Shear Load Transfer and Relaxation in Bolted Joints with Fractured Surfaces [article]

Peter Lyszczan, Dietmar Göhlich, Technische Universität Berlin, Technische Universität Berlin
2012
Shortly after the introduction of the fracture splitting as a standard process of con-rod production a number of engine failures occurred due to the self loosening of con-rod bolts. While the fracture splitting process was aim of intensive research and optimization, the mechanical behavior of a joint with fractured surfaces was not. The research described in this document focuses on the determination of two mechanical properties that are crucial for the design of a bolted joint with fractured
more » ... nt with fractured surfaces: shear load transfer and relaxation. This was accomplished by experimental investigations using a special kind of specimen that was created based on fracture splitted con-rods. The most important parameters for the tests were surface topology, temperature as well as embedded particles (for relaxation) and preload (for shear load transfer). It turned out that relaxation in bolted joints with fractured surfaces is not significantly different from relaxation in bolted joints with plain surfaces. The amount of transferrable shear load is between 0.8 and 1.9 times the amount of installed preload and is showing a non-linear behavior. A mechanical model was successfully set up to describe all distinctive features of a joint with fractured surfaces. With these results bolted joints with fractured surfaces can be designed easier and much more safely
doi:10.14279/depositonce-3131 fatcat:7pvygskqqnaudpkhvxhcyy4pqq