On the Natural Frequency of the Derrick Post

Abstract

In treatment of the natural frequency of the derrick post, we can calculate the frequency assuming the post as a continuous beam. In general the natural frequency of the derrick post is thereby calculated from the following equation, [numerical formula] in which λ_1 is influenced by many factors such as shearing force, rotary inertia, variation of cross section, accessory weight, with or without truss on the top of derrick post and condition of supporting points etc. We acquired λ_1 curve after the theoretical and experimental investigations for these factors. Then in the stage of initial design, we can design the derrick post which is free from the trouble of vibration.