Comparison of engineering failures and seismic responses of 500 kV transformer-bushing systems in the 2022 Luding earthquake

Cemented and mechanically clamped types of end fittings(fitting-C and fitting-M)are commonly used in transformer bushings.During the Luding Ms 6.8 earthquake that occurred in China on September 5,2022,all transformer bushings with the two types of end fittings in a 500 kV substation were damaged.Post-earthquake field investigations were conducted,and the failures of the two types of bushings were compared.Two elementary simulation models of the transformer-bushing systems were developed to simulate the engineering failures,and further compute their seismic responses for comparison.The results indicate that the hitch lugs of the connection flange are structurally harmful to seismic resistance.Fitting-M can decrease the bending stiffness of the bushing due to the flexible sealing rubber gasket.Since it provides a more flexible connection that dissipates energy,the peak accelerations and relative displacements at the top of the bushing are significantly lower than those of the bushing with fitting-C.Compared with fitting-C,fitting-M transfers the high-stress areas from the connection flange to the root of the porcelain,so the latter becomes the most vulnerable component.Fitting-M increases the failure risk of the low-strength porcelain,indicating the unsuitability of applying it in high-intensity fortification regions.

Fate of rubber bush (Calotropis procera (Aiton) W. T. Aiton) in adversary environment modulated by microstructural and functional attributes

Calotropis procera(Aiton)W.T.Aiton,belonging to the family Apocynaceae,is C3 evergreen plant species in arid and semi-arid areas of the Punjab Province,Pakistan.It grows in a variety of habitats like salt affected and waterlogged area,desert/semi-desert,roadside,wasteland,graveyard,forest,crop field,coastline,and river/canal bank.A total of 12 populations growing in different ecological regions were sampled to evaluate their growth,physio-biochemical,and anatomical responses to specific environmental condition.Population adapted to desert/semi-desert showed vigorous growth(plant height,shoot length,and number of leaves),enhanced photosynthetic level(chlorophyll a,chlorophyll b,carotenoids,and total chlorophyll),and apparent anatomical modifications such as increased stem radius,cuticle thickness,storage parenchyma tissues(cortex and pith),and vascular bundles in stems,while the maximum of midrib and lamina thickness,epidermal cells,cuticle thickness,cortical proportion,abaxial stomatal density,and its area in leaves.There was high plasticity in structural and functional features of these populations,which enable them to survive and tolerate under such hot and dry desert environment.Population of saline areas exhibited very critical modifications to sustain under salt prone environment.At physiological level,it possesses the maximum amount of organic osmolytes(glycine betaine and proline)and antioxidants(superoxide dismutase(SOD),catalase(CAT),and peroxidase(POD)),while at anatomical level,it showed intensive sclerification,large phloem region(inner and outer),pith parenchyma cells,and metaxylem vessels in stems and leaves.The population of dry mountains showed very distinctive features,such as increased shoot ionic contents(K+and Ca2+),collenchyma and sclerenchyma thickness in stems,trichomes size,and numerous small stomata on abaxial surface of leaves.It is concluded that no definite or precise single character can be taken as a yardstick for adjudging the biomass production in this rubber bush weed population.

Simulation analysis of wear characteristics of connecting rod bearing bush based on improved mixed lubrication model

The failure rate of crankpin bearing bush of diesel engine under complex working conditions such as high temperature,dynamic load and variable speed is high.After serious wear,it is easy to deteriorate the stress state of connecting rod body and connecting rod bolt,resulting in serious accidents such as connecting rod fracture and body damage.Based on the mixed lubrication characteristics of connecting rod big endbearing shell of diesel engine under high explosion pressure impact load,an improved mixed lubrication mechanism model is established,which considers the influence of viscoelastic micro deformation of bearing bush material,integrates the full film lubrication model and dry friction model,couples dynamic equation of connecting rod.Then the actual lubrication state of big end bearing shell is simulated numerically.Further,the correctness of the theoretical research results is verified by fault simulation experiments.The results show that the high-frequency impact signal with fixed angle domain characteristics will be generated after the serious wear of bearing bush and the deterioration of lubrication state.The fault feature capture and alarm can be realized through the condition monitoring system,which can be applied to the fault monitoring of connecting rod bearing bush of diesel engine in the future.

ADAMS软件中绳索类物体的一种建模方法

针对ADAMS软件中绳索类大变形柔性物体直接建模困难的问题 ,提出并分析了Bushing连接模型的建模方法 。

激光陀螺捷联惯导系统IMU结构模态分析

随着机抖激光陀螺捷联惯导系统以其诸多优点在军用与民用导航领域得到广泛的应用,对其体积和重量的要求变得越来越严格。机抖激光捷联惯导系统IMU小型化设计的关键在于减振系统的设计,而减振器仿真模型的建立是该减振系统模态仿真分析的难点。针对这一问题,提出一种通过ANSYS中的"Bushing连接"来模拟减振器的方法,并利用模态实验结果修正其参数,最终建立了一个准确的减振器模型,实现了对捷联惯导IMU振动模态的精确仿真与分析,为其IMU结构的进一步小型化设计奠定了基础。

海底天然气渗漏系统水合物成藏动力学及其资源评价方法

根据海底天然气渗漏系统沉淀水合物的动力学模型,计算了海底渗漏系统中渗漏天然气沉淀为水合物的比例。如果BushHill渗漏系统海底水合物或喷溢天然气的化学组成是渗漏系统气源天然气通过沉淀水合物转变而成,则需要约3. 3% ~21. 7% (平均12. 9% )的渗漏天然气在海底沉淀为水合物。结合渗漏系统的活动时间(1万年)和天然气流量(800t/a),沉淀在墨西哥湾GC185区BushHill渗漏系统中的水合物天然气资源为0. 37×109 ~2. 43×109 m3,平均为1. 45×109 m3,与体积和含量评价方法获得的结果基本一致。

红胁蓝尾鸲(Tarsiger cyanurus)在中国东北部帽儿山地区的迁徙中途停歇生态(英文)

中国迁徙鸣禽类的保护面对着与世界其他地区如欧洲和北美洲鸟类保护相似的挑战。迁徙鸣禽类具有复杂生活周期和很大的空间关联。迁徙过程中发生的事件对迁徙鸣禽类种群动态具有决定作用。对于鸣禽类迁徙中途停歇期的生态,比如停歇期的长短,能量的积累,生境的利用等,了解还非常有限。在中国东北部的一个鸟类迁徙停歇地对红胁蓝尾鸲(Tarsigercyanurus)的中途停歇生态包括迁徙时间、停歇时间、能量状态和性比进行了研究。2002年秋和2003年春分别捕获了1751只和684只红胁蓝尾鸲。红胁蓝尾鸲的体重在秋季迁徙时要比在春季迁徙时重。春季雌性红胁蓝尾鸲停歇时的能量状态指数最低;而秋季的红胁蓝尾鸲比春季的红胁蓝尾鸲停歇时间更长。无论季节和性别,红胁蓝尾鸲的能量状态指数和第1次捕获的时间早晚成正相关,间接证明红胁蓝尾鸲在停歇期间能够比较快地积累能量。秋季雄性红胁蓝尾鸲日体重净增率最大。估测秋季停歇期的每日能量净增能维持红胁蓝尾鸲雌性0.6h和雄性3.1h的飞行。红胁蓝尾鸲的中途停歇生态与北美和欧洲一些迁徙鸣禽类很相似。比如,春季迁徙过境的时间和脂肪积累的变化与自然选择对雄性的要求:当食物和气候适宜时尽快到达繁殖地的假设是一致的。对迁徙中途的停歇生态研究有利于更好地了解鸟类的迁徙行为和更有效地保护迁徙鸣禽类。

Variable-based Ramberg-Osgood constitutive model of power spinning bushing

The influences of power spinning process parameters on the mechanical properties of spinning parts were analyzed with an SXD100/3-CNC numerical control power spinning machine.The unidirectional tensile tests were carried out.Based on the experimental data,a ternary quadratic regression equation was established by orthogonal experiment.The Ramberg-Osgood constitutive model of tin-bronze connecting rod bushing was obtained.Referred to the constitutive relation of macroscopic incremental,the incremental elastoplastic constitutive relation of spinning parts was deduced based on the Mises yield criterion and kinematic hardening model.The results can be applied to the elastoplastic analysis in finite element numerical simulation.

着陆器软着陆机构的动力学分析

以某型号着陆器软着陆机构为研究对象,采用MSC.Patran/Nastran对软着陆机构进行模态分析,得到结构模态的主要影响因素,主要包括机构尺寸和装配连接方式.主要分析了软着陆机构中主支柱、辅助支柱活塞杆和活塞筒壁厚、以及活塞筒端盖厚度对模态频率的影响,并对主支柱、辅助支柱活塞杆和活塞筒装配连接方式进行研究,接着提出一种基于Bush单元的装配连接方式,有效地解决了传统方法中用MPC(Multiple Point Constraint)刚性连接来模拟装配连接的不足,使仿真结果更加准确.最后对收拢状态下的模型进行了频率响应分析,结果发现在给定的频率范围内结构不会发生共振,进一步说明结构设计的合理性.

Bush型函数的分形维数及其奇异性

本文给出了一类无处可微的连续函数──Ｂｕｓｈ型函数的Ｂｏｘ维数的精确值及其Ｈａｕｓｄｏｒｆｆ维数的下界估计值，同时讨论了Ｂｕｓｈ型函数的奇异性特征．

一种新的Bush型分形曲面及其维数

在 Bush型分形曲线的基础上 ,首先构造了一种分形曲面 ,然后研究这种曲面的分形维数及光滑性。得到了曲面的 Box维数 ,Packing维数的计算公式以及 Hausdorff维数的下界估计式。

基于虚拟样机ADAMS的钢丝绳建模及仿真

在ADAMS中没有针对钢丝绳这一类大变形物体直接建模的工具。重点研究了基于ADAMS创建钢丝绳模型的理论,并分析了用Bushing轴套力和Contact接触力建立模型的方法,为在ADAMS软件中创建钢丝绳模型及仿真分析提供了理论依据。

高层建筑消防飞行机器人结构稳定性

介绍高层建筑消防飞行机器人结构设计,主要包括六翼飞行器、消防装置、辅助设备。介绍机器人的结构组成及各部分的功能特性。对机器人进行受力分析,研究其自身结构的稳定性。分析机器人受外力作用时的平衡性、抗侧风性能,分析牵引绳、转速、涵道风扇对其平衡性的影响。在ADAMS环境下借助bushing模型对牵引绳的牵引性能进行仿真分析。

用Bush型函数构造分形纹理图

给出一类以Bush型函数构造分形纹理图的方法。用hx方法构造的纹理图可以事先确定其精确的Box－counting维数和Packing维数等分形量，因而可广泛应用于图像分析和图像处理中。

Bush型函数图像的K-维数

研究一类基于实数的Cantor级数表示的分形函数———Bush型函数图像的K-维数.得到了这类函数图像的K-维数的上、下界估计式.指出在基于实数的b进制表示的情形下,这类函数图像的K-维数等于其box维数与pack ing维数.

空间机械臂锁紧机构等效线性化分析及验证

空间机械臂的锁紧机构刚度特性具有非线性特征,在开展整臂动力学分析时需要对其进行等效线性化处理,故本文提出了一种基于六维刚度等效的线性化方法并进行了分析验证。建立了锁紧机构单机在预紧状态下的非线性模型,通过非线性计算获取了锁紧机构各向刚度数值,并将其提供给用于模拟锁紧释放机构的BUSH单元。对机械臂整体模型进行了模态分析以及频率响应分析。结果表明:整臂前三阶固有频率为89 Hz、92 Hz和96 Hz,和试验结果最大相差为3%;各组件加速度响应分析结果与试验结果吻合较好,最大相差为8%,证明了提出的线性化方法的有效性。该方法考虑了各向刚度之间耦合关系,并且不必逐一处理锁紧机构接触面,有较强的工程实用价值。

疲劳寿命下连接件的优化设计

连接件是飞机结构中常见的承载结构,但也是常见的疲劳源,连接件上紧固件钉传载荷和孔边旁路载荷直接影响疲劳寿命,采用bush元、beam元和rbar模拟紧固件和板的连接关系,建立了连接件细节有限元模型。为降低端部孔的应力集中,使连接板的厚度呈台阶形状,计算紧固件载荷的分布,然后通过应力严重系数法,确定各个连接件结构的严重孔,最后对各个严重孔的疲劳寿命进行了对比,计算结果表明与理论相符,对结构的优化设计具有参考价值。

刚柔耦合的涡旋压缩机转子系统的动力学分析

以涡旋压缩机转子系统为研究对象,采用Bushing连接模拟轴承,运用Ansys Workbench软件建立了考虑轴承刚度、小轴和动涡旋盘柔性的涡旋压缩机转子系统的刚柔耦合模型,进行了刚柔耦合动力学分析,得到了实际工况和理想工况时运动副反力,以及实际工况时小轴和动涡旋盘的应力、应变情况。仿真结果表明:实际工况时滚针轴承不承担动涡旋盘的倾覆力矩,倾覆力矩由3对7001轴承来承担,并造成轴向气体力分配不均匀,使2号7001轴承受力过大;小轴、动涡旋盘的强度和刚度符合设计要求。研究结果为涡旋压缩机结构设计和优化提供了理论指导。

Effect of Heat Treatment on Microstructure and Property of Al-Sn-Pb Bearing Material

AlSn8Pb2Si2.5Cu0.8Cr0.2 is a bush material with high hardness, and the main elements tin and plumbum mainly exist along the grain boundary, resulting in bad plasticity and confectioning. It is found that the continuous tin and lead distributing along grain boundary are broken by cold-rolling, and their shape is spheroidized and uniform through annealing at constant temperature. The continuous precipitated phase composed of tin and lead doesn＇t exist along grain boundary. The properties of bush material are greatly increased.

Taxonomic Revision of Raorchestes menglaensis(Kou,1990)(Amphibia:Anura),with Descriptions of Two New Species from Yunnan,China

Raorchestes is a group of Bush frogs mainly distributed in South and Southeast Asia that are poorly recognized by morphological criteria.We recognize the true R.menglaensis(Kou) based on 10 specimens newly collected from the type locality.An expanded description is also provided,and we delist the recently reported record,R.parvulus(Boulenger) from China.Combing with morphological and molecular data,two new species are respectively described from Menghai and Lvchun,Yunnan,China.Raorchestes hillisi sp.nov.is distinguished from all other congeners by the following combination of morphological characters:(1) small body sized(males 15.9-17.7 mm,n=7;female 17.5 mm,n=1);(2) head longer than wide;(3) snout longer than eye diameter;(4) the tip of upper jaws slightly notched;(5) internasal space slightly less than interorbital space;(6) tympanum distinct;(7)fingers lacking lateral dermal fringe;(8) outside of toe Ⅰ and both sides of toe Ⅱ lacking lateral dermal fringe,other toes having weak lateral dermal fringes;(9) rudimentary web on toes;(10) lacking a series of tubercles along the outer sides of forearm and foot;(11) discs of fingers and toes not orange.Raorchestes huanglianshan sp.nov.is distinguished from all other congeners by the following combination of morphological characters:(1) small body size(males 17.0-19.6 mm,n=12;female 21.5 mm,n=1);(2) head slightly wider than long or equal;(3) snout longer than eye diameter;(4)the tip of upper jaws slightly notched;(5) internasal space distinctly less than interorbital space(6) tympanum distinct;(7) fingers lacking lateral dermal fringe;(8) toes lacking lateral dermal fringe;(9) rudimentary web on toes;(10)lacking a series of tubercles along the outer sides of forearm and foot;(11) discs of all fingers and toes orange or parts of them orange in life.