Using the basic solutions of a single crack and a single inclusion, and making use of the principle of linear superposition of elastic mechanics, the interaction problem between a planar crack and a flat inclusion in ...Using the basic solutions of a single crack and a single inclusion, and making use of the principle of linear superposition of elastic mechanics, the interaction problem between a planar crack and a flat inclusion in an elastic solid is studied. The problem is reduced to solve a set of standard Cauchy-type singular equations. And the stress intensity factors at points of crack and inclusion were obtained. Besides, the singularity for the horizontal contact of crack and inclusion was analyzed. The calculating model put forward can be regarded as a new technique for studying the crack and its expanding caused by inclusion lip. Then several numerical examples are given.展开更多
Robot-assisted technology has been increasingly employed in the therapy of post stroke patients to deliver high-quality treatment and alleviate therapists5 burden.This paper introduces a novel parallel end traction ap...Robot-assisted technology has been increasingly employed in the therapy of post stroke patients to deliver high-quality treatment and alleviate therapists5 burden.This paper introduces a novel parallel end traction apparatus(PETA)to supplement equipment selection.Considering the appearance and performance of the PETA,two types of special five-bar linkage mechanisms are selected as the potential configurations of the actuation execution unit because of their compact arrangement and parallel structure.Kinematic analysis of each mechanism,i.e.,position solutions and Jacobian matrix,is carried out.Subsequently,a comparative study between the two mechanisms is conducted.In the established source of nondimensional parameter synthesis,the singularity,maximum continuous workspace,and performance variation trends are analyzed.Based on the evaluation results,the final scheme with determined configuration and corresponding near-optimized non-dimensional parameters is obtained.Then,a prototype is constructed.By adding a lockable translational degree of freedom in the vertical direction,the PETA can provide 2D planar exercise and 3D spatial exercise.Finally,a control system is developed for passive exercise mode based on the derived inverse position solution,and preliminary experiments are performed to verify the applicability of the PETA.展开更多
文摘Using the basic solutions of a single crack and a single inclusion, and making use of the principle of linear superposition of elastic mechanics, the interaction problem between a planar crack and a flat inclusion in an elastic solid is studied. The problem is reduced to solve a set of standard Cauchy-type singular equations. And the stress intensity factors at points of crack and inclusion were obtained. Besides, the singularity for the horizontal contact of crack and inclusion was analyzed. The calculating model put forward can be regarded as a new technique for studying the crack and its expanding caused by inclusion lip. Then several numerical examples are given.
基金The authors thank Henan Huibo Medical Co.,Ltd.for several useful suggestions on this apparatus.Additionally,this research is funded in part by Beijing Natural Science Foundation(Grant No.3204036)in part by the National Key R&D Program of China(Grant Nos.2018YFB1307004 and 2020YFC2004200)+1 种基金in part by the National Natural Science Foundation of China(Grant No.61903011)in part by the General Program of Science and Technology Development Project of the Beijing Municipal Education Commission(Grant No.KM202010005021).
文摘Robot-assisted technology has been increasingly employed in the therapy of post stroke patients to deliver high-quality treatment and alleviate therapists5 burden.This paper introduces a novel parallel end traction apparatus(PETA)to supplement equipment selection.Considering the appearance and performance of the PETA,two types of special five-bar linkage mechanisms are selected as the potential configurations of the actuation execution unit because of their compact arrangement and parallel structure.Kinematic analysis of each mechanism,i.e.,position solutions and Jacobian matrix,is carried out.Subsequently,a comparative study between the two mechanisms is conducted.In the established source of nondimensional parameter synthesis,the singularity,maximum continuous workspace,and performance variation trends are analyzed.Based on the evaluation results,the final scheme with determined configuration and corresponding near-optimized non-dimensional parameters is obtained.Then,a prototype is constructed.By adding a lockable translational degree of freedom in the vertical direction,the PETA can provide 2D planar exercise and 3D spatial exercise.Finally,a control system is developed for passive exercise mode based on the derived inverse position solution,and preliminary experiments are performed to verify the applicability of the PETA.
