Multi-objective optimization design of a speed reducer gearbox using fuzzylogic Allan C. Magdaong...[et.al].

Thesis (Bachelor of Science in Mechanical Engineering) -- University of Rizal System-Morong.

EXECUTIVE SUMMARY: This research, MULTI-OBJECTIVE OPTIMIZATION DESIGN OF A SPEED REDUCER GEARBOX USING FUZZY LOGIC conducted by mechanical engineering students at University of Rizal System-Morong Campus during the second semester, Academic year 2014-2015 up to first semester, Academic year 2015-2016 was designed due to the current proof of the environmental impact and operational problems of various industrial productions of equipment including gearbox that increased the awareness of the intentional and domestic community with the role of the industry to global climate change and reliability. Since almost all the gearbox carbon footprint and functional problems are attributed to its mechanical elements production including gears and shafts, the researchers explored the possibility of minimizing its carbon dioxide emissions through reducing the weight while uplifting its reliability. To yield the minimum speed reducer gearbox weight and environmental impact while maximizing its reliability, the researchers studied and determined its optimum viable mechanical elements dimensions using grid search algorithm incorporated with fuzzy logic concept. The researchers primarily referred to the study of Chia-Hui Huang mathematical formulation of a speed reducer optimization during the design of a gearbox. Originally, it has single objective problem that minimize its weight while considering the eleven design constraints imposed by the shaft and gear design practices. Based on the simulated results, after design variables satisfied and passed all the constraints it was found that gear face width and module has no significant effect on three objective functions, since its simulated results are constant in the whole simulation. Meanwhile, the remaining design variables including number of teeth, diameter and length of first and second shaft has a direct effect on gearbox weight, reliability and environment impact. On the other hand, the design cost was also analyzed to figure out the economical value of the design. Based from global lambda, the simulated result of overall design cost is 60, 029.0571 in Philippines Peso (Php.) it was revealed that overall cost of the design varies depending upon the simulated results of gear and shaft dimensions including diameter of first and second shaft, gear module and number of teeth. According to the simulated result of 54% Global Lambda (Satisfaction Level) and as compared to Chia-Hui Huang conducted study, speedy reducer gearbox weight, stress and environment impact was successfully decreased a 2.4202% from 23.4482 Kg to 22.8724 kg, 26.1932% from 1104.7677 N/cm2 to 816.8694 N/cm2 and 2.7295% from 1.3336E-02 Person-Year/Gearbox to 1.2972E-02 Person-year/Gearbox, respectively. Therefore, researcher's objectives is satisfied and considered as all true and realistic. Lastly, after consecutive simulation the researchers recommended to use another optimization method and algorithm considering that the increment will be lower than 0.1 or 10% to attain more accurate and reliable results in short length of time. Also include different type of gears and number of stages, other gearbox parts such as bearings, keys and keyways, housing and accessories. However, the researchers suggested to exclude gear face width and module since based on simulated results, the two variables have a constant value.