Fatigue Life Estimation of Die-Marked Drill pipes by fuzzy regression method

One of the major problems for the soil project contractors is proper forecasting the Drill pipe fatigue damage Drill pipe fatigue damage occurs under cyclic loading conditions due to, for instance, rotation in a dogleg region [۵]. The present paper used method with linear regressions having independent variables or fuzzy dependent and independent variables to forecast Drill pipe fatigue damage in Iran. The study uses the Least-Squares Linear as an operational criterion. The data required to build the model were collected from observations of ۴۵ places in various projects in Iran. The Mathematica ۶ and Lingo ۸ soft wares were used to make and implement the model. Comparisons of the model's data with those provide by the manufacturers indicates a significant reduction of error on one hand and the ability of the model in accurately estimating the Drill pipe fatigue damage on the other.

Keywords:

Fuzzy linear regression , Fuzzy least-squares Drill pipe , Fatigue