Summarized in the paper are the author's studies on incipient motion of sediment in recent 40 years. In addition to the forces of gravity, drag and lift, the cohesive force and the additional static pressure are i...Summarized in the paper are the author's studies on incipient motion of sediment in recent 40 years. In addition to the forces of gravity, drag and lift, the cohesive force and the additional static pressure are important for fine particles. The relations between three stages of incipient motion are defined by use of instantaneous velocity. Formulas for initial velocity and critical shear stress are given and overall verified by the author's and others' experimental data.展开更多
Symmetrical passive running of a simple spring model is commonly used to predict the locomotion of real animals and develop the design strategies for legged systems. If the initial conditions for running can be found ...Symmetrical passive running of a simple spring model is commonly used to predict the locomotion of real animals and develop the design strategies for legged systems. If the initial conditions for running can be found automatically, we can expand the ranges of the model parameters freely. To achieve this objective, we derive an efcient searching procedure based on analysis of the symmetries. Using this process, the desired initial states of the passive running are obtained. Existence of the results reveals that the leg symmetries can be used to generate the symmetrical running. Moreover, the leg forces are associated with the running pattern, implying that we should choose suitable motion for the given model characteristics.展开更多
Based on the kinematic relationship of the drill, drill point and workpiece and the coordinate systems founded,the mathematical models of the drill point wandering motion for the drill initial penetration, i. e. the f...Based on the kinematic relationship of the drill, drill point and workpiece and the coordinate systems founded,the mathematical models of the drill point wandering motion for the drill initial penetration, i. e. the formulae for the drill point center locus, hole shape and cutting edge locus, are established. According to these formulae the hole shape to be made is simulated and analyzed. It is verified that the bending chatter of the drill during the drill penetrating is the main cause to form a polygon like hole.展开更多
文摘Summarized in the paper are the author's studies on incipient motion of sediment in recent 40 years. In addition to the forces of gravity, drag and lift, the cohesive force and the additional static pressure are important for fine particles. The relations between three stages of incipient motion are defined by use of instantaneous velocity. Formulas for initial velocity and critical shear stress are given and overall verified by the author's and others' experimental data.
文摘Symmetrical passive running of a simple spring model is commonly used to predict the locomotion of real animals and develop the design strategies for legged systems. If the initial conditions for running can be found automatically, we can expand the ranges of the model parameters freely. To achieve this objective, we derive an efcient searching procedure based on analysis of the symmetries. Using this process, the desired initial states of the passive running are obtained. Existence of the results reveals that the leg symmetries can be used to generate the symmetrical running. Moreover, the leg forces are associated with the running pattern, implying that we should choose suitable motion for the given model characteristics.
文摘Based on the kinematic relationship of the drill, drill point and workpiece and the coordinate systems founded,the mathematical models of the drill point wandering motion for the drill initial penetration, i. e. the formulae for the drill point center locus, hole shape and cutting edge locus, are established. According to these formulae the hole shape to be made is simulated and analyzed. It is verified that the bending chatter of the drill during the drill penetrating is the main cause to form a polygon like hole.
