Introduction This Item describes methods of analysis of bolted joints in which the bolt is pretensioned and is subject to further tensile load as a consequence of the load passing through the joint. The analysis is designed to allow selection of the bolt pretension such that@ under the application of a known load@ the limiting situations of bolt yielding or joint separation do not occur. In such joints applied loads enter the assembly via the joined members@ usually offset from the bolt@ see@ for example@ Sketch 1.1. The way in which the joined members introduce the load into the joint@ coupled with the stiffnesses and geometry of the components of the joint assembly and its pretension@ governs the distribution of the load among the component parts of the joint. Because of this it is necessary to analyse the load distribution within a joint before its strength or performance can be determined. Some of the stiffnesses involved in such an analysis can only be estimated@ mainly because the associated areas of their influence are imprecise quantities. Accordingly@ analysis should be used to investigate and improve joint design rather than to obtain precise solutions of stresses and deflections within the joint. It should be noted that the entire analysis is carried out in terms of the load on a single bolt but guidance is provided for the case of multi-bolted joints. This section of the Data Item explains the derivation of the analysis used in ESDUpac A8521 and Section 1.14 gives examples of the variation in the pretension required to prevent yield and separation for a typical bolted joint assembly having thin feet. For joints with thick feet the variation of pretension required to prevent separation is shown graphically.
ESDU 85021 B-1995 history
1995ESDU 85021 B-1995 ANALYSIS OF PRETENSIONED BOLTED JOINTS SUBJECT TO TENSILE (SEPARATING) FORCES