%0 Journal Article %T A Numerical Method of Large-Scale Concrete Displacing Boom Dynamic and Experimental Validation %A Wu Ren %A Yun-xin Wu %A Zhao-wei Zhang %A Wen-ze Shi %J Advances in Mechanical Engineering %D 2014 %I SAGE Publications %R 10.1155/2014/943847 %X Concrete displacing boom is large-scale motion manipulator. During the long distance pouring the postures needs to frequently change. This makes the real-time dynamic analysis and health monitoring difficult. Virtual spring-damper method is adopted to establish the equivalent hydraulic actuator model. Besides boom cylinder joint clearance is taken into account. Then transfer matrix method is used to build the multibody concrete placing boom model by dividing the system into two substructures. Next typical working conditions displacements and accelerations during the pouring process are studied. The results of the numerical method are correct and feasible compared with Recurdyn software and the experimental ones. So it provides reference to the real-time monitoring and structure design for such light weight large scale motion manipulators. 1. Introduction Concrete displacing boom is light weight large movement flexibility manipulator. Until 2013, the longest displacing boom has reached 101 meters. The frequent postures change during pouring process usually leads large vibration. In particular the tip displacement, structure stress and hydraulic actuator force are changing along with different working conditions. So it brings difficulty to boom real-time health monitoring and dynamic analysis. By far the existing researches usually ignore the influence of joint clearance. Besides transfer matrix method has advantages of fast calculation in solving this multibody system dynamics. The traditional researches on multibody manipulator are as follow. Cazzulani et al. studied the dynamics of a 1£¿:£¿3 truck mounted concrete pump truck boom. The vibration suppression method is given to this manipulator. The added tip end mass influence on the natural frequency and vibration was also studied [1]. Lenord et al. built an interdisciplinary 4-section boom flexible nonlinear model. Linear and nonlinear characteristic were simulated by damping optimization. Finally a linear substitute model was adopted [2]. Liu et al. used Lagrange method and have built a commercial truck mounted concrete pump boom model. Then tip displacement was analyzed [3]. Heinze established a hydraulic crane boom model and did the trajectory control by considering the boom friction [4]. The studies of joint clearance are as follows. Shabana et al., Bauchau et al., Nachbagauer et al., and Tian et al. did researches on the absolute nodal coordinate method to calculate flexible nonlinear structure with joint clearance [5¨C8]. Chen et al. have established the nonlinear motion equations of flexible rigid %U http://www.hindawi.com/journals/ame/2014/943847/