A Modal Analysis of Giant Shipbuilding Tower Crane

Old giant cranes in corrosive environment are in serious hidden danger of structural instability and failure, the modal analysis is an important part of dynamics analysis in the Crane Safety Evaluation to guarantee the safety of cranes. A Modal Analysis of a 28-year old 100t giant shipbuilding tower crane was done using ANSYS. Comparing with the vibration frequencies and modal shapes, Modal analysis shows that the Natural Frequency of the crane reduces from 1.0024Hz to 1.0003Hz, beside all the Modal vibration frequencies (first 10 Order) of the crane are lower than the designed value, means the strength of the tower crane has decreased; the Modal Vibration Frequencies (first 10 Order) of the tower crane are between 1 Hz and 2 Hz. The Mmodal analysis provided theoretical basis for safe use, design and transformation of this crane.