Vibration of Visco-Elastic Parallelogram Plate with Parabolic Thickness Variation

The main objective of the present investigation is to study the vibration of visco-elastic parallelogram plate whose thickness varies parabolically. It is assumed that the plate is clamped on all the four edges and that the thickness varies parabolically in one direction i.e. along length of the plate. Rayleigh-Ritz technique has been used to determine the frequency equation. A two terms deflection function has been used as a solution. For visco-elastic, the basic elastic and viscous elements are combined. We have taken Kelvin model for visco-elasticity that is the combination of the elastic and viscous elements in parallel. Here the elastic element means the spring and the viscous element means the dashpot. The assumption of small deflection and linear visco-elastic properties of “Kelvin” type are taken. We have calculated time period and deflection at various points for different values of skew angles, aspect ratio and taper constant, for the first two modes of vibration. Results are supported by tables. Alloy “Duralumin” is considered for all the material constants used in numerical

Three-dimensional analysis of natural convection in nanofluid-filled parallelogrammic enclosure opened from top and heated with square heater

A numerical study based on the finite volume method has been performed to study the three-dimension natural convection in a parallelogrammic top side opened cavity filled nanofluid with partially heated square at the bottom side.Results are obtained for different governing parameters such as nanoparticle concentration (φ) from 0 to 0.05,inclination angle of the back and front walls (α) from 5° to 75°,Rayleigh number from 10^3 to 10^5,and length of heater changer from 0.1 to 1.The main finding from the obtained result showed that the inclination angle and nanoparticle volume fraction affect the flow structure and enhance the heat transfer.

Crack Quantification of Bolted Joints by Using a Parallelogram Eddy Current Array Sensing Film

Crack monitoring at the bolt hole edge is one of the important focuses of aircraft structural health monitoring.In this study,a novel eddy current sensing film based on a parallelogram coil array is developed to quantitatively monitor the crack characteristics near the bolt hole with fewer layers and coils,compared with the existing methods.The parallelogram coil array configuration is designed and optimized to improve the quantitative monitoring ability of the crack.A 3×3 parallelogram coil array is used to quantify the crack parameters of aluminum bolted joints.Finite element simulation and experiments show that the proposed parallelogram coil array could not only accurately and quantitatively identify the crack angle at the edge of the bolt hole,but also track the crack length along the radial direction of the bolt hole and the depth along the axial direction.

Proposal for Offshore Wind Farm with Triangle-Coupled Movable Parallelogram Buoyancy Structure for the High Seas

We are responsible for providing energy and food resources for our next generation.After more than 20 years of research,the author has confirmed that the VAWT with flip-up mechanism can maintain rotation without the brake,even in strong winds.Experiments have shown that the triangularly coupled movable parallelogram buoyancy structure makes it easy to maintain the verticality of the wind turbine tower even under large waves.Furthermore,as a result of studying the connection between the HAWT(horizontal axis wind turbine)and the movable parallelogram buoyancy structure of the triangular connection,the feasibility was confirmed.The only way for all people in the world to secure energy and food fairly is to look for the remaining areas such as the high seas.The author would like to propose the use of the high seas to combat global hunger,which is likely to be a global problem in the future.

Thermal Effect on Vibration of Parallelogram Plate of Bi-Direction Linearly Varying Thickness

In this paper, the effect of thermal gradient on the vibration of parallelogram plate with linearly varying thickness in both direction having clamped boundary conditions on all the four edges is analyzed. Thermal effect on vibration of such plate has been taken as one-dimensional distribution in linear form only. An approximate but quiet convenient frequency equation is derived using Rayleigh-Ritz technique with a two-term deflection function. The frequencies corresponding to the first two modes of vibration of a clamped parallelogram plate have been computed for different values of aspect ratio, thermal gradient, taper constants and skew angle. The results have been presented in tabular forms. The results obtained in this study are reduced to that of unheated parallelogram plates of uniform thickness and have generally been compared with the published one.

The First Eccentric Zagreb Index of Linear Polycene Parallelogram of Benzenoid

Let G = (V,E) be a graph, where V(G) is a non-empty set of vertices and E(G) is a set of edges, e = uv∈E(G), d(u) is degree of vertex u. Then the first Zagreb polynomial and the first Zagreb index Zg1(G,x) and Zg1(G) of the graph G are defined as Σuv∈E(G)x(du+dv) and Σe=uv∈E(G)(du+dv) respectively. Recently Ghorbani and Hosseinzadeh introduced the first Eccentric Zagreb index as Zg1*=Σuv∈E(G)(ecc(v)+ecc(u)), that ecc(u) is the largest distance between u and any other vertex v of G. In this paper, we compute this new index (the first Eccentric Zagreb index or third Zagreb index) of an infinite family of linear Polycene parallelogram of benzenoid.

以ADAMS为平台的旋挖钻机变幅机构变幅油缸举升力仿真分析

介绍旋挖钻机变幅机构的主流结构形式及其工作原理,并借助Pro/E建立变幅机构的三维模型,再导入ADAMS建立动力学仿真模型。在ADAMS虚拟环境中,对变幅机构两组变幅油缸在不同运动顺序下的举升力分别进行仿真,给出两组变幅油缸举升力的仿真曲线,并分析仿真结果,得出对旋挖钻机变幅机构设计具有指导性的一些结论。

具有平行四边形截面的杆类结构波动特性分析

超声导波无损检测技术具有高效、快捷、灵敏等特点,应用前景广泛。复杂结构的无损检测方案,需要根据结构中超声导波传播特性分析结果进行优化选取。针对平行四边形截面杆,采用同时满足平行四边形域基本方程及斜边边界条件的斜坐标系,建立了完整的平行四边形杆的波动力学方程。采用分向半解析法,计算得到了平行四边形杆中超声导波的频散曲线,并分别研究了斜坐标系角度、对角线之比和邻边边长之比对纵向、扭转模态频散特性的影响规律。最后,通过导波激励、接收实验,验证了计算所得结论的正确性。

GPS导航系统中的地图匹配算法

传统算法对于复杂路况的匹配正确率较低,为此,提出一种适合于交通网络拓扑结构变化的动态平行四边形匹配算法。利用权值选出匹配路段,并将全球定位系统(GPS)轨迹点投影到匹配路段上,在交叉路口以平行四边形匹配准则消除车辆轨迹点沿道路方向的误差,通过动态偏差更新,解决卫星换星、大气云层遮挡、多路径效应等因素造成的偏差问题。引入该算法的GPS车载系统在合肥市实地跑车实验结果表明,其对于复杂路况仍能进行正确匹配,真实再现车辆行驶情况。

一种多功能拟静力试验装置

结构抗震的试验研究是结构抗震理论的重要组成部分。如何更加真实地模拟结构构件的压、弯、剪等多种受力性能以及解决试验加载方式和试验装置的不足等问题,一直困扰着广大土木工作者。为了提高实验室的科研教学能力和实验室使用效益,课题组自行设计、加工制作了一种多功能拟静力试验装置,该试验加载装置及设备主要采用反力墙、大型门架构架,液压伺服加载控制系统及竖向加载系统。通过科学、合理的设计,使得该装置不仅可以完成压弯剪型试验,还可完成剪切型破坏形式的大型试验。同时,该装置安装简单,灵活性强,占用实验场地少,节省空间。其中,装置的竖向加载系统由自行设计、制作的竖向稳压系统和水平滚动装置组成。相比其他传统竖向加载装置,利用杠杆放大及等压原理设计制作的杠杆放大式稳压装置,更好地解决了结构构件试验竖向稳定加载问题。利用这种多功能拟静力试验装置,已完成多项压弯型及剪切型大型抗震试验项目,试验效果理想、数据可靠,解决了部分试验能力不足问题,节约了大量资金。

平行四边形机构在抽油杆定率传输中的应用

系统地论述了平行四边形机构在抽油杆自动检测生产线上用于抽油杆定率（定时定量）传输的关键技术问题：１．自由度分析，保证实现确定的运动；２．运动的协调性，保证实现准确、可靠的定率传输；３．受力分析，为结构设计和优化计算提供力学依据；４．上、下杆的衔接，保证生产线的正常运行；５．参数优化计算，保证在满足结构要求的条件下机构受力最好。平行四边形机构的应用已在生产中获得成功。

Error Modeling and Sensitivity Analysis of a Parallel Robot with SCARA(Selective Compliance Assembly Robot Arm) Motions

Parallel robots with SCARA（selective compliance assembly robot arm） motions are utilized widely in the field of high speed pick-and-place manipulation. Error modeling for these robots generally simplifies the parallelogram structures included by the robots as a link. As the established error model fails to reflect the error feature of the parallelogram structures, the effect of accuracy design and kinematic calibration based on the error model come to be undermined. An error modeling methodology is proposed to establish an error model of parallel robots with parallelogram structures. The error model can embody the geometric errors of all joints, including the joints of parallelogram structures. Thus it can contain more exhaustively the factors that reduce the accuracy of the robot. Based on the error model and some sensitivity indices defined in the sense of statistics, sensitivity analysis is carried out. Accordingly, some atlases are depicted to express each geometric error’s influence on the moving platform’s pose errors. From these atlases, the geometric errors that have greater impact on the accuracy of the moving platform are identified, and some sensitive areas where the pose errors of the moving platform are extremely sensitive to the geometric errors are also figured out. By taking into account the error factors which are generally neglected in all existing modeling methods, the proposed modeling method can thoroughly disclose the process of error transmission and enhance the efficacy of accuracy design and calibration.

新型简易双层立体停车库

简述一种简易双层立体停车库的工作原理和设计要点。上层车辆出入库采用平行四边形机构,下层车辆出入库采用小车自行走横移方式。上下层车辆出入库时均与道路轴线平行,故无需倒车入库,节省了出入库空间和时间,使在狭窄通道上构建立体停车库成为可能。下层停车与否不影响上层车辆的出入库。

Research on Oil/Gas In-pipe Inspection Robot

A new type of in-pipe mobile robot was designed and developed on the basis of w heel in-pipe robot and crawler in-pipe robot. The three sets of driving wheels circumferentially 120° apart in the cross section, both front and rear driving wheels are distributed on the same parallelogram mechanis m. The driving motor drives the three sets of driving wheels by worm couple, the regulating motor makes the three sets of driving wheels push against the pipe inwall with stable and adequate pressing force by the ball screw pair and p ressure sensor, so the in-pipe robot can provide adequate and stable traction force. The robot mechanism is simple and sm all in size and work reliably . It is particularly suitable to the pipe with diameter 400～650 mm.

On Tilings of Quadrants and Rectangles and Rectangular Pattern

The problem of tiling rectangles by polyominoes generated large interest. A related one is the problem of tiling parallelograms by twisted polyominoes. Both problems are related with tilings of (skewed) quadrants by polyominoes. Indeed, if all tilings of a (skewed) quadrant by a tile set can be reduced to a tiling by congruent rectangles (parallelograms), this provides information about tilings of rectangles (parallelograms). We consider a class of tile sets in a square lattice appearing from arbitrary dissections of rectangles in two L-shaped polyominoes and from symmetries of these tiles about the first bisector. Only translations of the tiles are allowed in a tiling. If the sides of the dissected rectangle are coprime, we show the existence of tilings of all (skewed) quadrants that do not follow the rectangular (parallelogram) pattern. If one of the sides of the dissected rectangle is 2 and the other is odd, we also show tilings of rectangles by the tile set that do not follow the rectangular pattern. If one of the sides of the dissected rectangle is 2 and the other side is even, we show a new infinite family of tile sets that follows the rectangular pattern when tiling one of the quadrants. For this type of dis-section, we also show a new infinite family that does not follow the rectangular pattern when tiling rectangles. Finally, we investigate more general dissections of rectangles, with. Here we show infinite families of tile sets that follow the rectangular pattern for a quadrant and infinite families that do not follow the rectangular pattern for any quadrant. We also show, for infinite families of tile sets of this type, tilings of rectangles that do not follow the rectangular pattern.

An Upper Limb Exoskeleton Design for Reduced Gravity Training of Astronauts

A wearable passive exoskeleton is proposed for reduced gravity astronauts training.The main component unit of the proposed robotic exoskeleton is the spring-based parallelogram mechanism which can passively balance any proportion of the gravity load acting on it through designing an appropriate stiffness of the spring or adjusting the install position of the spring.A conceptual exoskeleton model capable of gravity compensation for upper limbs applying to such technology is designed and the corresponding simulation is presented,in which the muscle activations are collected to show the effectiveness of the design.

Vibration Analysis of Fetching Carton Mechanism of Square Carpets Packaging

In this paper,according to the cantilever beam of fetching carton mechanism in square packaging machine, considering the impact of motion of air cylinder on it,its dynamics model and finite element model are built by using ANSYS. This paper not only acquires the deformation distribution,stress distribution and natural frequency of the cantilever beam in the static state; but also gets the dynamic response curve in the maximum deformation and the dynamic stress response curve in the near of the maximum stress during the motion of air cylinder. Result shows that no matter static state or dynamic state,deformation of the cantilever in the fetching carton mechanism is acceptable. The design of mechanism is reliable and its motion is also stable; no resonance can occur on the cantilever beam.

Some Extensions on Numbers

My previous work dealt finding numbers which relatively prime to factorial value of certain number, high exponents and also find the way for finding mod values on certain number’s exponents. Firstly, I retreat my previous works about Euler’s phi function and some works on Fermat’s little theorem. Next, I construct exponent parallelogram to find coherence numbers of Euler’s phi functioned numbers and apply to Fermat’s little theorem. Then, I test the primality of prime numbers on Pascal’s triangle and explore new ways to construct Pascal’s triangle. Finally, I find the factorial value for certain number by using exponent triangle.

Higher Order Strongly Biconvex Functions and Biequilibrium Problems

In this paper, we introduce and study some new classes of biconvex functions with respect to an arbitrary function and a bifunction, which are called the higher order strongly biconvex functions. These functions are nonconvex functions and include the biconvex function, convex functions, and k-convex as special cases. We study some properties of the higher order strongly biconvex functions. Several parallelogram laws for inner product spaces are obtained as novel applications of the higher order strongly biconvex affine functions. It is shown that the minimum of generalized biconvex functions on the k-biconvex sets can be characterized by a class of equilibrium problems, which is called the higher order strongly biequilibrium problems. Using the auxiliary technique involving the Bregman functions, several new inertial type methods for solving the higher order strongly biequilibrium problem are suggested and investigated. Convergence analysis of the proposed methods is considered under suitable conditions. Several important special cases are obtained as novel applications of the derived results. Some open problems are also suggested for future research.

Parallelogram 3d-4f-5d heterometallic clusters based on trilacunary tungstoantimonates with excellent proton conductivity

Two 3d-4f-5d heterometallic cluster-containing polyoxometalates,formulated as Na_(22){(SbW_(9)O_(33))_(4)[La_(3)W_(6)MO_(18)(H_(2)O)_(8)(CH_(3)COO)_(4)]_(2)}·nH_(2)O(abbreviated as La_(6)M_(2),M=Co/Mn)were synthesized and structurally characterized.Single-crystal X-ray diffraction analyses reveal that the polyanions of La_(6)Co_(2)and La_(6)Mn_(2)consist of the uncommon 3d-4f-5d clusters{La_(6)W_(12)Co_(2)}and{La_(6)W_(12)Mn_(2)},which are encapsulated by four trilacunary Keggin tungstoantimonates to form the parallelogram-shaped title compounds.Additionally,the polyanions can be extended into a two-dimensional(2D)frame by the linkage of peripheral Na+ions.The inner space of the 2D layer was filled with water molecules and thus an H-bonded network was formed,which is expected to exhibit a fascinating proton conductivity.The study of water-assisted proton conduction demonstrated that La_(6)Co_(2)and La_(6)Mn_(2)were temperature-and humiditydependent proton conductors,respectively,and the proton conductivities could reach 1.3×10^(-2)and 2.3×10^(-2)S/cm at 65℃and 90%RH conditions.