination while preparing specimens through water jet and during various tests employed. The fracture surfaces of destructed specimens are studied with help Scanning Electron Microscope (SEM) image. Similarly, the numerical simulation of all the tests were done using Ansys APDL 10.0 Software. It is observed that aramid FML have substantially stronger in longitudinal directions. Hence, more priority given in this paper to investigate tensile strength and fatigue life of aramid FML.

Boopathy Govindarajan

This study conducted a simulation-based time-domain short-circuits fault evaluation and protection system reliability analysis in 300 MVA substations with 132 kV transmission lines in Asaba (Ibusa/Asaba), Delta State, Nigeria. The analysis focused on two primary parameters: protection system dependability and selectivity, to determine the conditions necessary for ensuring rapid fault clearance and stable substation operation under line-to-ground, double-line, and three-phase faults. Fault currents, voltages, and relay trip signals were generated and analyzed using MATLAB time-domain simulations. Results indicated that system dependability exceeded 97% and security surpassed 95% when total fault-clearing times remained below 120 ms. Relay coordination intervals of 0.2–0.4s, backup misoperation below 3%, and circuit breaker MTBF above 20,000 h ensured selective fault isolation. Extended fault durations beyond 120ms or improperly coordinated relay settings increased the likelihood of misoperation and voltage instability. It was concluded that uninterrupted substation operation depends on integrating time-domain fault evaluation, coordinated relay settings, and reliable breaker performance into protection management protocols. Accordingly, it was recommended that substation operators maintain precise relay coordination, implement continuous time-domain monitoring, and uphold breaker maintenance schedules. These actions will further enhance the protection reliability, reduce fault propagation risks and support safer, more stable operation of the 132 kV transmission network.

FXintegrity Publishing

This study evaluated power system reliability and frequency tolerance requirements for the management of critical-care medical devices at the Niger Delta University Teaching Hospital (NDUTH). The analysis focused on two primary parameters: voltage stability and frequency deviation, to determine the conditions necessary for sustaining Intensive Care Unit (ICU) ventilator uptime and neonatal incubator performance. Voltage and frequency data were collected at regular intervals over a five-month period and analyzed using reliability modeling and MATLAB-simulated multidimensional surface plots. Results indicated that ICU ventilator uptime stabilized at 96.1% when system voltage remained within the 208 and 222V band under controlled load conditions. Neonatal incubator reliability, however, declined sharply when frequency deviation exceeded 0.11Hz, activating maintenance thresholds. Extended voltage dips below 185V and frequency excursions above 0.12Hz were associated with increased likelihood of device failure and elevated corrective maintenance demand. The findings underscored that uninterrupted operation of critical-care devices depends on integrating voltage and frequency reliability metrics into equipment management protocols as conclusion. Accordingly, it was recommended that NDUTH management implement continuous power-quality monitoring, enforce maintenance protocols guided by operational thresholds, and strengthen redundancy measures. These actions will enhance device reliability, reduce service interruptions and support safer, more consistent delivery of critical care in the hospital setting

FXintegrity Publishing