Optimisation and Reliability for Geometrical Tolerance Value against Positional Characteristic in Rotational Shaft System

Abstract

In the process of manufacture and installation, geometrical dimensions and tolerances (GD&T) should be taken into consideration to improve reliability and reduce the adverse impact on critical parts of the rotating system. GD&T must be considered by manufacturers and assembly worker. This paper presents an analysis of geometrical tolerance (GT) values in rotational shaft using the genetic algorithm (GA) method. GA optimization uses a geometric mathematical model. Mathematical models were developed using the offset and algebraic methods to calculate the ideal geometric features that best fit a set of positioning points based on the standard equations criteria. The calculation using the Matlab software application will use the optimal GA parameter. There is a combination of four genetic parameters associated with size population, crossover, mutation and stop state will develop algorithm performance which will produce optimum GT value. The geometric tolerance value for the position characteristic was analyzed to determine and predict the probability and reliability shaft in rotational system. Comparative values of each GT value are compared to find out the reliability values obtained can be used and verify the GT value requirements require mathematical representation. Tolerance analysis at the design stage to evaluate and predict quality by considering the probability of failure rates. The Actual value of the radius must be small from the allowable radius (Ract <Rallow) to cope with the high failure rate throughout the operating period. Due to dynamic nature of the shaft round and the possibility of a variable size of shafts, the GT value should be analyzed to ensure that the value obtained is correct and can be optimum solution to this problem. The GT value to be considered is at the center of the shaft involved which will affect the relevant components. Impact of GT value on the destruction of system critical component such as bearings, gear and couplers as benchmark for review for the optimization of shaft geometric tolerances in rotating machines to overcome the problem and improve concentricity shaft. The contribution of this study is to examine the effect of shaft size and the value of geometric tolerance on system reliability. Estimating and predicting levels of reliability more accurately improves system life, knows the system's impact accurately, knows the security level of a rotating system and also knows the quality of the mechanism at the design level.