Research On Operation Stability Of Concrete Pump Truck

In recent years,with the rapid economic development and increased investment in infrastructure construction,concrete pump trucks have become very important equipment in construction due to their many advantages.After the pump truck arrives at the construction area and completes the deployment of the outrigger part and the boom system,the concrete material can be poured,which simplifies the concrete pouring process and shortens the time required for concrete pumping and pouring.In order to meet various construction operating environments,the pump truck is not only required to meet the distribution operation under full support conditions,but also to meet the distribution operation under special conditions.The stability of the concrete pump truck is a very important safety performance index.The operation stability during the pumping process directly affects its operation performance and construction safety.The stability of the concrete pump truck is discussed and studied in combination with the subject.Firstly,the basic structure of the concrete pump truck is briefly summarized,and the trajectory of the center of gravity and the static stability coefficient of the concrete pump truck are analyzed.The flow state and rheological properties of concrete in the conveying pipe under pumping pressure are studied,and the flow process of concrete is equivalent to the flow of Bingham body in the pipe.According to the empirical formula of pressure loss,the steady-state excitation model of concrete in the pumping stage and the reversing stage is established,and the dynamic stability coefficient is proposed as the evaluation index of the stability change of the whole machine during the operation of the pump truck.Secondly,the rigid body dynamics model of the concrete pump truck including the boom system,the slewing base and the outrigger parts is established with the help of ADAMS software,and the dynamic simulation analysis is carried out on the process of the boom retracting from the horizontal posture in turn,and the retracting process is obtained.The change curve of the displacement and speed of the center of mass of each boom and the stroke of the corresponding boom luffing cylinder.Then import the 3D model into Hyper Works software for simplification and geometric cleaning,and establish a finite element model of the horizontal attitude of the whole vehicle boom.The natural frequency and corresponding vibration shape of the whole vehicle are obtained through modal analysis,and the pumping pressure and pumping frequency that make the boom end amplitude larger are selected as the research objects,and the influence of the boom end vibration on the stability of the whole machine is discussed.Finally,the neutral file of each boom is imported into ADAMS software,and the rigid-flexible coupling dynamics model of the whole vehicle is established.On the basis of the static stability of the concrete pump truck,considering the pulsating impact formed by the concrete flowing in the distribution pipe and the double oil cylinder circulating feeding of the pumping system during the pumping operation,the vibration of the boom caused by the stability of the whole pump truck is considered.Influence.The dynamic change process of the whole vehicle stability when the azimuth angle of the boom is 45°,90°,130° and 180° under the condition of full support,unilateral support and V-shaped support of the pump truck is discussed.The changing law of the dynamic stability coefficient of the pump truck is obtained.The dynamic stability coefficient of the concrete pump truck model in this paper is 1.239 when the boom orientation is 90° under the unilateral support condition,and 1.210 when the boom orientation is 180° under the V-shaped support condition.Overturning line overturned.Under the above three typical support conditions,the dynamic stability coefficient is reduced by about 15.17% compared with the static stability coefficient.