Researching On Dynamic Characteristics Of Trunk Mounted Concrete Pump Boom Based On Integrated Vehicle

Trunk mounted concrete pump boom is a multi-section flexible mechanical structure composed of box girder.During the construction process,the boom arms are deployed to form different postures to pour the concrete to the corresponding position.The trunk mounted concrete pump has complex working conditions and many factors affecting the working site.When the trunk mounted concrete pump is working,its long-span boom is vibrated under various excitations,causing fatigue failure of the structural components and vibration of the boom end.If it is too large,the concrete cannot be accurately poured,and the trunk mounted concrete pump is damaged,and the concrete pouring efficiency and the pouring quality are poor.Therefore,it is very important to study the dynamic characteristics of the trunk mounted concrete pump boom and analyze its regularity to provide the company with the first design guidance,suppress the vibration of the concrete pump truck,improve the service life of the trunk mounted concrete pump,save the enterprise cost and improve the construction quality of the trunk mounted concrete pump significance.This paper mainly takes the 52-meter trunk mounted concrete pump with six-arm provided by a certain enterprise as the research object,and divides the trunk mounted concrete pump into a boom system,a pumping system and a simplified chassis system,and considers the overall work of the trunk mounted concrete pump,it is proposed to analyze the independent analysis and interaction of each system.Based on the whole vehicle research,the vibration response and dynamic stress law of the trunk mounted concrete pump boom are studied.The specific research work mainly includes the following aspects:(1)Analyze the various loads received by the trunk mounted concrete pump boom and the chassis,establish the boom coordinate system,calculate the magnitude of the load related to the boom and the chassis,and analyze the load distribution and the action form.(2)According to the basic principle of the working of the pumping system,the working mode of pumping the two cylinders,and the parameters of the pumping system,the general form of the flow velocity of the concrete in the boom pipe,and the force of the concrete in the flow of the boom pipe.(3)The theory of the control volume of the trunk mounted concrete pump boom is proposed.The vibration displacement excitation of the trunk mounted concrete pump boom chassis system under the pumping action of the boom system and the pumping system is studied.It is also the chassis displacement excitation of the trunk mounted concrete pump boom.Concrete flows in the boom pipe,and the load on the trunk mounted concrete pump boom can be obtained by its momentum change.Therefore,it is proposed to regard the boom system as a fluid system containing solids,and to establish the analysis theory of the boom control volume and analyze the boom.The velocity field of the control volume is applied,and the momentum theorem integral form is used to calculate the momentum and momentum moment changes of the boom system,and the force of the boom system to the hinge joint of the chassis is further calculated.The finite element model of the chassis was established,and the chassis was simulated and analyzed by ANSYS to obtain the vibration displacement under the force of the boom system and the pumping system.(4)Study the vibration law of the concrete pump truck boom system under the displacement excitation of the chassis system and the concrete flow load of the boom pipe,and the dynamic stress change of the concrete pump truck boom.The finite element model of the concrete pump truck was established,and the natural frequencies of the concrete pump truck boom and the whole truck were calculated respectively.The vibration law and dynamic stress variation law of the boom frame under the excitation of the chassis and other loads were analyzed by ANSYS.(5)Trunk mounted concrete pump boom test analysis and comparison,verify the analysis theory and technical route.The experiment was carried out on the concrete trunk mounted concrete pump provided by the enterprise.The end vibration displacement of the three typical attitudes of the boom and the dynamic stress of a certain number of measuring points of each section arm were measured.The experimental data were analyzed and processed,and the simulation results were obtained.The comparative analysis of vibration and dynamic stress verified the proposed research method and technical route.