管内检测机器人在弯管处的通过性能研究

对管内检测机器人在弯管处的通过性问题进行了研究。从空间几何体应满足的几何关系和力学平衡两方面条件出发,对单节机器人在弯管内的运动作了分析,建立了机器人通过弯管的数学模型,并研究了模型的计算方法。通过算例计算,得出了单节机器人的运动轨迹和各运动轮上的弹簧伸缩量,并根据机器人在弯管内的尺寸限制,求得了机器人通过弯管的最大直径。算例证明了本模型得到的机器人运动轨迹平滑,解决了已有模型得到的轨迹存在间断点的问题,为机器人尺寸设计和后续研究提供了理论基础。     

弯管应力分析及结构研究

通过对弯管内流体应力的理论分析与计算，探讨了利用流体动力学求解弯管应力的方法和对弯管结构的研究。通过有限差分法，获得了流体作用下的弯管最终的应力分布特性，达到了为弯管设计和制造提供参考的目的。整个计算程序在有限元软件ANSYS平台上编译进行，计算过程简洁、快速、符合复杂的工程设计要求。计算结果表明，文中提出的计算方法是可行的、有效的。同时，对弯管的结构进行了探讨，讨论了弯管、流体各参数的变化对弯管应力的影响，得出了一些有价值的结论。     

一种弯管管道机器人驱动模块关键结构设计及其运动仿真

通过理论计算推导出关于弯管机器人驱动模块在设计过程中,模块长度、蠕动步距及蠕动防倾倒设计和弯管直径、曲率半径的结构数值关系。根据此数值关系对驱动模块进行设计,然后运用SolidWorks软件对所设计的驱动模块进行建模,再利用ADAMS软件对该驱动模块在标准的弯管中进行运动学仿真,得到此驱动模块在弯管运动时的位移、速度曲线图,验证所得数值关系对于弯管机器人驱动模块设计的可行性。进一步得出结论,此数值关系在弯管机器人驱动模块的长度、支撑脚的长度设计,以及驱动模块在弯管中运动干涉验证具有可行性,为此类型的弯管机器人投入实际生产和后续的弯管机器人整体的自动化设计研究,奠定了一定的基础。     

圆弧型弹性弯管频率特性的有限元分析

弹性弯管在谐振式直接质量流量传感器中起着重要的作用.研究结果表明圆弧型弯管在敏感单元中的作用较大.利用所建立的有限元模型,这里,对圆弧型弹性弯管一、二阶频率特性进行了详细研究.基于仿真计算结果,得到了圆弧型弹性弯管频率特性的一般规律.为谐振式直接质量流量传感器设计合理的弹性弯管结构提供了若干理论依据.     

含内局部减薄缺陷高温弯管蠕变极限载荷及其安全评定

根据P91材料高温等时应力应变本构关系,对高温含内局部减薄缺陷弯管的蠕变极限载荷进行了研究。研究表明,高温蠕变极限载荷在蠕变初期急剧下降,之后下降趋缓,该现象反映了高温下材料蠕变劣化过程。不同应变准则下蠕变极限载荷变化规律一致。根据有限元计算结果,提出了与蠕变时间无关的蠕变极限载荷计算方法,得到了含内局部减薄缺陷高温弯管的安全评定方法。     

用弯管测流量的实验分析

一、引言由于国外对用弯管流量计测流量的探讨,目前对弯管内流体的的流态的的理论分析正在逐步完善。但弯管流量计是否能正常地应用在工业生产中;对弯管的设计制造应该有哪些具体要求;在实际应用中弯管测得的结果与实际结果是否相一致,这都需要我们进一步研究,这也是本文所要探讨的内容。二、理论简析流过弯管的流体,在弯曲部分的任意一个园截面上的动量矩大体是相同的。当流体流过弯头时将产生一个离心力,此离心力导     

90°厚壁弯管的应力分析与试验研究

应用ANSYS软件对受内压作用下的大型厚壁弯管进行了应力计算和分析,从而得到该弯管模型的应力分布规律,并结合相应的试验数据进行对比分析,验证了有限元分析结果的可靠性。     

液流冲击作用下的管道振动特性研究

研究了弯管在阀门快速开启过程的振动现象,对流体选用S-A(Spalart-AIlmaras)湍流模型进行了流动模拟,建立了弯管和流体的有限元模型;对阀门进行流固耦合仿真,分析研究了三种不同流速下的弯管振动情形,并绘制了相关节点的位移-时间曲线.结果表明,随着弯管内流体的流速增大,弯管所受应力增大,弯管振动也更激烈.     

大型石化设备底部弯管壁厚的设计

介绍一种带内压和管载的大型石化设备底部弯管壁厚设计、计算、校核方法。以某环氧乙烷反应器为例,从三个截面出发,设计、计算、校核了弯管的壁厚。采用数值分析的方法,对某有管载的环氧乙烷反应器在设计工艺条件下的应力状况进行分析,得到应力分布结果,并将得到的结果与解析计算的结果进行对比,证明解析法的可行性和正确性。     

气体发动机进气管流动特性分析

为研究气体发动机进气管内流体流动特性,以某型气体发动机的进气管道为研究对象,利用Fluent软件对预处理好的三维模型进行仿真计算,得到混合均匀性分布情况及进气管中的流场分布。对进气管中的流场进行分析,结果表明:混合器结构和弯管曲率对进气管内压力分布有着重要影响,进而影响各缸均匀性。对混合器和弯管结构参数进行优化,可使各缸进气均匀性得到改善。     

小型螺旋轮式管道机器人设计

针对管道内径为Ф100mm的微小型管道检测机器人研究,提出了基于螺旋推进原理的微小型管道机器人的解决方案。新型的旋转体和保持体结构的设计,使此管道机器人具有较大的牵引力和移动速度。机器人采用节段式设计,使得其在体积微小的同时,具有强大的功能扩展性。本文介绍了螺旋推进管道机器人的组成及工作原理,对机器人的机械结构进行了设计,并且分析了其在弯管内的几何与运动约束条件。     

肘形进水流道优化设计与数值计算

为了提高泵站进水流道的设计水平,对应用最为广泛的肘形进水流道的型线进行了数学建模,并采用高级程序设计语言Visual Basic对工程图形处理软件AutoCAD进行二次开发,形成基于流道设计参数的优化设计软件,能够快速进行流道型线的绘制,并能使流道的型线自动符合流速渐变的原则.同时结合三维紊流数值模拟技术和流道的模型试验对流道的水力性能进行检验.通过工程实例说明,该流道设计方法快速、可靠,所设计的肘形进水流道具有出口流态较好、水力损失较小的优点.     

Automated in-vitro testing of orthopaedic implants: a case study in shoulder joint replacement

This investigation presents the design and preliminary validation of a single station simulator with biaxial motion and loading designed to mimic the kinematics of the glenohumeral joint during arm abduction in the scapular plane. Although the design of the glenoid holder allows the glenoid component to translate in all three axes, it is primarily loaded axially, which brings it into contact with the oscillating humeral head, but is also loaded superiorly to simulate common subluxation of the humeral head. Simulating arm abduction in the scapular plane simplifies component alignment and removes the need for anterior-posterior loading, thereby creating a stable joint without the need to simulate capsular constraints. In this more physiologically accurate simulator design, the load and motion profiles influence the contact kinematics, but the wear path is ultimately determined by the conformity and constraint designed into the bearing couple. The wear data are determined and correlated with clinically retrieved glenoid components, as well as previously reported in-vitro studies, thus verifying use of the simulator in testing alternative materials and designs. The key design features, as well as the improvements proposed through this study, can be incorporated into the design of test fixtures for any other orthopaedic implant such as the hip, knee, spine, elbow, and finger.     

Design of an exoskeleton for strengthening the upper limb muscle for overextension injury prevention

Several methods have been proposed for upper limb muscle training using exercise devices or machines to strengthen the muscle groups. However, most exercises control the direction of resistance to isolate specific muscle groups that need to be trained. A compact and cost-effective upper limb exoskeleton design with a 3-DOF shoulder joint and a 1-DOF elbow joint allows a patient or a healthy individual to move the limb in different planes and increases resistance through adjustments of the spring length to train more muscle groups. The exoskeleton springs were designed to equalize the joint torques for the shoulder and elbow joints with the joint torques obtained from free-weight exercises. Experimental data of the joint torques for two healthy subjects for shoulder abduction–adduction, flexion–extension, and elbow flexion–extension exercises with the exoskeleton were compared to measurements obtained from the upper limb dumbbell lateral raise, the dumbbell frontal raise, and the dumbbell curl exercises. The results of our preliminary evaluation showed that this design had an equivalent effect on the joint torques of shoulder and elbow to the free-weight exercises without the risk of overextension injury. Ultimately, this study provided a design and prototype for an upper limb exoskeleton.     

The relationship between surface topography and contact in the elbow joint: development of a two-dimensional geometrical model in the coronal plane

One of the first stages in developing an accurate biomechanical representation of the elbow joint is to model realistically the geometry of the joint. In particular, given the complex anatomy of the articular surfaces, the relationship between surface topography and joint contact must be fully understood in order to model the contact conditions. As the joint articulates, the location and size of the contacts between the mating surfaces change, altering the distribution and magnitude of load transmission. In this paper, a geometric model of the anatomical elbow joint in the coronal plane is described. The contours of the articulating surfaces are represented algebraically by a series of connecting lines and circular arcs. It is shown that the location and size of the contact between the surfaces change significantly due to small changes in the topography of one or more of the mating surfaces. The surface topography-joint contact relationship is modelled for a number of different clinical conditions for the joint. The model is relevant to clinical studies of joint degeneration and to the design of prosthetic components for the elbow joint.     

基于肘体结构的载荷标定试验研究

根据坦克车辆平衡肘体的空间力受载分析，直接采用其结构部件作为测量传感器，通过应变片布置、桥路设计和载荷标定，建立实测载荷的输入与输出关系方程，以此来获得坦克车辆行走部件在实际工作中的随机载荷-时间历程，为其肘体结构可靠性设计和全尺寸结构模拟试验提供科学依据。     

考虑载荷模拟作用的高压弯头冲蚀数值仿真

在水力压裂过程中,地面高压管汇在管内复杂固液两相流冲击和管体恶劣载荷的耦合作用下,弯头、三通及接头等薄弱部件长期遭受严重的冲蚀磨损,极易导致管件发生断裂破坏,对现场人员及设备构成严重威胁。开展载荷作用下的高压管汇典型材料冲蚀磨损试验,根据试验结果,基于E/CRC冲蚀模型构建一种考虑应力状态影响的新型冲蚀数学模型,所构建的新模型与冲蚀试验数据之间的准确度可达95%以上。采用计算流体力学离散相模型（CFD-DPM）,开展高压管汇件冲蚀性能的三维数值模拟,考察高压弯头在不同压裂工况下的冲蚀磨损程度及空间分布情况。结果表明：在固液两相流冲击下,主要冲蚀区位于靠近弯头出口处的弯头外侧,且管件的最大冲蚀率也位于该处;在弯头内侧二次流涡流的影响下,部分颗粒在流经弯头后会在下游直管内侧积聚,从而在这个区域造成次要冲蚀区;随着流动颗粒斯托克斯系数增加,主要冲蚀区面积增大,次要冲蚀区面积减小;此外,在嵌入新型冲蚀数学模型后,可观察到随着操作压力增大,高压管汇弯头部位的冲蚀磨损率明显增加。     

基于SolidWorks的弯管焊接工装设计

弯管是水泥泵车上的易损易耗零件。弯管两端的法兰尺寸和空间位置尺寸准确度均要求较高。弯管的空间形状复杂,壁厚较薄,铸造难度较大。弯管在新产品试制时常根据铸造工艺需要分成几段铸造。各段弯管加工后,再采用焊接组合成一个弯管零件。利用SolidWorks三维建模软件制作弯管的焊接工装,有效地保证了弯管法兰的空间位置尺寸要求,保证了产品质量,提高了生产效率。此焊接工装经过设计和改进后完全满足了弯管组合焊接需要,完成的弯管零件完全符合泵车装配需要。     

基于图像处理技术的弯管数据提取方法

针对管道计算机辅助设计图纸中坐标点信息提取烦琐的问题,基于图像处理技术,采用VS 2010平台开发了弯管数据提取程序。基于图像处理技术的弯管数据提取方法可以实现设计图纸中坐标点信息的快速提取,为计算机辅助设计图纸的信息处理提供了新的方法。     

Design and experimental study of a passive power-source-free stiffness-self-adjustable mechanism

Passive variable stiffness joints have unique advantages over active variable stiffness joints and are currently eliciting increased attention. Existing passive variable stiffness joints rely mainly on sensors and special control algorithms, resulting in a bandwidth-limited response speed of the joint. We propose a new passive power-source-free stiffness-self-adjustable mechanism that can be used as the elbow joint of a robot arm. The new mechanism does not require special stiffness regulating motors or sensors and can realize large-range self-adaptive adjustment of stiffness in a purely mechanical manner. The variable stiffness mechanism can automatically adjust joint stiffness in accordance with the magnitude of the payload, and this adjustment is a successful imitation of the stiffness adjustment characteristics of the human elbow. The response speed is high because sensors and control algorithms are not needed. The variable stiffness principle is explained, and the design of the variable stiffness mechanism is analyzed. A prototype is fabricated, and the associated hardware is set up to validate the analytical stiffness model and design experimentally.