汽车盘式刹车机构的模态与热力耦合分析

汽车盘式刹车机构在刹车片与刹车盘表面接触摩擦制动时导致刹车片发生振动,当刹车片振动频率与材料固有频率接近时,易导致片体结构暗裂崩溃。不同材料的刹车片的固有频率、与刹车盘摩擦作用产生的温度场、热力场各不相同。通过对不同的材料参数下刹车片的模态分析研究,使用Abaqus对刹车机构做显式动力学热力耦合分析;对输出的刹车片固有频率和刹车盘节点温度、位移、热应力等结果值进行对比,数据显示在刹车制动过程中复合材料的刹车片在避免共振、提高制动性能方面均要优于半金属材料。综合分析求解的结果在提高刹车制动机构的安全性与制动效能上有较大参考价值。     

汽车制动性能台架试验方法

近年来大量汽车被运用于市场及人们的日常生活中,为了保证人们出行的安全性,汽车厂商及检测机构在汽车制动性能检测方面格外的重视,随着汽车产量的急速增长,汽车制动性方面的检测量逐年扩大,要在此背景下准确快速地检测出该汽车制动性是否合格,就必须创新路试检测制动性的方法,取其精华,去其糟粕,以台架试验方法代替,快捷地评价出汽车制动性能。     

新型复合材料盘式刹车片的模态研究

刹车片的固有频率对盘式制动器的减振降噪研究有着重要意义.对新型复合材料盘式刹车片和半金属盘式刹车片进行了自由模态和约束模态的对比分析,得到了固有频率等模态参数.从模态分析结果可以看出,在无约束和有约束两种情况下新型复合材料刹车片的固有频率均高于半金属刹车片,半金属刹车片的前四阶约束模态可能与制动噪声有关,而新型复合材料刹车片只有第一阶约束模态可能与制动噪声有关.新型摩擦材料具有高的比模量,材料性能明显优于半金属摩擦材料.     

分布式粮仓温度实时监测系统的设计

为了解决传统的人工测量粮仓温度效率低下的问题,提出了以DS18B20和单片机为核心的分布式温度实时监测系统的软硬件设计方案.该系统内部设计了模糊控制器,能根据用户设定自动采集现场的数据进行显示并判断是否超限报警,测量的数据经过RS485总线传送到上位机中,上位机软件具有数据存储、分析和报表打印等功能.在实际运用中,该装置测量精度高、控制性能良好,满足了针对粮仓温度测量的实际要求.     

汽车制动性能评价指标与检测参数问题分析与探讨

汽车制动性是汽车安全性的主要性能之一，车辆制动性能检测法规、标准和检测技术是进行车辆制动性定期检测的基础。本文介绍了汽车制动性能评价指标，并对汽车制动性能检测相关参数问题进行了探讨和分析。     

汽车制动性概述与制动性检测方法研究

汽车在人们的生活中扮演着越来越重要的角色,随着现代汽车技术的发展和行驶速度的提高,汽车制动性能的好坏程度直接牵扯到安全交通事故,交通事故的发生往往与汽车在制动时的制动距离长、制动时发生甩尾侧滑等因素有关,汽车制动性的重要性也显得越来越明显。本文将探讨汽车制动性的指标、影响因素和汽车制动性的检测方法,这将为汽车检测维修人员掌握汽车制动性的理论知识和维修检测方法提供帮助。     

转鼓制动实验台数据采集系统的设计

在现有转鼓实验台的基础上,应用数据采集卡PCL-818L设计了车辆制动检测实验过程中的实时数据采集系统,并详细介绍了该系统的硬件以及软件的设计过程,最终实现了对车轮制动时的主要参数进行检测,为制动实验提供了一套实用的方法.     

基于逆向工程建模技术和有限元法的汽车盘式制动器NVH特性研究与优化

以某型盘式制动器为研究对象,采用仿真分析与实验相结合的研究方法针对汽车盘式制动器噪声问题进行研究。基于三维扫描技术,通过利用handyscan设备,获得制动器卡钳体点云数据,并在Catia及Solidworks中进行拟合处理建立准确的盘式制动器三维模型。在对盘式制动器NVH特性研究分析过程中,采用具有三层结构设计的刹车片,通过改变刹车片材料中粘弹性成分及刹车片参数的方法进行盘式制动器NVH性能优化。首先针对制动器各子结构的三维模型进行模态分析,获得可能发生制动尖叫的模态频率及振型,并通过F.R.F共振频率测试仪和激光测振仪等实验,验证了有限元模态分析所得结果的正确性,Dyno台架试验结果以用来验证仿真结果预测的准确性与可信度。实验结果证明,优化后刹车片能够提高汽车盘式制动器NVH性能,制动噪声得到降低。     

基于STM32的动平衡振动信号采集系统设计

提出了一种基于STM32的嵌入式系统对振动信号采集的设计方案。阐述了设计此采集系统的必要性,并从硬件方面介绍分析了信号调理模块和通讯模块,在软件方面介绍了应用程序。最后,对采集数据进行了实验分析,检测该设计的准确性和可靠性。     

FZ-10C型反力式滚筒制动试验台远程检测系统的设计

为了加强汽车综合性能检测站的信息化管理,根椐有关要求首先对FZ-10C型欧式粘砂反力式滚筒制动试验台进行了计算机测控方面的升级改造试验。然后从FZ-10C型反力式滚筒制动试验台的制动原理、数据采集以及制动台与上位机之间的数据通信和制动检测软件的开发等方面进行了系统论述。最后对远程检测系统进行了试验论证。结果表明该设计方案基本上是成功的。该设计方法对于提高汽车综合性能检测站的服务水平具有一定的参考意义。     

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.     

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.     

Non-monotonic material contrast in scanning ion and scanning electron images

30 keV Ga⁺ focused ion beam induced secondary electron (iSE) imaging was used to determine the relative contrast between several materials. The iSE signal compared from C, Si, Al, Ti, Cr, Ni, Cu, Mo, Ag, and W metal layers does not decrease with an increase in target atomic number Z₂, and shows a non-monotonic relationship between contrast and Z₂. The non-monotonic relationship is attributed to periodic fluctuations of the stopping power and sputter yield inherent to the ion–solid interactions. In addition, material contrast from electron-induced secondary electron (eSE) and backscattered electron (BSE) images using scanning electron microscopy (SEM) also shows non-monotonic contrast as a function of Z₂, following the periodic behavior of the stopping power for electron–solid interactions. A comparison of the iSE and eSE results shows similar relative contrast between the metal layers, and not complementary contrast as conventionally understood. These similarities in the contrast behavior can be attributed to similarities in the periodic and non-monotonic function defined by incident particle–solid interaction theory.     

Application of Feature Extraction through Convolution Neural Networks and SVM Classifier for Robust Grading of Apples

This paper proposes a novel grading method of apples,in an automated grading device that uses convolutional neural networks to extract the size,color,texture,an...