Stability and Serviceability of Controlled Structures
September 17, 2018 — September 21, 2018
- Sara Casciati (University of Catania, Italy)
- Marian Wiercigroch (University of Aberdeen, UK)
The aim of this course is to discuss fundamental and practical concepts for assessing the stability and the serviceability of controlled engineering structures.
Pioneering works in applying control strategies to large-scale complex structures such as buildings and bridges have been mainly motivated by the protection of the built environment from earthquakes. Therefore, the uncontrolled structural systems are likely to have either approached or already entered the inelastic limit state. Recent advances in new material technologies enable to design highly flexible large-scale structures for which the limit states of stability and serviceability become of critical importance. It would be desirable that control solutions are developed in the design stage of these structures. Alternatively, retrofitting measures to introduce affordable control strategies together with their maintenance planning are typically required.
Structural stability is, in all cases, a key criterion in the design and service of most systems and structures where safety is paramount. Hence, there is a need to carefully assess the effects of the control devices on the global structural behaviour with respect to the stability limit state.
Vibration mitigation is often implemented to meet the serviceability requirement. Different solutions ranging from active to passive and semi-active control strategies are available but their feasibility and maintenance may be prohibitive. For these reasons, there is a need to preliminarily estimate their effects by investigating the serviceability of the controlled structures. In these studies, the testing of real-world large-scale structures is essential to support the validity of the approach.
The course will be structured into two series of three modules. Each module will consist of six one-hour lectures. The specific contents of the modules are summarized as follows. In the first module, a two-sided damping constraint control strategy for a quasi-zero-stiffness isolators is shown to improve the system stability. The second module is dedicated to the stability of passively controlled structures using either nonlinear energy sinks or piezoelectric devices. In the third module, thin plates and shells made of either piezoelectric materials or dielectric elastomers are embodied into smart structures as eigenstrain actuators to control stress and structural stability. In the fourth module, the serviceability assessment of controlled footbridges is discussed. The fifth module is dedicated to the recently developed control strategies for improving the vibration performance of floor structures. In the sixth module, the emerging trends in the vibration control of both onshore and offshore wind turbines are presented.
The course is addressed to doctoral students and postdocs in the fields of Civil and Mechanical Engineering, as well as Mechatronics, scientists, industrial researchers, and practicing engineers interested in the research areas of linear and nonlinear dynamics, stability and control.