# Study on Local Vibration Control of the 100 m X-BOW Polar Exploration Cruise Ship
## 1 Introduction  
The 100 m X-BOW polar expedition cruise ship is the first domestic luxury polar expedition cruise ship. This type of ship has the characteristics of diverse equipment, large power, complex hull structure and layout in the engine room, etc. In the design stage, the main frequency of the main excitation force is known, so the main modal frequency of the whole ship and the main excitation frequency can be staggered by optimizing the design of the main hull, so as prevent the whole ship from resonating. However, the hull structure is intricate and complex, the natural frequency of the whole ship can be adjusted through the early optimization design, and it is impossible to make the natural frequency of each local structure avoid the excitation frequency. In the structure of the 100 m X-BOW type polar expedition cruise ship, there are large-area local structures, such as the sun platform, viewing platform, etc., whose main natural frequencies are concentrated in the range of 10 Hz-18 Hz [1], which is easily connected with the propeller and the main engine, causing resonance and affecting passenger comfort, so it is necessary to control local structural vibration. At present, the local vibration of the hull structure is mainly accomplished by optimizing the local structure and changing the structural stiffness to avoid the intrinsic frequency of the main excitation [2; 3; 4; 5], such as modifying the properties of the beam-column section to strengthen the local structural strength, but these methods only can be implemented during the construction stage. When the whole ship enters the commissioning or sea trial stage, it is no longer possible to perform local optimization of the structure. Tuned mass dampers (TMDs) can effectively control structural vibration. [PERSON], [PERSON] [6] installed multiple dynamic vibration absorbers in the body of urban rail vehicles. According to the principle of multiple dynamic vibration absorbers and the characteristics of urban rail vehicles, including multiple dynamic vibration absorbers is established, and a design method of multiple power absorbers applicable to the body of urban rail vehicles is proposed. [PERSON], [PERSON] [7] designed and made a similar test model of the rail box girder structure by taking the railway 32 m simply supported box girder bridge as a prototype. On the basis of verifying the reliability of the test modal, add the additional control of TMDs of the first-order and second-order modal vibration. The vibration response of the measurement point before and after the vibration reduction is obtained by the performance of a single-point vibration excitation test on the test model, and the vibration reduction performance of the TMD on the box girder bridge is analyzed. [PERSON], [PERSON] [8] analyzed the position-related terms in the multiple tuned mass dampers (MTMDs) equation of motion, studied the participation of position in the MTMD vibration reduction control, and proposed an MTMD position optimization method based on the finite element method and the mode shape decomposition method; on this basis, a joint optimization strategy of MTMD parameters and position is formulated. [PERSON], [PERSON] [9] studied the feasibility of the application of a new type of eddy-tuned mass damper (EC-TMD) based on offshore wind torch-type infrastructure from tow aspects of theoretical reasoning and engineering application, aiming at the problem of large vibrations detrimental to the engineering safety of offshore wind power structures under extreme wind load. The results showed that under extreme wind load conditions, EC-TMDs can effectively reduce the vibration displacement amplitude of the tower cylinder top by 21-33%, which indicates that EC-TMD has engineering application value for vibration reduction of offshore wind torch-type infrastructure. [PERSON], [PERSON] [10] used TMD as a vibration control measure to reduce the dynamic response of suspension tunnel tubes under moving loads.