Implementation of expert system on estimation of fatigue properties from monotonic mechanical properties including hardness

Abstract

This paper describes implementation of the expert system on estimating fatigue properties from simple tensile data or hardness data. The fatigue properties are usually obtained by performing fatigue tests. However, as fatigue test requires time and high cost, many methods have been proposed to estimate the strain-life curves from monotonic mechanical properties including hardness. Though many useful estimation methods have been proposed and they afford every facility, a mechanical designer has some difficulties in making a decision to select the best method among the several methods for the fatigue strength design or assessment under given conditions. And then several researchers including authors evaluated the methods and proposed the best method according to material. In spite of those guidelines, it does not seem to be always easy for ordinary mechanical designer to apply. In this study, an expert system was developed to facilitate it. A commercial expert system shell, Acquire, was used and the user interfaces of the expert system were developed using Visual Basic. The expert system helps mechanical designer to select the best estimation method among methods for estimating fatigue properties from monotonic mechanical properties including hardness, depending on his or her knowledge level of fatigue and has some special functions to describe recommendation and remarks in detail and display the accuracy and predictability of estimation method.