牙种植体三维有限元模型分析

在对牙种植体骨界面进行力学分析的基础上,提出一种牙种植体三维有限元模型。这一模型可用于研究牙种植体骨界面的应力、应变分布,并为牙种植体形态的优化设计提供理论支持。     

基于仿生咀嚼机器人的种植体螺纹结构研究

为了探讨咀嚼受载过程中种植体螺纹形状对骨界面的影响,基于咀嚼仿生平台研究了种植系统中常见的梯形、支撑形和反支撑形三种不同的种植体螺纹在冲击载荷下的力学行为。首先以仿生咀嚼机器人为实验仪器,模拟了口腔的咀嚼过程并实现咀嚼力的采集;之后将咀嚼力作为数值模拟的加载条件分析了不同螺纹种植体的应力分布情况。分析结果显示:在400N的加载下,不同的种植体的应力分布情况大致相同,螺纹部分的应力集中主要发生在自牙冠向下的第一道螺纹处,但是梯形螺纹种植体的集中应力值(242.8MPa)最小,支撑形螺纹最大(278.8MPa);同时就骨组织而言,不同的种植体受载下,皮质骨上的集中应力都明显高于松质骨。     

链轮受力的三维光弹试验研究

用三维光弹实验法对链轮齿的受力进行三维应力分析。确定了链轮齿应力场分布规律及轮齿的最大应力，找出轮齿的危险区域，最后提出了改进措施。     

基于ANSYS Workbench的大型香蕉筛动力学分析

针对目前存在的问题及需求,用Solid Works建立了BVB3661香蕉筛的三维模型,对其部分结构进行了适当的简化,导入Workbench里进行了模态分析,得到其前12阶振型和固有频率,得知工作频率远离固有频率,振动筛不会发生共振。对振动筛进行谐响应分析,得到其在工作频率下的应力响应和位移响应,其数值符合设计要求。考虑振动筛所受的惯性力和重力对筛箱应力的影响,利用Design Assessment模块对几种受力下的应力分布进行了组合求解,得到了接近实际工况下振动筛的应力分布。为筛箱结构的设计优化提供了重要参考。     

端面谐波传动中啮合力分布规律的边界元分析

本文用三维边界元法计算了端面谐波传动中柔轮齿间啮合力分布规律及侧隙,为准确计算端面柔轮齿根应力奠定了基础。通过对四组不同结构参数的柔轮的计算结果分析,提出了一些关于柔轮及波发生器凸轮结构参数选择的建议。     

三维编织复合材料高压储气瓶的屈曲分析与优化设计

通过对三维编织复合材料圆柱壳进行屈曲和应力分析，对三维编织复合材料高压储气瓶的临界载荷、强度和应力分布等进行了数值计算，结果表明，屈曲对三维编织复合材料高压储气瓶使用性能的影响非常显著。基于圆形四步法三维编织工艺及理论分析，提出了三维编织复合材料高压储气瓶的结构优化设计数学模型。算例表明，该优化设计方法效果很好。     

随机振动应力幅值的分布规律

文中用三角级数法对不同谱宽系数的应力响应功率谱进行时域模拟,采用雨流循环计数方法获得应力幅值概率分布,比较了四种应力幅值概率密度函数模型对不同谱宽系数的应力循环雨流幅值分布描述的准确程度,并指定了各种应力幅值概率模型的适用范围。数值模拟结果表明:谱宽系数ε0.5的宽带随机过程Dirlik概率模型比较准确的描述了应力幅值的概率分布;谱宽系数在0.3到0.5之间,给出的四种概率模型均不能较好的描述其应力幅值分布。     

热水器内胆工作状况有限元分析

根据所提供的内胆图纸和实际工作状况，建立三维CAD模型和反映内胆实际工作状况的三维有限元模型。对热水器内胆在实际工作状态下的整体应力、变形分布进行分析，得出了不同材料厚度对热水器主要部件应力和变形的影响，提出了满足设计要求的厚度参考值。     

基于流体动力学的弯管应力有限元分析

由直管弯制而成的弯管几何形状和结构复杂，在流体作用下受力复杂，准确的应力分析是进行强度计算和弯管设计的重要前提。使用ANSYS流体-固体有限元分析软件，建立了管内流体动力学分析和弯管结构应力三维分析模型，利用两种不同物理环境的转换，得出了弯管在流体不均匀压力作用下的应力分布，讨论了流量、弯管加工缺陷对弯管应力的影响。     

基于有限元分析的压力容器应力分布研究

考虑到压力容器的结构对称性,选取1/4模型作为研究对象,采用三维有限元分析方法获得卧式压力容器的应力分布状况。详细描述了容器的应力分布以及支座中各个不同部件的应力分布情况,同时还研究了变化载荷及不同几何参数对应力的影响。推荐在压力容器和鞍式支座设计中2项最优比值,即压力容器端部到支座距离与压力容器长度之间的比值。     

Minimal Realization of Linear Graph Models for Multi-physics Systems

An engineering system may consist of several different types of components,belonging to such physical"domains"as mechanical,electrical,fluid,and thermal.It is t...     

Quantum Cooperative Robotics and Autonomy

The intersection of Quantum Technologies and Robotics Autonomy is explored in the present paper.The two areas are brought together in establishing an interdisci...     

考虑进油孔有限长滑动轴承油膜力的近似解析解

针对具有进油孔的有限长滑动轴承油膜力求解问题,采用变分原理和分离变量法,求得了有限长滑动轴承油膜压力分布的近似解析表达式。将油膜压力分布的近似解析表达式在油膜存在区域上进行积分,即得到了油膜力。将提出的计算有限长滑动轴承油膜力方法与无限长轴承模型、有限元方法的计算结果进行了比较,发现了提出的方法与有限元方法的计算结果很接近。最后,研究了进油孔位置和进油压力对油膜存在区域、油膜力等的影响,研究结果表明进油孔位置和进油压力对油膜存在区域和油膜力有较大的影响。     

三绕组变压器的双绕组等效建模及在Matpower中的应用

针对实际电网存在着大量的三绕组变压器,但国际上一些著名商业软件,如BPA仿真软件、Matpower这一权威潮流计算开源软件,均只提供双绕组变压器模型,限制了其在具有三绕组变压器的电力系统中的应用的问题,潮流计算是自主开发的电力系统各种应用软件的核心模块,因此依托国际权威开源程序进行二次开发,是一种较好的选择。对Matpower要求的数据格式进行了归纳,对变压器的一般的等值电路及带理想变压器的等值电路和带标幺值的等值电路进行了分析研究,提出了三绕组变压器转换为双绕组等效模型的建模方法,使得原先只适应双绕组变压器的潮流计算软件可以适用于三绕组变压器电网的潮流计算;最后以Matpower软件为例进行了案例计算,并用PSASP仿真软件进行对比验证。研究结果证明,所提出的建模方法是有效的。     

On the Relation of Load to Average Gap in the Contact Between Surfaces with Longitudinal Roughness

A computer simulation model for the contact between longitudinally-oriented rough surfaces has been formulated. This model closely duplicates the actual surf ace contact deformation behavior by taking into account the elastic interactions between the asperities. There were no assumptions made about the shapes, or any deformation behavior of the asperities, except for their obeying the laws of elasticity. The plastic deformations on the high asperity peaks were taken into account by setting a ceiling on their contact pressures at the material hardness value. The simulations used real surface profiles which were digitized from unworn circumferentially ground steel surfaces. Each pair of these profiles was mathematically combined to form an equivalent rough profile pressing against an infinitely rigid flat and having the appropriately adjusted elastic modulus. A total of 28 different pairs of profiles were used in the simulations. Each contacting pair was subjected to 30 different load levels and the local contact pressures and deformations were calculated. The contact simulations yielded some important mathematical relationships between parameters, such as the real area of contact, average gap, and average asperity load through statistical curve fitting. Two analytical functions were generated to relate the average load to average gap and the real area of contact to load.     

INTEGRAL EQUATION METHOD＇S APPLICATION IN HOLE-EDGE STRESS OF COMPOSITE MATERIAL PLATE WITH DIFFERENT SHAPED HOLES

The strength of composite plate with different hole-shapes is always one of the most important but complicated issues in the application of the composite material. The holes will lead to mutations and discontinuity to the structure. So the hole-edge stress concentration is always a serious phenomenon. And the phenomenon makes the structure strength decrease very quickly to form dangerous weak points. Most partial damage begins from these weak points. According to the complex variable functions theory, the accurate boundary condition of composite plate with different hole-shapes is founded by conformal mapping method to settle the boundary condition problem of complex hole-shapes. Composite plate with commonly hole-shapes in engineering is studied by several complex variable stress fimction. The boundary integral equations are founded based on exact boundary conditions. Then the exact hole-edge stress analytic solution of composite plate with rectangle holes and wing manholes is resolved. Both of offset axis loadings and its influences on the stress concentration coefficient of the hole-edge are discussed. And comparisons of different loads along various offset axis on the hole-edge stress distribution of orthotropic plate with rectangle hole or wing manhole are made. It can be concluded that hole-edge with continuous variable curvatures might help to decrease the stress concentration coefficient; and smaller angle of outer load and fiber can decrease the stress peak value.     

Fifth International Summer School on Screw-Theory Based Methods in Robotics

正3-11 September,2014University of Bologna,Bologna,Italy www.summerscrews.org summerscrews2014.ing.unibo.it SUMMER 20SCREWS 14In 2014,our screw-theory school comes to the world's oldest university.In early September,Summer Screws'14 will gather six experts in the application of screw theory in robotics and up to 40 participants at the University of Bologna,Bologna,Italy.The school will teach attendees how to apply existing methods and empower them to develop new ones in their own research.The basic theoretical notions will be introduced in a rigorous manner,emphasizing examples,applications,and exercises.Scholarships are available.     

电站锅炉模糊风险评价方法研究与应用

针对电站锅炉风险等级评价问题,将模糊综合评价技术应用到电站锅炉风险等级评价中。开展了电站锅炉失效影响因素及模糊评价因素的重要程度分析,建立了一套科学合理适于在线评价的电站锅炉风险评价体系,提出了模糊综合评价技术与改进的模糊层次分析法相结合的模糊风险评价方法,利用改进的模糊层次分析法计算了指标体系中各层指标权重。对某一台电站锅炉的实际运行工况影响子因素进行了模糊风险评价,采用模糊合成算子进行模糊综合运算得到电了站锅炉运行工况影响子因素的评价向量。研究结果表明:电站锅炉的运行工况影响子因素的风险评价等级为第6级,失效可能性等级为小,该电站锅炉运行工况良好。     

INDUSTRIAL ENGINEERING AND VISUALISATION-A PRODUCT DEVELOPMENT PERSPECTIVE

Taking the actual project of teaching and researching process for example, the relationship between the industrial engineering and product development is discussed. And use the novel visualization technology to support the industrial engineering and product development. How to use the new computer modeling and simulating technologies to support the product development and industrial engineering, is introduced especially. The support includes both domestic products and industrial systems. The visualization and computer technologies take a very important role in some system or multi-direction modeling, those technologies mentioned above can help the industrial engineers study the effect of design on the whole life circle, including the producing steps. So the engineers can avoid making the wrong decision which may cause bad effects on the whole industrial engineering.     

Short-Term Relay Quality Prediction Algorithm Based on Long and Short-Term Memory

The fraction defective of semi-finished products is predicted to optimize the process of relay production lines, by which production quality and productivity ar...