Modal Properties of Bolted Housing depending on the Methodology of a Solution of Bolted Joints

Abstract

This paper presents the research of modal characteristics of the bolted housing. The aim of the research was to find out the impact of the methodology of the solution of bolted joints on modal characteristics of the bolted housing of the gearbox unit. Results of research can be applied to bolted housings of any machineries. An impact of bolted joints and their modal properties was also the subject of research. The first three analyses focused on an application of various approximations of bolted joints. The analysis of their substitution by a simplified 3D geometry was solved. The second analysis focused on an application of Beam elements and the third one focused on substitution by bonded contact types. The fourth analysis regarded housing as one body without bolted joints. The impact on modal properties of pre-stress load in joints was researched. The housing was also loaded by the torque moment of an electric motor by means of bearing reactions and also the weight of the motor and brakes mounted to the housing. The article also deals with the efficiency of individual methods regarding the calculation time.

Stiffness as a criterion of dynamic load carrying capacity of tension-loaded bolted joints

“…The most common separable connections in machine systems are bolted joints [1][2][3]. Designing bolted joints is a responsible engineering activity because the connection points are often the most dangerous places, where fractures or loss of hermeticity occur most often, due to insufficient strength or stiffness [4,5]. The experience of applying bolted joints shows that the joint stiffness is in most cases less than the stiffness of the individual parts that are joined, so this should be taken into account when designing and calculating bolted joints.…”