Research On Dynamic Characteristics Of Grab Dredger Operation

Grab dredger is a kind of important dredging equipment, widely used in the construction and maintenance of ports and waterways, as well as national defense construction, irrigation and water conservancy projects. With the continuous growth of dredging market scale, the demand for grab dredger is also growing, but at present many technical problems still exist in the parts of independent design and manufacture of grab dredgers, especially reference lacking on the issues of grab dredger's load calculation in the operation process. In most cases, accuracy and rationality cannot be ensured by calculations based on empirical formulas.Operating state of the grab dredger changes frequently. Because of inertia force and impact effect, a dynamic load engenders which is of great significance to the design, calculation and safe operation. Due to working conditions in water and difference from land lifting equipment, the influence of water force is considered. For lack of researches on dynamic characteristics in grab dredger's operating process, this paper takes 18m3 grab dredger as the research object to research on the dynamic characteristics. The specific content is listed as follows:(1) Summarize the basic theory of dynamics calculation in mechanical system and fluid mechanics simulation, and pave the way for the smooth completion of the simulation calculation.(2) According to the characteristics of a grab dredger in terms of ship hull, turntable and boom, establish the whole rigid-flexible coupling model by Pro/E, ANSYS and ADAMS. Particularly, attempt a new method to model dredger cable system, and realize the fast parametric modeling of cable system.(3) By using the software Fluent on the ANSYS Workbench platform, simulate the clamshell to calculate the resistance of the clamshell moving in the water and research the relationship between the resistance value and relative velocity.(4) Considering the characteristics of grab dredger clamshell underwater work, fluid mechanics simulation result loads to grab dredger dynamic model and use ADAMS to simulate grab dredger clamshell and research dynamic load and load characteristics in different working conditions. Provide reference for structural design of grab dredger.