Manoj Chouksey

Experimental study of loosening behavior of plain shank bolted joint under dynamic loading

Purpose – Bolted joints are commonly used to connect structural members. These joints can be disassembled whenever required. Various types of washers are used between nut and the connected member to keep the joints tight. However, these joints often become loose over time under dynamic loading conditions. The purpose of this paper is to know the reasons of loosening of bolted joints and to identify the main parameters that contribute to the bolt loosening, and to verify them with previous work. Design/methodology/approach – This work studies loosening of bolted joint in a test rig under varying tightening torque as well as for various types of washers used as the number of load cycles increases. Four trial runs are taken for each case considered and the average results are found out to minimize possible sources of errors. For the purpose, a specifically made test rig is used which is capable of applying harmonic load on the bolted joint by the lever action. Findings – The study compares the loosening of b...

Dynamic analysis of multi-mesh geared rotor system using modal analysis

Multi-mesh geared systems are common in many applications including rotorcraft and automotive transmissions. Coupling mechanism occurred due to gear meshing often influences dynamic characteristics of geared rotor system. This paper primarily studies the dynamic behavior of the multi-mesh rigid geared systems supported on roller bearing to include effect of gear mesh coupling in multi-mesh transmissions. This formulation combines constant mesh stiffness value in a multi-body dynamics model. Modal analysis technique is used to determine dynamic characteristics like natural frequency and forced harmonic responses of the system. The resulting modal solutions obtained for geared system are compared to study the effect of change in bearing compliance on system dynamics.

Multi Speed Model Updating of Rotor Systems

Accurate Finite Element (FE) models of rotor systems are required for predicting its dynamic behavior, in dynamic design and fault identification purposes. In inverse eigen-sensitivity method of finite element model updating, the limited number of measured eigenvalues available at any spin speed restricts the maximum number of parameters that can be updated. This paper proposes a multi speed model updating method based on inverse eigenvalue sensitivities to update parameters of a rotor system. The method uses eigenvalues obtained at more than one spin speed to update the model. Such an approach allows not only to update more number of parameters but also helps in obtaining a more consistent estimate of updating parameters.