The differences between the formation processes of lab backfill samples and field backfill were analysed. An improved sampling mold, containing an outer box shell and inner sampling mold, was put forward. The new and ...The differences between the formation processes of lab backfill samples and field backfill were analysed. An improved sampling mold, containing an outer box shell and inner sampling mold, was put forward. The new and traditional test molds were applied to make subsequent-backfill samples of Yong-ping Copper Mine. The observation of mass fraction and theory analysis of settlement and distribution of tailing particles were carried out. The research results show that the magnitude of the strength of the backfill forming in new mold is lower than that of backfill forming in traditional mold, and the biggest gap amounts to 36%.展开更多
Luffing mechanism is a key component of the construction machinery.This paper proposes a two degree of freedom(2-DOF)luffing mechanism,which has one more pair of driving cylinders than the single DOF luffing mechanism...Luffing mechanism is a key component of the construction machinery.This paper proposes a two degree of freedom(2-DOF)luffing mechanism,which has one more pair of driving cylinders than the single DOF luffing mechanism,to improve the performance of the machinery.To establish the dynamic model of the 2-DOF luffing mechanism,firstly,we develop a hierarchical method to deduce the Jacobian matrix and Hessian matrix for obtaining the kinematics equations.Subsequently,we divide the luffing mechanism into six bodies considering actuators,and deduce the kinetic equations of each body by the Newton-Euler method.Based on the dynamic model,we simulate the luffing process.Finally,a prototype is built on a pile driver to validate the model.Simulations and experiments show that the dynamic model can reflect the dynamic properties of the proposed luffing mechanism.And the control strategy that the front cylinders retract first shows better mechanical behavior than the other two control strategies.This research provides a reference for the design and application of 2-DOF luffing mechanism on construction machinery.The modeling approach can also be applied to similar mechanism with serial closed kinematic chains,which allows to calculate the dynamic parameters easily and exactly.展开更多
基金Project(2010CB732004) Supported by the National Basic Research Program of ChinaProject(50934006) supported by the Key Project of Science and Technology of Shanghai+1 种基金 ChinaProject(CX2012B073) supported by Doctoral Candidates' Scientific Research Innovation Program of Hunan Province, China
文摘The differences between the formation processes of lab backfill samples and field backfill were analysed. An improved sampling mold, containing an outer box shell and inner sampling mold, was put forward. The new and traditional test molds were applied to make subsequent-backfill samples of Yong-ping Copper Mine. The observation of mass fraction and theory analysis of settlement and distribution of tailing particles were carried out. The research results show that the magnitude of the strength of the backfill forming in new mold is lower than that of backfill forming in traditional mold, and the biggest gap amounts to 36%.
基金Project(2015B020238014)supported by the Science and Technology Program of Guangdong Province,China。
文摘Luffing mechanism is a key component of the construction machinery.This paper proposes a two degree of freedom(2-DOF)luffing mechanism,which has one more pair of driving cylinders than the single DOF luffing mechanism,to improve the performance of the machinery.To establish the dynamic model of the 2-DOF luffing mechanism,firstly,we develop a hierarchical method to deduce the Jacobian matrix and Hessian matrix for obtaining the kinematics equations.Subsequently,we divide the luffing mechanism into six bodies considering actuators,and deduce the kinetic equations of each body by the Newton-Euler method.Based on the dynamic model,we simulate the luffing process.Finally,a prototype is built on a pile driver to validate the model.Simulations and experiments show that the dynamic model can reflect the dynamic properties of the proposed luffing mechanism.And the control strategy that the front cylinders retract first shows better mechanical behavior than the other two control strategies.This research provides a reference for the design and application of 2-DOF luffing mechanism on construction machinery.The modeling approach can also be applied to similar mechanism with serial closed kinematic chains,which allows to calculate the dynamic parameters easily and exactly.
