Papers by Author: Ishaya Musa Dagwa

Abstract: Beam-like members such as shafts, levers, frame components, beam structures, etc. are regularly designed and constructed in the field of mechanical and civil engineering. It is pertinent to know the structural integrity of the design before construction or fabrication. Beam deflection and stress calculations can be cumbersome and results from commercial simulation packages are not devoid of truncation and/or round-off errors because they are based on numerical schemes. To reduce or eliminate these issues, a computational tool, CABDA, has been designed and developed on matlab. The algorithm is based on analytic equations of beam deflection and bending stress theories; a design flow chart and graphic user interface were done to implement the algorithm. Experiments and simulations have been carried out for steel and brass rectangular beams which were compared with results obtained from CABDA for the same beam model. Average deflection errors recorded for steel beam are-0.4 and-0.015; for brass beam are-0.69 and-0.1 for experiment and simulation respectively. Average bending stress error recorded is-0.19 for simulation. It is observable that simulation results compare closely but CABDA gives exact results and therefore is very appropriate for simple beam problems.

Abstract: Calibration curves of a multi-component dynamometer is of essence in machining operations in a lathe machine as they serve to provide values of force and stress components for cutting tool development and optimization. In this study, finite element analysis has been used to obtain the deflection and stress response of a two component cutting tool lathe dynamometer, for turning operation, when the cutting tool is subjected to cutting and thrust forces from 98.1N to 686.7N (10 to 70kg-wts), at intervals of 98.1N(10kg-wt). By obtaining the governing equation, modeling the dynamometer assembly, defining boundary conditions, generating the assembly mesh, and simulating in Inventor Professional; horizontal and vertical components of deflection by the dynamometer were read off for three different loading scenarios. For these three loading scenarios, calibration plots by experiment compared with plots obtained from simulation by finite element analysis gave accuracies of 79%, 95%, 84% and 36%, 57%, 63% for vertical and horizontal deflections respectively. Also, plots of horizontal and vertical components of Von Mises stress against applied forces were obtained.

Abstract: In Recent Times, Environmental Concerns Arising from Pollution, Global Warming and Waste Management Have Led to the Generation of Interest in the Use of Environmentally Friendly Materials, Especially, Biological Materials such as Natural Fibres and Particulates in Composite Materials Manufacture. in this Work, Natural Fillers (Afara-Mahogany Particulates of 150µm) and Fibre (Caesar Weed Fibre of 5mm Length) Were Mixed with Epoxy Resin at the Various Fibre/filler Weight Percentages as Follows: 2%, 4%, 6%, 8% and 10% with Random Fibre Orientations. some Physical and Mechanical Properties of the Composite Were Determined Using Standard Procedures. Ninety (90) Wt% of Epoxy Resin Mixed with 10 Wt% for each of the Following: Caeser Weed Fibre, Afara and Mahogany, Improved the Tensile Modulus by 2652.6%, 321.37%, and 129.73% and the Impact Strength by 162.7%, 133.9% and 15.25%, Respectively. Also, Composites Density Reduced by 26.26%, 3.03%, and 3.03%, and its Hardness too Reduced by 5.41%, 1.35%, and 4.05%, Respectively. Meanwhile, the Water Absorption Were 4.9%, 2.79%, and 4.12% for 10wt% of Caeser Weed Fibre, Afara and Mahogany, Respectively and 90wt% Epoxy Resin. Therefore, Caeser Weed Fibre Had the Greatest Positive Effect on the Tensile Strength, Impact Energy Absorbed and Density. however, Afara-Epoxy Composite Had the Least Water Absorption and Higher Shore Hardness Value than Mahogany-Epoxy and Caeser Weed Fibre-Epoxy Composites.

Abstract: This paper focuses on the design of a sub-press mould mounted on a 100-Tonne hydraulic press during compression moulding of composite materials manufacturing process. The sub-press consisting of platens, punch and mould, and guide columns were designed using Microsoft Visual Basic software to minimize time wastages in trail-and-error procedures and mould modifications resulting after the mould is manufactured. Graphical representations of variables which were used in the design such as: platen thickness, guide pin dimensions, clamping force, heat supply, heat losses, and heating element were obtained. The program developed was tested on a solved example in a standard textbook and the result obtained compared well with the result in the book.

Abstract: In this study, an attempt has been made to optimize cutting parameters (cutting speed, depth of cut, and feed rate) in conventional turning operations. A Taguchi orthogonal array (L933) was used in surface roughness optimization of a solid round bar of mild steel material. The experimental runs were randomized; two skilled machinists were involved in the turning operation using the same machining parameters. ANOVA analysis was performed to identify the percentage contribution of the factors affecting surface roughness during machining. The optimal cutting combination was determined by using the signal-to-noise ratio and the following results were obtained; speed (level 2) = 55.m/min, depth of cut (level 3) = 0.08mm, and feed rate (levels 3) = at 0.08mm/rev. A prediction of surface roughness was carried out using the optimal setting followed by a confirmatory test on the lathe. The result shows that the confirmatory runs compared favourably (96.44%) with the predicted surface roughness.