Double Butt, Bolted Connections-Influence of Prestressing

Abstract

This chapter presents a project to develop a 3D computational finite element method model of double butt prestressed bolted connections taking into account the effects of bolts, initial gaps, friction, and prestressing force. This model may be used especially for investigation of the connections deformability, also after first slip not taken into account in the method of structures analysis used in the everyday engineering practice. There are some design parameters that are considered: initial yield stress, hardening modulus, friction coefficient, and prestressing force magnitude. To deal with these effects, a finite element model is created. The computational model is developed in the framework of ABAQUS general-purpose program. The connection is discretized with about 7500 3D-isoparametric brick elements. All parts of the connection are separated. Initial gaps are assumed among all of the elastic bodies and later, during the loading process, non-elastic bodies, and the contact surfaces are established. The proposed model is verified by experiments. The 20 specimens that are the connections in technical scale are investigated. Comprising the results obtained theoretically, as well as in experiment, shows that the 20 specimens differ insignificantly; it means that the proposed model can take advantage in workout of simplified models used in everyday engineering practice.