摘要：A disc rubber vibration isolator with quasi-zero stiffness (QZS)was designed,and the char-acteristics of vibration isolation were studied.The QZS isolator was devised by assembling a reinforced disc rubber with negative stiffness in parallel with a vertical rubber cylinder with positive stiffness.By u-sing Finite Element Analysis (FEA),the geometrical parameters of the reinforced disc rubber and the ver-tical rubber cylinder were achieved to ensure that the isolator's stiffness is close to zero at the static equilib-rium position.And then,the characteristics of restoring force were analyzed,and the expression of resto-ring force was given as a polynomial only having cubic item by fitting the FEA simulations data.Moreo-ver,the equation of motion of the vibration isolation system was obtained,and the isolation performance was evaluated theoretically based on Harmonic Balanced method,which was compared with that by using dynamic FEA.The results have shown that the QZS isolator significantly outperforms the corresponding linear one.%设计了具有准零刚度(QZS)特性的碟形橡胶隔振器，并分析了其隔振特性。隔振器由负刚度元件碟形橡胶(内含钢材料的筋)与正刚度元件竖直橡胶柱并联组装而成。基于 Abaqus 有限元仿真分析，给出了隔振器在静平衡位置处出现零刚度时，碟形橡胶元件和竖直橡胶元件分别需要满足的构型和尺寸参数条件，得到了隔振器的回复力曲线，并用仅含三次的多项式进行了拟合。进一步，建立隔振系统动力学方程，基于谐波平衡法分析了系统的隔振特性，并与 Abaqus 动力学仿真分析进行对比，结果表明，碟形橡胶准零系统隔振性能明显优于相应的线性系统。
摘要：AC supply and DC supply coexist in electrified railway in some countries,such as South Af-rica.When a locomotive runs to a railway section powered by DC,its transformer is usually used as a filter reactor.In this paper,the electromagnetic characteristics of a locomotive transformer in DC system were studied with a geometry of"C-core" core-type and four high voltage windings and four low voltage wind-ings symmetrically arranged on two core limbs respectively.When a locomotive is powered by DC,the four high voltage windings of a transformer are connected in parallel and in open circuit,and the two low voltage windings on a limb are connected in series and used as the filter reactor.There are two DC powered circuits in a locotomotive and one of them can work alone or the two work together.In this paper,themagnetic field of the transformer was analyzed and the inductances were calculated,in which different con-nections of the four low voltage windings were considered.Moreover the characteristics of inductances with changes of the currents in the windings were studied,and the inductance computation was proved with tests for that in which a DC circuit works alone.Then,a proper connection of the low voltage wind-ings in DC system was proposed according to the above analysis.Finally,some investigation was done to increase the inductance when a DC circuit works alone and an improved design was presented.%跨线运行的电气机车，由直流供电时其变压器用作滤波电抗器。本文针对一台心式结构且具有4个高压和4个低压(牵引)绕组的机车变压器在直流供电时的有关电磁特性进行了研究。此时，高压绕组并联开路，低压绕组两两串联分别接入两个直流回路中用于滤波，两个直流回路或同时工作或单独工作。按同一铁心柱上两个绕组串联连接，则4个低压绕组有4种接法。文章在用 ANSYS 软件对磁场进行深入分析的基础上，计算了绕组间的电感矩阵及相应连接时的电感。同时，深入研究了4个低压绕组两两串联后或同时工作或单独工作时电感值随负载电流变化的特性，推荐了直流制式下变压器用作滤波电抗器时其低压绕组一种较合适的连接方式，且这种连接方式的电感计算值得到了试验验证。文章最后还针对所推荐的连接方式，在单回路工作时较双回路工作时所呈现的电感值差异，提出了一种增设第三绕组的补偿方案，并就有关问题进行了分析。
摘要：Large data RDMA (Remote Data Memory Access)transport is the most commonly used par-allel communication mode for parallel computers,which has great impact on the whole system perform-ance.As the system size increases,the fault-tolerate architecture design faces new challenges.The inter-connection network usually uses the adaptive routing mode and becomes more unreliable.This paper pro-posed a fast RDMA offload method for unreliable interconnection networks,which can be efficiently imple-mented on the NIC hardware and provides reliable RDMA communication for upper driver and programs. Compared with the traditional approaches,the hardware overhead is greatly reduced.Another benefit is that it can partially retransmit the fault data,which greatly reduces the whole RDMA delay.Simulation results show that the RDMA delay is greatly reduced,compared with the traditional methods.%大数据量的远程内存访问(RDMA)传输是并行计算机中最基本的通信模式之一，对系统整体性能的影响很大。随着并行计算机系统的规模扩大，系统的容错性设计面临着很大的挑战，互连网络具有链路不可靠、自适应路由等特点，如何面向不可靠网络实现可靠的端到端 RDMA 传输是并行系统体系结构设计的一大难题。提出一种面向不可靠网络下的快速 RDMA 传输方法，方法能够在节点控制器芯片上高效实现，对上层驱动软件和应用提供可靠的端到端 RDMA 传输服务。与传统的建立连接的方法相比，方法的硬件设计复杂度大大降低；方法另一优点是实现了按需重传，避免了传统方法中一次 RDMA 传输出现错误时，需要重传整个 RDMA 数据的开销，在相同的错误概率下，新方法的传输效率得到了很大的提升。
摘要：为了快速挖掘大规模空间数据的聚集特性，在 cluster_dp 密度聚类算法基础上，提出了一种基于弹性分布数据集的并行密度聚类方法 PClusterdp.首先，设计一种能平衡工作负载弹性分布数据集分区方法，根据数据在空间的分布情况，自动划分网格并分配数据，使得网格内数据量相对均衡，达到平衡运算节点负载的目的；接着，提出一种适用于并行计算的局部密度定义，并改进聚类中心的计算方式，解决了原始算法需要通过绘制决策图判断聚类中心对象的缺陷；最后，通过网格内及网格间聚簇合并等优化策略，实现了大规模空间数据的快速聚类处理.实验结果表明，借助 Spark 数据处理平台编程实现算法，本方法可以有效实现大规模空间数据的快速聚类，与传统的密度聚类方法相比具有较高的精确度与更好的系统处理性能.%This paper proposed a density based parallel clustering algorithm to mine the feature of large scale spatial data.The proposed PClusterdp algorithm is based on the cluster-dp algorithm.First,we in-troduced a data object count based RDD partition algorithm for balancing the working load of each compute node in computing cluster.Second,we redefined the local density for each data point to suit the parallel computing.Meanwhile,in order to get rid of original algorithm's decision graph,we proposed a method to automatically determine the center point for each cluster.Finally,we discussed the cluster merge strata-gem to combine the partially clustered data together to generate the final clustering result.We implemen-ted our Resilient Distributed Dataset (RDD)based algorithm on Spark.The experiment result shows that the proposed algorithm can cluster large scale spatial data effectively,and meanwhile,the method has bet-ter performance than the traditional density clustering methods and can achieve the rapid clustering of mas-sive spatial data.
摘要：Aiming at the die wear problem of ultra high strength steel stamping forming,an effective and fast method was proposed for predicting die wear and working life.The method adopted Archard wear theory in order to obtain mould wear data after stamping forming.Die wear was mainly concentrated in the die round corners.The factors affecting die wear were analyzed systematically.These factors include die hardness,stamping speed and die material.The results showed that the die wear decreased effectively when the die hardness reached 60 ~ 65 HRC.The die wear was positively correlated with the stamping speed.Wear cumulation method was used to predict the service life of die,which had stamped 7500 times. the difference between die wear calculated by simulation and test data was only 1.47%,which showed that the method was feasible.The method has an important practical value in determining reasonable stamping process and designing die structure.%针对超高强钢板冲压模具的磨损问题，提出一种有效而快捷的预测模具磨损量和使用寿命的方法.该方法采用 Archard 磨损理论，得到冲压成型结束后模具的磨损区域主要集中在模具圆角处.系统地研究了模具硬度、冲压速度和模具材料对模具磨损程度的影响.结果表明：模具硬度达到60~65 HRC 时能有效减小磨损量；模具磨损量与冲压速度成正相关关系.采用磨损累积法预测模具修模前的使用寿命，模拟得到的冲压7500次的模具磨损量与试验数据仅相差1.47%，表明该方法是正确可行的.这对于确定合理的冲压工艺方案和模具结构设计具有重要的实用价值.
摘要：分布式电源接入配电网后，孤岛运行可以作为一种新的故障恢复方式，保障重要负荷的供电。本文提出了一种基于距离权重搜索孤岛的启发式孤岛划分方法，以恢复的重要负荷最多为主要目标，充分考虑孤岛安全运行的约束条件，计及不可控负荷的影响，引入距离权重来表征负荷与当前孤岛的距离远近，决定负荷并入孤岛的先后顺序。在先形成仅含分布式电源和相连支路的初始孤岛后，按负荷重要程度，依次并入距离当前孤岛最近的负荷，最后对划分好的孤岛进行安全校验和优化。仿真结果表明了该方法能在配电网发生故障后，动态划分合理的孤岛范围。%With plenty of distributed generators connected to distribution system,island operation can be used as a new fault recovery approach to ensure the power supply of critical loads.A heuristic islanding algorithm based on dis-tance-weight was proposed,taking the maximum recovered critical load as the main target,considering the pact of va-rious operation constraints and uncontrolled loads of the distribution networks,introducing distance-weight which re-presents the distance between the objective load and the island to find out which load is the nearest to the current is-land and should be recovered first.The initial island is composed of all the DGs and some branches between them,and then enlarged by merging the nearest load among all the considered loads.Finally,it will get security assessment and be regulated.Simulation results have demonstrated that the proposed algorithm can generate a reasonable islanding scheme after a fault occurs.
摘要：正交压控振荡器是高速链路中的一个关键部件.片上集成高质量品质的电感电容等无源器件是影响压控振荡器性能的关键因素.为了兼容传统的数字工艺,采用超深亚微米的数字 CMOS 工艺进行片上电感电容的集成,并基于此无源器件实现了基于电容耦合的正交压控振荡器,实现中心频率16.12 GHz,频率调节范围为10%,1M 频偏处的相位噪声为-112 dBc,相位误差小于0.39°.%Quadrature VCO is one of the key components in high speed data link.High Q on-chip in-ductance and capacitance integration is a key fact,which highly affects the performance of Voltage Con-trolled Oscillator.In order to fully compact the traditional digital CMOS process,we have designed on-chip inductance and capacitance with ultra-deep submicron digital CMOS process,based on which a capaci-tive coupling quadrature VCO is implemented.According to the simulation,the center frequency of QVCO is 1 6.12GHz,with 10% frequency tuning range,-1 12dBc@ 1MHz phase noise and 0.39°phase error.
摘要：The influence of surface roughness in the difficult-to-polished blade regions,such as blade tip,blade fillet and hub,on the aerodynamic performance of the compressor rotor was investigated in order to define the required roughness in these regions for blade polishing.How the roughness in the above-men-tioned regions of the rotor affects pressure loss coefficient and outlet total pressure on conditions of 98%choke mass flow in different design speeds was analyzed with the numerical aerodynamic calculation of ro-tor 37 based on computational fluid dynamics (CFD)tools.The results show that the rotor losses increase with the roughness in the difficult-to-vlished regions of the blade,and the outlet total pressure increases with the roughness of blade tip but decreases with the roughness of blade fillet and hub.The surface roughness value 15 μm is considered as a turning point,because it affects the aerodynamic performance more significantly when it is greater than 15 μm.The aerodynamic performance is most affected by the hub roughness.The hub roughness reduces the rotor losses at 60% of the design speed,but increases the rotorlosses at 80%,100% of the design speed.%研究压气机转子中叶片叶顶、叶根倒圆、下端壁这类难以自动抛光区域的表面粗糙度对转子气动性能的影响规律，旨在为叶片抛光加工表面粗糙度目标的制定提供指导。基于计算流体动力学(CFD)对跨音速转子 rotor37进行气动计算，分析了98%阻塞流量工况不同转速下各部位表面粗糙度对转子的损失系数和出口总压的影响规律。结果表明，在设计转速下，叶片各部位的表面粗糙度增加均使转子损失增加，叶顶的表面粗糙度使出口总压升高，而叶根倒圆和下端壁表面粗糙度使出口总压降低；表面粗糙度15μm 是一个转折点，大于15μm 时表面粗糙度对气动性能的影响程度开始变大；下端壁表面粗糙度对性能的影响最大，在60%设计转速下，下端壁表面粗糙度使损失降低，但是在80%和100%设计转速下，则使损失增加。
摘要：针对目前液压挖掘机能量利用率低、油耗高的问题，分析挖掘机在典型作业工况下的能量损耗，确定混合动力系统进行节能研究的重要方向。根据混合动力挖掘机的特点，提出基于超级电容与电机的并联式油电混合动力系统方案，以山河智能公司20吨级液压挖掘机为平台建立系统仿真模型，对系统动力耦合特性、控制策略及超级电容 SOC 等因素给混合动力挖掘机节能效果带来的影响进行理论计算和仿真分析，并对系统关键参数进行了优化匹配。搭建液压挖掘机混合动力系统试验平台，对系统的节能效果进行试验验证。研究结果表明，采用油电并联混合动力系统，并选择合适的动力耦合参数、瞬时优化控制策略及超级电容 SOC 补偿参数有利于提高液压挖掘机的节能指标，节能效率可改善20%以上。%Based on low utilization rate of energy and high fuel consumption,the energy losses in the hydraulic excavator during typical working condition were analyzed,and the major directions of the energy saving research for the hybrid power system were derived.A parallel hydraulic & electric configuration for hybrid excavator was proposed based on capacitor and motor.For the hybrid power system based on SUN-WARD 20T hybrid excavator,the paper established simulation model,and the effect of the power coupling characteristics,the control strategy,the capacitor’s State Of Charge on the hybrid excavator were studied by contrast calculation and simulation.And the key parameters were optimized and matched.At last the energy saving effect was studied by building test platform of hybrid system,and found that adopting the parallel hydraulic & electric system,selecting the appropriate parameters in power coupling,instantaneous optimization of control strategy,compensating parameter of capacitor SOC are helpful to improve the ener-gy saving effect of hybrid excavator,and the energy saving efficiency can reach above 20%.
摘要：A finite element model of a water-lubricated bearing at low speeds,and heavy loads was es-tablished.The Explicit module of Abaqus was used to analyze the influence regularity of transient per-formance on the water-lubricated bearing with different friction factors,loadings and revolving speeds,and the vibrational frequency and acceleration RMS of the bearing were obtained.Finally,the results were val-idated with experiments.The results have indicated that the stability of the system reduces and more vi-brational noises rise with the increase in friction coefficient,the vibration response of the bearing system increases with the increase in loading within a certain range,but there is less impact from revolving speeds on the vibration frequency of the bearing.However,the accelerated speed of the system is getting higher with the increase of revolving speed,and the simulation analysis results are consistent with the experiment results,and it provides a theoretical basis for the study of the vibrational noise mechanism of water-lubri-cated bearings.%建立低速重载条件下水润滑轴承有限元模型，应用 Abaqus /Explicit 模块分析不同摩擦系数、载荷、转速对水润滑轴承瞬态特性的影响规律，确定轴承的振动频率和振动加速度有效值，并进行实验验证。结果表明：摩擦系数越大，系统的振动幅值越高，振动噪声的分布越大，系统的稳定性越低，在一定范围内，随着载荷的增加，轴承系统的振动增大；转速对水润滑轴承振动频率的影响较小，但系统的振动加速度随着速度的增大而增大。有限元分析与实验结果基本吻合，为研究水润滑轴承的振动噪声机理提供理论依据。
摘要：The arbiter architecture of the ring bus was studied,and a novel extensible pipelined design was proposed,which can allocate the communication buffers and links simultaneously.Three characteris-tics have been found in the proposed design.Firstly,the arbiter is fair for each node,only with a 5%difference of the hit number.The communicated nodes were found in the simulation when the arbiter in an interconnect system was modeled with 14 nodes.Secondly,compared with the crossbar design,the worst time delay of our synthesis RTL design with Chartered 65 nm Technology was reduced by 36.8%.Fur-thermore,as the number of the nodes has less effect on the key circuit,the arbiter has certain scalability.%对环形网络的仲裁器结构进行研究，提出了一种可扩展流水仲裁器结构，能够同时完成通信缓冲和通信链路的分配.对14个通信节点互连进行了建模模拟，各节点命中数量差值小于5%，该结构仲裁器具有较好的仲裁公平性；然后采用 Chartered 65 nm 工艺对 RTL 设计进行了时序综合实验，关键通路延迟比同等规模的全交叉开关结构降低36.8%；同时该仲裁结构中的仲裁核心逻辑时序受互连规模变化影响较小，具有一定的可扩展性.
摘要：为了解决磨削工件在线粗糙度等级识别速度慢和准确性不高的问题,开发了基于 DSP 的工件表面粗糙度在线检测系统.该系统基于光散射原理,通过工业相机采集光散射图像,运用 DSP 芯片对采集到的图像进行图像预处理以及特征参数的提取；最后利用建立的多分类支持向量机模型,对不同表面粗糙度等级的图像进行分类.实验结果表明,在该硬件平台上整个识别过程耗时约0.5 s,识别率可达96%以上,说明该系统可有效识别工件表面粗糙度等级,有效实现工件表面粗糙度的在线检测.%In order to solve the problems about slow speed and low accuracy on the online roughness recognition of the grinding workpiece,an online measurement system for surface roughness was developed based on DSP.In this system,the surface scattered images based on the light scattering principle were captured by an industrial camera,then these images were preprocessed and their feature parameters were extracted by the DSP chip.Finally,these images with different surface roughness were classified by the multi-class support vector machine model.Experimental results show that it takes about 0.5 s for the en-tire identification process and the recognition rate can be up to 96% or more on this hardware platform,so this designed system can effectively identify the level of the surface roughness and realize the online testing of surface roughness.
摘要：To study the temperature field distribution of engine cylinder head more precisely,based on the Euler multi-phase model,a new two-phase flow model combining the Rohsenow core boiling heat transfer model was established,which can be used for the numerical simulation of subcooled boiling.Ap-plying BDL and Rohsenow transfer models separately,the cylinder head fluid-solid coupling heat transfer system was simulated and analyzed with the CFD technology.The results have shown that the Rohsenow core boiling heat transfer model is more precise than the BDL model in calculating the temperature field of engine cylinder head.The highest temperature of the cylinder head is 1 92.22 ℃,and the maximum of stress is 235 MPa,both of which can meet the strength requirements of cylinder head materials.%为了更精确地研究发动机缸盖温度场的分布,在 Eular 多相流模型的基础上,结合 Rohsenow 核态沸腾传热模型,建立新的可用于内燃机缸盖水腔内过冷沸腾数值模拟的两相流模型.以某汽油机缸盖为研究对象,分别采用 BDL 和 Rohsenow 两种传热模型,利用 CFD 技术对其进行流固耦合传热计算和分析.结果表明,采用 Rohsenow 沸腾传热模型能够比 BDL 沸腾模型更精确地计算缸盖温度场；缸盖的最高温度192.22℃,最大应力156 MPa,均满足缸盖材料的强度条件.