Analysis of the Tightening Process of Bolted Joint With a Tensioner Using Spring Elements

Abstract

Hydraulic bolt tensioners are frequently used to tighten critical structural members with accurately controlled clamping force. The ratio of desired clamping force to initial tension is the most important factor to be predicted in advance for given joint configurations, which is termed “effective tensile coefficient” here. In this paper, an elementary and extensive approach to estimate the coefficient is proposed using spring elements, and a simple and practical equation is presented to evaluate the magnitude of “effective tensile coefficient” in terms of five spring rates of each part consisting of the joint. The relationship between “effective tensile coefficient” and grip length is investigated, including the influences of Young’s modulus of fastened plate. The validity of the elementary method proposed here is ascertained by comparing the results to those by experiment and FEM.