Modeling of the behaviors of cranes under seismic effect and active control of vibrations

Importance of earthquake damages on Crane structures is understood at the beginning of 2000s. One of the main reasons of this late perception is the usage of heavy capacity cranes is not so prevalent. But on recent years mass production and consumer behaviors entailed the usage of huge ships, bigger harbors, therefore heavy capacity cranes are needed and constructed widely. Another reason is that there is no such experince to see the effect of earthquakes on crane structures. But on 1995 the destructive effect of Kobe earthquake on crane structures is showed the importance of the subject. On this earthquake, crane structures are damaged easily, therefore earthquake resistant crane structures are needed. After the date of Kobe earthquake, improving the seismic performance of crane structures are studied both in academia and industry. The problem could be defined as ?the problem of minimizing the earthquake caused structural vibrations on cranes.? One of the recommended solutions to the problem is active control of vibrations on crane structures.The main purpose of this Phd thesis to develop a multi degree of freedom mathematical model to fulfill the dynamic behavior of crane structures under seismic loading, and to reduce vibrations using active control technique. For active vibration control, an actuator saturated control algorithm is developed. In this context, the thesis, the developed mathematical model, presented as a solution to the problem of reducing the structural vibration caused by the earthquake (active vibration control) and the designed control algorithm (actuator saturated mixed H2/H ? controller) contributes to the literature in many areas.These objectives are in line with the thesis, consists of two main parts. The first main section, revealing the dynamic behavior of cranes subjected to earthquake, multi-degree of freedom mathematical model is a mathematical model was developed and the accuracy 1/20 scale model of the crane on the shaking table has been confirmed through experiments using real seismic datas. Investigation earthquake effects on cranes, observing dynamic effects, taking appropriate constructive precautions and with active-passive control procedures it will be able to ensure stabilities by developed mathematical model.In the second main part, active vibration control has been suggested as a solution for reducing structural vibrations that are based on earthquake. For this purpose, the control algorithm has been designed. Recently, studies that suggest active control application for isolating of vibrations that are based on earthquakes have accelerated. Reducing structural vibrations that are based on earthquake subject is a new and open for improvement. By this way, for increasing seismic performance of cranes, a new method is suggested.Recently, in parallel with improvements in solution of durable control techniques, in many engineering problems H2 and H ? control structures have been preferred mostly. Active vibration control application is one of the most important one of these problems. The most important reason, in order to prevent the exposure of the system disturbance inputs from disturbant outputs, the idea of making the minimum norm of an infinite matrix, the resulting transfer functions H ? control structure be known in advance such as earthquakes, adverse entries in the severity and characteristics of structural systems under the influence of a control algorithm is well suited for. However, the H ? control design relates to the field of more frequency. A closed-loop system can not guarantee a good transient response. The transient responses of control are more successful than the H2. Therefore, the Phd thesis, in order to achieve the desired frequency and transient responses, H2 and H ? control structures, linear matrix inequalities (LMI?s), obtained in accordance with the hybrid approach, H2/H ? control structure is used. However, the active structural control seismic loads a major problem because of incidental situation, the force necessary control is needed, the actuators used in these capacities. "Actuator saturation problem? referred to as this closed-loop performance of the system and may lead to serious deterioration, however, may cause instability. Overcome this problem and the proposed method to be applied in practice, designed a mixed H2/H ? control were included in architecture in the form of actuator saturation constraints DME event. In this way, providing optimum performance, depending on the actuator saturation limit for back-feed actuators can be applied in practice fulfilled mixed H2/H ? control algorithm is obtained.In conclusion, the effectiveness of the proposed control algorithm, and the active control system subjected to earthquake simulation studies where a crane is shown time and frequency responses. The results of simulation studies using actual earthquake records, the proposed control algorithm, which guarantees the stability of the system and the Cranes actuator saturation constraints arising from the earthquake shows that it has significant potential to reduce structural vibration.