Optimization of weld quality properties using Analytical Hierarchy Process (AHP)

Abstract

The premature failure of structural materials is a ubiquitous engineering problem and a huge source of concern cutting across all strata of engineering. Thorough investigations along with root cause analysis involving physical inspection, and considering all other variables;it has been observedand proven that these failures originate at welded joints. Research shows that metal structures at their welded joints do not have the same strength characteristics as the parent material. One of the proven ways of enhancing the strength of a structural material at welded joints is to systematically select a process that optimizes each parameter combination aimed at ensuring that at all times, all factors are thoroughly considered and a well thought out plan is brought to bear to ensure that each joint attains the strength and reliability standard of the parent metal. Over the years the desired process parameters of welded joints have been gleamed out by applying various multi criteria optimization tools and statistical models in an attempt to broaden the scope, and increase the options open to researchers and developers in arriving at optimum process parameters to meet specific needs.In this study the Analytical Hierarchy Process (AHP) was utilized to systematically select the process parameters and the corresponding weld properties. From applying the AHP, weldment 7, was selected to possess the optimum process parameters and weld properties. These weld properties conform to the standards used for categorizing the weld property which falls within the quality criteria determined by other researchers. In this study, the AHP has been successfully used to optimize the weld properties of a low carbon steel material welded using the Tungsten Inert gas welding process. A step by step method was utilized.However there is a caveat. The consistency ratio of the AHP was determined to be 67% which is above the 10% needed to make the inconsistency acceptable. This indicates that the comparison survey map should be revised and further studies required to more effectively adapt the AHP process which the author believes has real potential.