Laminated composite structures have been increasingly used in engineering structures due to the beneficial properties such as light weight, high stiffness-to-weight ratio, high strength-to-weight ratio and design flexibility. Understanding the vibration behaviour of composite structures is of vital importance to achieve optimal structural design with excellent dynamic performance in terms of low vibration and noise level. However, because of the complexity in modelling and simulation, the vibration energy flow behaviour of laminated composite structure remains largely unexplored and needs detailed investigations. The vibration power flow analysis (PFA) approach is a widely accepted technique to characterize the dynamic behaviour of complex structures. It has been extensively used for vibration analysis of metallic structures, but not of composite materials. This thesis aims to develop effective vibration power flow analysis methods for laminated composite structures to reveal its dynamic behaviour and vibration energy transmission characteristics.
PFA based on analytical and numerical finite element methods is carried out to determine the vibration energy input, dissipation, and transmission of composite structures subjected to external excitation force. Both constant stiffness laminated composite (CSLC) plates with straight fibres and variable stiffness laminated composite (VSLC) plates with curvilinear fibres are considered. It is shown that the fibre orientations and stacking sequences have significant effects on the power flow characteristics and dominant vibration transmission paths. For the coupled system such as plates attached with passive devices and coupled L-shaped composite plates, a substructure approach based on analytical and numerical methods is employed to obtain steady-state dynamic response and vibration power flow variables. It is demonstrated that novel inerter-based suppression devices can be attached to the composite plate to modify its vibration transmission and suppress vibration level according to specific design requirements. The fibre orientations of the single or coupled composite plates can be tailored for desirable energy transmission paths.
The work described in this thesis reveals that structural design and optimization of composite structures with enhanced vibration suppression performance can be achieved based on vibration energy flow and transmission behaviour. These findings provide new insights for the enhanced dynamic designs of laminated composite plates by tailoring fibre orientations and the suppression of their vibration using inerter-based passive devices. This thesis yields an improved understanding of power flow behaviour of composite structures.
|Date of Award
|11 Jul 2021
- Univerisity of Nottingham
|Jian Yang (Supervisor) & Chris Rudd (Supervisor)
- power flow analysis
- laminated composite structures