A small hole of 0.9mm in diameter is drilled at the theoretical contact point of the convex tooth flank of the measured gear, and the hole leads throughout to the non-working flank. A stylus glued to the core of trans...A small hole of 0.9mm in diameter is drilled at the theoretical contact point of the convex tooth flank of the measured gear, and the hole leads throughout to the non-working flank. A stylus glued to the core of transformer is put into the hole, and the stylus can freely contact with the meshed concave tooth flank. The transformer is installed on the body of gear to be measured. Rotate the positioning worm slowly after loading, and locate the contact point at the hole of convex tooth flank, the displacement value measured is considered as the deformation of convex tooth. The deformations at the middle and the two ends of tooth breadth for the helical gears with double-circular-cra tooth profile whose modules are 3mm and 4mm respectively are measured in the paper.展开更多
The feedback vertex set (FVS) problem is to find the set of vertices of minimum cardinality whose removal renders the graph acyclic. The FVS problem has applications in several areas such as combinatorial circuit desi...The feedback vertex set (FVS) problem is to find the set of vertices of minimum cardinality whose removal renders the graph acyclic. The FVS problem has applications in several areas such as combinatorial circuit design, synchronous systems, computer systems, and very-large-scale integration (VLSI) circuits. The FVS problem is known to be NP-hard for simple graphs, but polynomi-al-time algorithms have been found for special classes of graphs. The intersection graph of a collection of arcs on a circle is called a circular-arc graph. A normal Helly circular-arc graph is a proper subclass of the set of circular-arc graphs. In this paper, we present an algorithm that takes time to solve the FVS problem in a normal Helly circular-arc graph with n vertices and m edges.展开更多
The rate of electrification in rural areas in Zambia is very low, currently standing at less than 5% despite having abundant flowing water resources. Hydrokinetic technology is an alternative among other promising tec...The rate of electrification in rural areas in Zambia is very low, currently standing at less than 5% despite having abundant flowing water resources. Hydrokinetic technology is an alternative among other promising technologies for rural area electrification because of availability of abundant flowing Rivers and low population in rural settlement. In this paper, the author designed and numerically simulated a circular arc blade hydrokinetic turbine system. The design power for the horizontal axis hydrokinetic turbine was 3 kW at water velocity of 3 m/s with the tip speed ratio of 2.5, angle of attack of 10 degrees and power coefficient of 0.4. In this work, a numerical simulation was employed to characterize and develop the horizontal axis hydrokinetic turbine. The prototype circular arc blade horizontal axis hydrokinetic turbine was tested in one of stream in Zambia and the results were compared with the numerical simulation results.展开更多
为评价齿廓方案的负载传动性能,提升负载传动能力,建立有限元分析(Finite Element Analysis,FEA)仿真模型,揭示了输出端扭转刚度与负载啮合特性的关系。构造三圆弧柔轮齿廓,调整柔轮齿廓的径向变位系数,使柔轮齿廓啮合运动的外包络重叠...为评价齿廓方案的负载传动性能,提升负载传动能力,建立有限元分析(Finite Element Analysis,FEA)仿真模型,揭示了输出端扭转刚度与负载啮合特性的关系。构造三圆弧柔轮齿廓,调整柔轮齿廓的径向变位系数,使柔轮齿廓啮合运动的外包络重叠量最小化,并基于外包络用包络法设计了三圆弧平面齿廓刚轮;在多个横截面内构造径向变位的三圆弧柔轮齿廓,在有限元环境下轴向放样生成柔轮空间齿廓,建立了包含平面齿廓刚轮、空间齿廓柔轮和波发生器外圈的有限元仿真模型;固定刚轮,对柔轮杯底法兰施加不同幅值和转向的负载转矩,仿真计算了啮合力分布与扭转刚度滞回曲线;通过建立啮合齿数与刚度特性的关系,揭示了扭转刚度特性与齿面啮合特性之间的关系。仿真结果表明,啮合齿数与扭转刚度成正相关;使用可测量的扭转刚度迟滞曲线,可以估算啮合齿数等不可测量的啮合特性。展开更多
文摘A small hole of 0.9mm in diameter is drilled at the theoretical contact point of the convex tooth flank of the measured gear, and the hole leads throughout to the non-working flank. A stylus glued to the core of transformer is put into the hole, and the stylus can freely contact with the meshed concave tooth flank. The transformer is installed on the body of gear to be measured. Rotate the positioning worm slowly after loading, and locate the contact point at the hole of convex tooth flank, the displacement value measured is considered as the deformation of convex tooth. The deformations at the middle and the two ends of tooth breadth for the helical gears with double-circular-cra tooth profile whose modules are 3mm and 4mm respectively are measured in the paper.
文摘The feedback vertex set (FVS) problem is to find the set of vertices of minimum cardinality whose removal renders the graph acyclic. The FVS problem has applications in several areas such as combinatorial circuit design, synchronous systems, computer systems, and very-large-scale integration (VLSI) circuits. The FVS problem is known to be NP-hard for simple graphs, but polynomi-al-time algorithms have been found for special classes of graphs. The intersection graph of a collection of arcs on a circle is called a circular-arc graph. A normal Helly circular-arc graph is a proper subclass of the set of circular-arc graphs. In this paper, we present an algorithm that takes time to solve the FVS problem in a normal Helly circular-arc graph with n vertices and m edges.
文摘The rate of electrification in rural areas in Zambia is very low, currently standing at less than 5% despite having abundant flowing water resources. Hydrokinetic technology is an alternative among other promising technologies for rural area electrification because of availability of abundant flowing Rivers and low population in rural settlement. In this paper, the author designed and numerically simulated a circular arc blade hydrokinetic turbine system. The design power for the horizontal axis hydrokinetic turbine was 3 kW at water velocity of 3 m/s with the tip speed ratio of 2.5, angle of attack of 10 degrees and power coefficient of 0.4. In this work, a numerical simulation was employed to characterize and develop the horizontal axis hydrokinetic turbine. The prototype circular arc blade horizontal axis hydrokinetic turbine was tested in one of stream in Zambia and the results were compared with the numerical simulation results.
文摘为评价齿廓方案的负载传动性能,提升负载传动能力,建立有限元分析(Finite Element Analysis,FEA)仿真模型,揭示了输出端扭转刚度与负载啮合特性的关系。构造三圆弧柔轮齿廓,调整柔轮齿廓的径向变位系数,使柔轮齿廓啮合运动的外包络重叠量最小化,并基于外包络用包络法设计了三圆弧平面齿廓刚轮;在多个横截面内构造径向变位的三圆弧柔轮齿廓,在有限元环境下轴向放样生成柔轮空间齿廓,建立了包含平面齿廓刚轮、空间齿廓柔轮和波发生器外圈的有限元仿真模型;固定刚轮,对柔轮杯底法兰施加不同幅值和转向的负载转矩,仿真计算了啮合力分布与扭转刚度滞回曲线;通过建立啮合齿数与刚度特性的关系,揭示了扭转刚度特性与齿面啮合特性之间的关系。仿真结果表明,啮合齿数与扭转刚度成正相关;使用可测量的扭转刚度迟滞曲线,可以估算啮合齿数等不可测量的啮合特性。
