BOLTING: A NEW APPROACH
Summary, December 2013:
The linked paper is a short account of the basic behaviour of common preloaded bolt joints in service, where joint members subject to external loads are clamped by preloaded bolts, and where the latter may be furnished with supplementary bolting members including plain and special washers of any kind and size and bushings that may extend the bolt length even further beyond the combined thickness of the joint members.
The account focuses on tension or tensile joints, also known as joints loaded in tension, under simple conditions where the joint members of a single symmetrical preloaded bolt joint are subject to external loads in the form of pure tension and compression.
In textbooks, these conditions, further simplified by disregarding possible supplementary bolting members, form the basis of the whole understanding of the behaviour of joints, and they are used as the starting point for the description and determination of behaviour in service of the whole range of common preloaded bolt joints.
With this, the account goes beyond the textbooks by extending the conditions dealt with, in connexion with preloaded joints in service, to incorporate possible supplementary bolting members which obviously change the properties and thereby the behaviour of bolt joints.
Based on the account of the fundamental and specific behaviour of common bolt joints, the calculations and illustrations show how it is possible to incorporate supplementary bolting members, and how they change properties and behaviour of bolt joints.
The main conclusion is that it is possible to incorporate supplementary bolting members in a simple consistent way as shown here, and that they may decisively change the behaviour of bolt joints and lead to more efficient use of bolts and thereby to more optimized bolt joints, resulting in greater safety against failure, lower costs, or both.
The following links lead to the newest editions of the paper and its appurtenant spreadsheets.