Research on flexible unloading method for dynamic compaction

During dynamic compaction, frequent heavy load unloading impacts are the main reasons for crane structural damage. To address this problem, a new method to reduce the unloading impact for a crane is discussed. Firstly, through the energy method, an expression for the energy consumption of the unloader that has been ignored before is established and a mathematical model describing the key parameters of the unloader is obtained. Secondly, a force controlled unloader is designed to convert the pulling force control of the wire rope that suspends the heavy hammer into its own hydraulic control. Thirdly, a rigid-flexible coupling model of a crawler crane used for dynamic compaction is built to predict the relationship between the unloading time and the dynamic response. Finally, a new unloader that slowly releases heavy hammer in the air under gravity has been developed and the experimental result proves the feasibility of flexible unloader.