Experimental Studies of an Asymmetric Multi-Bolted Connection under Monotonic Loads.

Rafał Grzejda,Arkadiusz Parus,Konrad Kwiatkowski

doi:10.3390/ma14092353

Abstract

This article describes the experimental studies of a preloaded asymmetric multi-bolted connection in the exploitation state. The construction of two stands were introduced: for bolt calibration and for evaluating the bolt forces in a multi-bolted connection. The bolts were tightened in a specific optimal sequence, in three passes, monitoring the force values in the bolts using a calibrated strain gauge measuring system. The studies were conducted for the selected multi-bolted connection on an Instron 8850 testing machine. The measurement data were saved in MATLAB R2018b Simulink. The measurement results were analysed statistically and are presented via charts showing the distributions of the normalised values of the bolt forces as a function of the linearly increasing and decreasing exploitation loads. We show that the forces in individual bolts, after unloading the multi-bolted connection, change in relation to the initial values of their preload.

Highlights

Multi-bolted connections are one of the most commonly used nodes in engineering structures
The results of experimental tests of the tightening process of the selected asymmetric multibolted connection were described in a previous study [6]
The Z1 index enables a relative evaluation of the changes in bolt forces during loading of the multi-bolted connection;

Summary

Introduction

Multi-bolted connections are one of the most commonly used nodes in engineering structures. Hoang et al [17] experimentally tested bolted flange connections in pipe structures subjected to various types of loads. The conducted review shows that, currently, the most frequently analysed are typical multi-bolted connections occurring in engineering structures such as: flange connections, lap connections, connections in truss nodes, or beam-to-column connections. As mentioned above, these are most often symmetrical systems. We studied a multi-bolted connection using geometric and load asymmetry This gives the tests a sense of universality and makes the tests innovative compared with those described in the literature.

Bolted Connection and Bolt Calibration

Conclusions