Journal of Engineering & Technological Advances

REVIEW OF STRUCTURE AND APPLICATION IN THREE-AXIS CNC MACHINING: ERRORS, TOOL PATH STRATEGIES, AND EFFICIENCY IMPROVEMENTS

2024-06-24T11:51:09+08:00

The increasing demands for rapid production have significantly boosted the use of CNC systems in industries. Over the past decade, efforts have concentrated on improving the time efficiency and accuracy of CNC machines. This paper reviews research on CNC machine structures, highlighting common errors such as geometric inaccuracies. It examines advanced tool path generation strategies, including traditional methods and next-generation algorithms like genetic algorithms and the simplex search method. The review assesses these strategies' impacts on machining efficiency and accuracy, comparing current and historical approaches. The objective is to present a comprehensive overview of advancements in CNC machining, contributing to the development of more efficient, precise, and reliable manufacturing technologies.

BIOMECHANICAL RESPONSE COMPARISON OF NIGERIAN CHILD ANTHROPOMETRIC TEST DEVICE (ATD) AND HYBRID III DUMMY

2024-02-08T13:47:19+08:00

Anthropometric Test Devices (ATD) or crash dummies are used to simulate the response of human beings in crash tests of vehicles. There is concern about the difference in anthropometry of people from various locations of the world and current crash test dummies used in safety certification of vehicles. Three-year-old (3YO) Hybrid III dummy may not represent Nigeria children because they were produced using United States child anthropometry. The aim of this work is to investigate how the size of 3YO Nigeria child dummy affects crash injury outcomes in Finite Element (FE) crash analysis. FE dummy model that is scaled to Nigeria child anthropometry was used to simulate a sled test and the injury parameters such as head accelerations, chest acceleration and resultant upper neck moment and force were evaluated and compared with experimental results of with the view to ascertain how good can represent Nigerian child in crash test. The results show that is different from in head acceleration and chest acceleration by 29% and 6% respectively. Nigerian child resultant upper neck moment and force were 10% and 23% respectively lower than . Difference in the injury outcomes means that model cannot represent three-year-old Nigerian child in certification. Hence crash dummy of Nigerian child anthropometry is necessary in certifying vehicle safety performance for cars used in Nigeria.

ASSESSING THE RAPID DRAWDOWN RISKS ON SLOPE STABILITY

2024-06-12T14:21:58+08:00

This study investigates the slope failure that occurred at a 152.18-acre residential development in Kulim. The unreinforced slope was reported to be deemed stable before its failure in the mid-April 2023. Continuous pumping activity for nearby basement construction had been underway for several weeks prior to the failure. To confirm the causality of drawdown effect, the groundwater level was monitored using two piezometer standpipes. The fieldwork investigation confirmed a significant difference in groundwater levels caused by the dewatering activities. By developing a numerical model using Slope/W software, slope stability analysis was performed to assess the slope performance before and after the failure, analysing the impact of dewatering. The findings revealed a significant reduction in the factor of safety (FOS) from 1.348 to 1.080, not adhering to the Jabatan Kerja Raya (JKR)’s slope specifications of a minimum FOS of 1.3 for unreinforced soil. The findings also confirmed the detrimental effect of rapid drawdown on the strength of the slope. To mitigate the slope failure, gabion walls were proposed as cost-effective alternatives. This remedial measure increased the FOS to 1.612, meeting JKR specifications of a minimum FOS of 1.5 for reinforced soil. The findings highlight the importance of educating on groundwater management to enhance safety and mitigate similar risks in future projects.