Abstract:
Every structure tends to vibrate at particular frequencies, called resonant or natural frequencies. Each natural frequency is associated with a certain shape, called mode shape that the model tends to assume when vibrating at that frequency. When a structure is excited by a dynamic load with a frequency coinciding with one of its natural frequencies, the structure experiences stresses and large displacements.
In this research effective mass participation factor criterion is used to solve the vibration problem in the ship mast. The effective mass participation factor provides a measure of the energy contained within each resonant mode. Vibration problem originates when one of the antenna at top of mast is replaced by a new antenna with greater mass at same location. The overall mast structure starts vibrating because of the resonance of natural frequencies of the mast structure with natural frequencies of rotary equipments. It causes interruption in sensitivity of equipments installed on the mast structure. Instead of fabricating the new mast structure, some alteration has been carried out on the basis of results obtained from modal analysis. Modal analysis is used to obtain natural frequencies and mode shapes of the structure. Mass Participation of resonant modes is further refined by using bureau VERITAS and Military standards.
