Numerical design and test on an assembled structure of a bolted joint with viscoelastic damping

Abstract

Mechanical assemblies are subjected to many dynamic loads and modifications are often needed to achieve acceptable vibration levels. While modifications on mass and stiffness are well mastered, damping modifications are still considered difficult to design. The paper presents a case study on the design of a bolted connection containing a viscoelastic damping layer. The notion of junction coupling level is introduced to ensure that sufficient energy is present in the joints to allow damping. Static performance is then addressed and it is shown that localization of metallic contact can be used to meet objectives, while allowing the presence of viscoelastic materials. Numerical prediction of damping then illustrates difficulties in optimizing for robustness. Modal test results of three configurations of an assembled structure, inspired by aeronautic fuselages, are then compared to analyze the performance of the design. While validity of the approach is confirmed, the effect of geometric imperfections is shown and stresses the need for robust design.

Dynamic Behaviour Adaptation of Lightweight Structures by Compressible Constrained Layer Damping with Embedded Polymeric Foams and Nonwovens

“…• special sandwich panel cores, for example, in form of truss structures combined with intermediate layers of damping materials [5] or filled with granular materials [6], including cores with voids of optimised geometries [7], • locally acting dampers such as compact acoustic black holes [8,9], structurally integrated resonant metamaterials [10] and joints with viscoelastic damping [11], • active magneto-/electro-or photorheological layers with the damping and stiffness controlled by magnetic, electric field or light, respectively [12][13][14][15][16], • extended concepts of shunted piezoelectric actuator systems [17][18][19][20], • distributed active damping systems that use numerous vibration sensors and actuators attached to complex shaped structures, driven by real-time controllers [21,22].…”

Limitation of estimation method of surface texture parameters by inverse analysis of hammering test data with disturbance

“…One of the simple techniques is the hammering test in which the loosened screw or bolt is detected by the change of the vibration after hammering the target. Similar techniques have been developed, and most of the techniques seem to be based on the comparison with the measurement data and the calculation data of some reference states (Nichols et al, 2006;He and Zhu, 2011;Zhu and He, 2013;Hammami et al, 2016).…”

Impact of nonlinearity on bolt forces in multi-bolted joints: A case of the assembly stage

“…-spring and truss models [21][22][23], -rigid body bolt models composed of a flexible bolt shank and a rigid bolt head [24][25][26][27], -bolt models of the spider type [28,29].…”