Frequency Based Substructuring for Structure with Double Bolted Joints: A Case Study

• Published in: International journal of automotive and mechanical engineering Vol. 16; no. 1; pp. 6188 - 6199
• Main Authors: Wan Iskandar Mirza, W. I. I, Abdul Rani, M.N, Yunus, M. A, Ayub, M. A, M. Sani, M. S, Mohd Zin, M.S
• Format: Journal Article
• Language: English
• Published: Kuantan Universiti Malaysia Pahang 01.01.2019
• Subjects: Bolted joints; Degrees of freedom; Engineering; Finite element method; Frequency response functions; Mathematical analysis; Mechanics; Plates (structural members); Steel structures; Substructures; Subsystems
• ISSN: 2229-8649; 2180-1606
• DOI: 10.15282/ijame.16.1.2019.8.0470

Adopting dynamic substructuring schemes is a common practice in the field of structural dynamics, where the dynamic behaviour of a structure is predicted by combining the multiple subsystems that are analysed individually. This paper investigated the dynamic behaviour of a structure with doubled bolted joints using the frequency based substructuring (FBS) method. In the attempt, the substructures were combined with the frequency domain that can be numerically derived or experimentally measured. However, the applicability of this method suffered from several issues where most of them were related to the frequency response function (FRF) of the rotational degree of freedom (DOF) at the subsystem’s interface. In some cases, the system’s interface vibrated in the rotary motion of certain modes, for instance, a car side rear view mirror. Therefore, excluding the rotational FRF during the coupling process could lead to a completely different result. This paper presents the use of the FBS method for a structure with double bolted joints by using the equivalent multipoint constraint (EMPC) method through which rotational DOFs can be completely neglected. The actual tested structure for this study was an assembled structure consisting of two substructures: a simple beam and an irregular plate steel structure. The FRFs of both substructures were derived from using the FRF synthesis from finite element models and combined together via the FBS method. This study reveals that the use of the FBS method with the EMPC method for a structure double bolted joints has led to very promising results.