Nümerik ve deneysel yöntemlerle karmaşık paneller üzerinde aktif titreşim kontrolü uygulaması: Araç seviyesinde gösterimi

In recent years, customer requirements for comfortable and quieter vehicles have inspired the automotive manufacturers to introduce new technologies to improve the noise, vibration and harshness (NVH) characteristic for new models. Moreover, the automotive manufacturers need to stay within the weight limits to be competitive in the market while achieving required NVH performance. As an alternative to conventional passive treatments such as mass-damper mechanisms, damping layers and heavy acoustic packages, low weight piezoelectric patches can be easily integrated to vehicle panels to reduce vibrations due to external disturbances actively Active vibration control (AVC) implementations in the literature are mostly focused on simple geometries with properly defined boundary conditions. However, in real life applications, the structures are much more complex than simple plate and beams. Furthermore, the boundary conditions are not usually well-defined. In this thesis, an active vibration control methodology is developed which incorporates numerical and experimental studies in a structured framework to reduce undesired vibrations of complex systems. In this thesis, first, the developed methodology is demonstrated on a representative vehicle model in the laboratory environment considering the complex shape, boundary conditions and geometric constraints. Optimum location for the sensor/actuator pair is determined numerically by using a validated finite element model (FEM) of the complex structure. Once the optimum location is determined, the controller parameters (e.g. damping and gain) are varied based on Design of Experiments (DOE) technique to search for the optimum parameter configuration in the design space. All the DOE configurations are performed experimentally to include the hardware and controller limitations in the analysis. Response Surface Methodology (RSM) technique is utilized for identifying the relationship between the design parameters and the controller performance. The vibration suppression performance is evaluated based on two control metrics, the amplitude reduction at the targeted frequency and broadband energy reduction. Single and multi-objective optimization case studies are performed using the above metrics. Finally, the same approach is extended to a real vehicle with hardware modifications due to power constraints in the operating condition. It was observed that the developed active vibration methodology can be applied effectively to complex systems to reduce the undesired vibrations. Moreover, the methods presented in this thesis can be implemented to other areas such as aerospace and marine applications.