Methodologies in On-line Life Assessment of Hot Section Components Under Varying Operating Conditions (GTF Approaches Versus RSM Approach)

The most complex material selection procedures and expensive fabrication methods are for components which are exposed to dynamic loads at elevated temperatures. Since in real industrial condition such critical components are subject to varying operating conditions assumption of a constant operating profile in residual life assessment will lead to inaccurate and uneconomical results. Various methods and techniques in on-line remaining life assessment of hot section components such as Green‟s Transfer Function technique (GTF), GTF technique along with a data base, Component Mode Synthesis (CMS) together with GTF technique, and Response Surface Method (RSM) have been reviewed in this article. Examples of real industrial applications for each of the methodologies are presented and their advantages and disadvantages are discussed. GTF is best applicable to linear systems but for nonlinear cases results in considerable errors. Modified approaches of GTF require either on-line or off-line considerable computational efforts. RSM approach is applicable to both linear and nonlinear cases and requires no on-line FE calculations

Keywords:

Hot section , on-line residual life assessment , GTF , CMS , RSM , Varying operating conditions