In this investigation, a modeling procedure of a telescopic boom of cranes is developed using the absolute nodal coordinate formulation together with the sliding joint constraints. Since telescopic booms are extracted...In this investigation, a modeling procedure of a telescopic boom of cranes is developed using the absolute nodal coordinate formulation together with the sliding joint constraints. Since telescopic booms are extracted and retracted under various operating conditions, the overall length of the boom changes dynamically, leading to the time-variant vibration characteristics. For modeling the telescopic structure of booms, a special care needs to be exercised since the location of the sliding contact point moves Mong the deformable axis of the flexible boom and the solution to a moving boundary problem is required. This issue indeed makes the modeling of the telescopic boom difficult, despite the significant needs for the analysis. It is, therefore, the objective of this investigation to develop a modeling procedure for the flexible telescopic boom by considering the sliding contact condition with the dynamic frictional effect. To this end, the sliding joint constraint developed for the absolute nodal coordinate formulation is employed for describing relative sliding motion between flexible booms, while flexible booms are modeled using the beam element of the absolute nodal coordinate formulation, which allows for modeling the large rotation and deformation of the structure.展开更多
A high‐fidelity multibody‐system dynamic model of the looped tether transportation system(L‐TTS)is proposed in this study to study its large deformation as well as large overall motion.The absolute nodal coordinate...A high‐fidelity multibody‐system dynamic model of the looped tether transportation system(L‐TTS)is proposed in this study to study its large deformation as well as large overall motion.The absolute nodal coordinate formulation(ANCF)‐based gradient‐deficient beam element is employed to establish the accurate model of the two flexible tethers subject to large deformations.The relative movement of climbers along tethers is described by using the sliding joint model based on ANCF.To reduce the collision risks between tethers and climbers,two libration suppression strategies,namely,the decelerated motion of climbers relative to tethers and multiple climbers per tether are investigated in this study.Several numerical simulations not only validate the effectiveness of the two strategies in reducing the collision risks between climbers and tethers,the overall librations of L‐TTS,and the magnitudes of the longitudinal elastic force of tethers,but also verify the good performance of the high‐fidelity model proposed in this study for dynamic simulation of the L‐TTS in microgravity conditions.展开更多
基金supported by Kato Construction Machine Research & Development Promotion Fund
文摘In this investigation, a modeling procedure of a telescopic boom of cranes is developed using the absolute nodal coordinate formulation together with the sliding joint constraints. Since telescopic booms are extracted and retracted under various operating conditions, the overall length of the boom changes dynamically, leading to the time-variant vibration characteristics. For modeling the telescopic structure of booms, a special care needs to be exercised since the location of the sliding contact point moves Mong the deformable axis of the flexible boom and the solution to a moving boundary problem is required. This issue indeed makes the modeling of the telescopic boom difficult, despite the significant needs for the analysis. It is, therefore, the objective of this investigation to develop a modeling procedure for the flexible telescopic boom by considering the sliding contact condition with the dynamic frictional effect. To this end, the sliding joint constraint developed for the absolute nodal coordinate formulation is employed for describing relative sliding motion between flexible booms, while flexible booms are modeled using the beam element of the absolute nodal coordinate formulation, which allows for modeling the large rotation and deformation of the structure.
基金This study was supported in part by the National Natural Science Foundation of China(Grant No.11902159)the Natural Science Foundation of Jiangsu Province of China(Grant No.BK20190390)It was also supported in part by the China Postdoctoral Science Foundation(Grant No.2019M661849).
文摘A high‐fidelity multibody‐system dynamic model of the looped tether transportation system(L‐TTS)is proposed in this study to study its large deformation as well as large overall motion.The absolute nodal coordinate formulation(ANCF)‐based gradient‐deficient beam element is employed to establish the accurate model of the two flexible tethers subject to large deformations.The relative movement of climbers along tethers is described by using the sliding joint model based on ANCF.To reduce the collision risks between tethers and climbers,two libration suppression strategies,namely,the decelerated motion of climbers relative to tethers and multiple climbers per tether are investigated in this study.Several numerical simulations not only validate the effectiveness of the two strategies in reducing the collision risks between climbers and tethers,the overall librations of L‐TTS,and the magnitudes of the longitudinal elastic force of tethers,but also verify the good performance of the high‐fidelity model proposed in this study for dynamic simulation of the L‐TTS in microgravity conditions.
