利用光弹性应力分析法研究连杆

可将连杆作为实验应力分析法的一种有价值的应用方面。连杆是发动机活塞和曲轴之间的传动零件,因此在设计时不仅要正确考虑应力问题,而且为了保证两个零件轴承处的润滑性,轴承部分必须有一定的刚度。此外,在设计连杆时还必须考虑制造问题。作为发动机的运动件,连杆影响轴承、曲轴和曲轴箱壁所承受的惯性力负荷,因此,最好在发动机初步设计阶段就考虑合适的连杆形状,以便能够正确设计承受惯性力的零件。     

复合材料连杆的开发

内容提要设计并制造FP纤维-金属复合材料连杆可以减小发动机振动.     

根据咬瓦与磨损分析预测连杆轴瓦可靠性的方法

<正> 1 引言确保连杆轴瓦的可靠性已经成为当今汽车发动机研究工作中一个极其重要的问题。这是因为汽车发动机正向高速、高性能的方向发展,发动机结构更为轻巧紧凑,连杆轴瓦的工作条件正日益变得更加苛刻(图1)。防止连杆轴瓦的损坏,包括很多与发动机设计和制造有关的因素(图2),它牵涉到各个零件的尺寸配合和制造公差,还必须考滤与总体系统有关的问题,例如是否要滑油冷却器等。     

轿车发动机高强度连杆开发

采用计算机辅助设计(CAE)方法设计了轿车发动机用轻量化、高强度连杆;通过有限元计算分析,该连杆不存在失稳危险,并符合强度要求;用液压伺服疲劳试验系统进行疲劳试验,连杆安全系数满足设计要求;通过严格控制生产加工工艺,提高制造加工质量,实现了该连杆的批量生产.     

国外发动机连杆生产现状

国外发动机连杆生产现状机械部第三设计研究院何约洁目前连杆毛坯主要的制造方法有铸造、模锻和粉末冶金，并研制和开发复合材料连杆等。１铸造连杆铸造连杆材料多为珠光体可锻铸铁。其化学成分大致为：２．６％Ｃ、１．４％Ｓｉ，０．４２％Ｍｎ，其余为Ｆｅ。热处理后的...     

塑料发动机

【美刊《汽车工业》1980年12月报道】正当世界上许多汽车制造厂家大谈用塑料制造阀套、油槽、交流发电机底座、甚至化油器的时候,美国白利发动机研究公司的霍尔兹伯格却在美国新泽西州的拉姆齐研制成功采用90%塑料复合材料制造的四缸发动机。为什么采用塑料,而不采用铝、钢或钛制造呢?霍尔兹伯格说:“因为在设计、制造性能先进的发动机时,铝承受应力的能力差,钢太重,钛太贵”。该公司在试制塑料发动机的过程中首先试制的是塑料活塞,然后试制塑料连杆、塑料推杆。至今该公司已销售10000根塑料连杆,20000根塑料推杆,还为美国底特律和外国的一些主要汽车公司和发动机公司提供了许多复合材料的原型发动机毛坯。     

发动机连杆材料及工艺

连杆轻量化的途径主要是制造工艺和材料的改进.本文对发动机连杆工艺和材料进行了较全面的分析论述,指出了今后连杆工艺和材料的应用发展趋势.     

490发动机连杆组件非线性接触有限元分析

连杆组件作为发动机动力传动中的重要组成部分,是发动机设计及改进中的关键部件。用MSC/MARC对490发动机连杆组件进行三维非线性接触计算,确定其应力应变场。为其设计改进和发动机性能提高提供分析基础。     

基于ANSYS的连杆的三维有限元分析

用有限元软件ANSYS对某军用发动机连杆进行了三维有限元分析,确定了连杆的最大应力部位和疲劳安全系数,为此发动机连杆的可靠性设计提供了依据.     

490发动机连杆组件非线性接触有限元分析

连杆组件作为发动机动力传动中的重要组成部分,是发动机设计及改进中的关键部件.用MSC/MARC对490发动机连杆组件进行三维非线性接触计算,确定其应力应变场.为其设计改进和发动机性能提高提供分析基础.     

活塞抗疲劳研究现状及展望

发动机活塞疲劳强度的提升一直是发动机技术研究的重点,主要介绍了发动机活塞抗疲劳的研究进展,从活塞材料、工艺及结构方面的改进进行了总结,对其未来的发展做了展望并提出了一些建议。     

6CTA柴油机与发电机组冷却系统优化

通过对某160kW发电机组匹配6CTA柴油机后的高水温故障调查,开展了冷却系统的设计优化,包括冷却风扇、散热器及湿式排气管等,最终通过试验验证了设计优化方案是可行的,从而解决高水温故障。     

一种环保型燃油滤清器的开发

国家实行GB17691—2005排放法规后，根据燃油滤清器在实际使用中出现的问题．针对中国市场的具体情况和用户的需求，开发的环保型滤清器，达到了产品质量提升和成本降低的“双赢”结果，总结环保型滤清器的开发思路和步骤。     

具有自动泵油功能的滤清器设计原理

目前国内外市场上，柴油滤清器总成上集成的泵油装置全部为手动泵，必须用手向下压送手动泵盖，使泵室内的膜片上下运动，通过进油和出油两个单向阀的作用在泵室内形成真空．实现手动泵油功能；自动泵柴油滤清器具有自动泵油功能，可排空发动机燃油系统中的空气，自动将燃油从油箱泵至喷油器，实现泵油功能由电动代替手动，大大减轻了泵油的劳动强度，使产品更具加人性化。     

6BTAA发动机前端轮系设计开发

本文介绍了6BTAA发动机前端轮系设计开发过程。根据OEM要求,将装载机用6BTAA发动机的风扇传动比由1．1：1降低为0．87：1。对此,文中详细地描述了设计方案、设计输入、设计计算及试验验证等。试验结果表明,通过降低发动机前端轮系的风扇传动比,可有效地降低装载机的机外辐射噪声,从而满足OEM技术要求。     

YH31材料活塞环工作应力设计限值试验研究

在进行活塞环参数设计时,一般均需要对其工作应力进行校核,通常人们都认为其安全系数应该不低于1.5,即工作应力不超过材料抗弯强度极限值0.67倍的设计是安全可靠的。为什么使用这样的评判标准？本文用活塞环疲劳强度试验的方法,对YH31材料无镀层活塞环进行试验研究,希望探索出其工作应力的设计极限值。试验研究表明,对于YH31材料无表面镀层活塞环,工作应力设计值不超过材料抗弯强度极限值的0.60倍是适宜的。     

Non-Linear Thermal Stability Analysis of SMA Wire-Embedded Hybrid Laminated Composite Timoshenko Beams on Non-Linear Hardening Elastic Foundation

In the present study, non-linear thermal post-buckling analysis of hybrid laminated composite Timoshenko beams embedded with the shape memory alloy (SMA) wires resting on a non-linear hardening elastic foundation were studied. Mechanical properties of composite media are considered temperature-dependent. The theory of Timoshenko beams and von Kármán's strain-displacement relations are applied simultaneously in virtual work principles to derive the system of non-linear equilibrium equations. Various types of boundary conditions such as clamped, simply supported, and rolled edges were studied for edge supports. Generalized Differential Quadrature Method (GDQM) was utilized to discrete the equilibrium equations in space domain. Different types of lay-ups, such as symmetric and asymmetric, were considered. Post-buckling paths are depicted for different values of non-linear elastic foundation parameters, volume fractions, pre-strains of the SMA fibers, and boundary conditions. The one-dimensional thermo-mechanical constitutive law suggested by Brinson [1 L. C. Brinson , One-Dimensional Constitutive Behavior of Shape Memory Alloys: Thermomechanical Derivation with Non-Constant Material Functions and Redefined Martensite Internal Variable , Journal of Intelligent Material Systems and Structures , vol. 4 , no. 2 , pp. 229 – 242 , 1993 .[Crossref] , [Google Scholar]] is applied to model the SMA wires. Numerical results make it possible to recognize that increases in the volume fraction and pre-strain of SMA lead to a dramatic enhancement in thermal buckling and post-buckling capacity of the beam. Pre-buckling, buckling, and post-buckling behavior of the beam are totally different and this is due to variations among critical buckling, austenite start and finish temperatures. Due to the recovery stress of SMA wires, particular consequences are shown.     

Taxonomies of SOFC material and manufacturing alternatives

Material and manufacturing alternatives for solid oxide fuel cells are listed and analyzed. Specifically, four categories of anode materials, five categories of cathode materials, four categories of electrolytes, and three categories of interconnect materials are presented. Design considerations including operating temperatures and compatibilities among stack materials are also highlighted. Similarly, stack manufacturing options are separated into seven categories and developed into process sequences based on the number and type of firing steps. This work is intended to facilitate material and manufacturing assessments through the consideration of the variety of alternatives prior to capital investment for wide-scale production.     

Discussion and study on contraction joints for RCC gravity dam

Based on the construction property of rolled compacted concrete, three-dimensional finite element relocating mesh method was developed in simulating construction process and computing temperature and stress field. Using this method, the temperature and the thermal stress fields developed in the RCC gravity dam of the Longtan project with or without a longitudinal joint during construction and operation are calculated so as to simulate the construction process. The computation results show that the value of the thermal stresses developed in the dam even, without any longitudinal joint, could meet the design criteria provided the placement temperature is adequately controlled.     

Condensation in Horizontal Smooth Tubes: A New Heat Transfer Model for Heat Exchanger Design

This paper proposes a new method to determine the condensation heat transfer coefficient of fluids flowing into horizontal smooth tubes with internal diameters D > 3 mm. The method has been drawn up as simply as possible and is ready to use in heat exchanger modeling and design applications. It is also suitable to work very well with old and new fluids used in the refrigeration, air conditioning, and heat pump industries. Particular attention is given to accuracy: it has been tested over a wide updated experimental database and comes from many different independent researchers with reduced experimental uncertainties. In order to obtain an easy structure, only two equations are employed, related respectively to & Delta; T-independent and to & Delta; T-dependent fluid flows. All the parameters that influence the condensation heat transfer have been included.

A comparison has been conducted against HCFCs, HFCs, HCs, carbon dioxide, ammonia, and water data. Zeotropic mixtures with two and three components are also considered in the comparison by applying the Bell and Ghaly [1 Bell, K. J. and Ghaly, M. A. 1973. An Approximate Generalized Design Method for Multicomponent/Partial Condenser. AIChE Symp. Ser., vol. 69: 72–79. [CSA] [Google Scholar]] correction to calculate the relative heat transfer penalization. A model has been developed with the idea of getting high accuracy through an easy structure, and the results show a very satisfactory agreement with experimental data: average deviation e_R = +2%, absolute mean deviation e_AB = 14%, and standard deviation σ_N = 19% for the total number of 5478 data points.