【作者】 许烨茹；

【导师】 刘佐民；

【作者基本信息】 武汉理工大学 ， 机械工程， 2012， 硕士

【摘要】 气门-气门座作为发动机的重要摩擦副,其匹配性能直接影响了它的寿命及动力学性能。基于此,如何就其工况特征,选择材料就显得非常重要。本文基于目前气门-气门座常用的材料和复层结构,通过分析其接触特性,研究了其材料的匹配性能,探讨了设计原则及具体的结构形式。本文在分析气门摩擦副工况条件对气门和气门座材料要求的基础上,分析了这对摩擦副的材料匹配性特征。为了建立匹配性接触模型,论文编制出动力学分析人机界面,该系统对气门落座结构进行了参数化设置,运用MATLAB软件平台将气门结构参数输入,即可绘制出需要的气门运动曲线。通过该系统就能调用MATLAB计算程序,对气门机构动力学进行分析,提高了气门-气门座接触分析的效率和可靠性。与此同时,本文采用Ansys/Ls-dyna软件平台,基于动态接触理论建立了气门-气门座摩擦副碰撞接触仿真分析模型,并以几种气门座熔覆层材料为典型实例,分析了其在落座过程中的等效应力分布,研究表明：材料性能参数和复层厚度对冲击接触的等效应力影响较大,材料弹性模量E和密度ρ的匹配性对等效应力的影响很大,并呈现非线性关系；复层厚度h对等效应力σN的影响也很大,且也存在着非线性现象。最后对于所讨论的几种复层材料而言,TiO2在层厚0.6mm时是其优化值。本文基于Ansys软件平台仿真模拟分析了气门工况对其匹配性的影响,探讨了使用匹配副相互冲击作用时的接触表面力分布,力图寻优合理的设计方法,为其工程应用提供依据。更多还原

【Abstract】 As an engine friction pair, the valve-valve seat is important. Its matching performance directly affects the dynamic performance and its life. Based on this, how to choose material under the condition characteristics is very important. This article discusses the design principle and the structure of the specific form based on the present valve-valve seat commonly used material and complex layer structure by analyzing the characteristics of contact and the matching of the material properties.This article analyzes the friction pair matching material properties based on the working conditions of valves and valve seat material requirements. In order to establish matching contact model, this paper constructed dynamics analysis interface. Setting the valve parameter, inputting valve structure parameters by using MATLAB software platform, can draw the need of valve movement curve. Through this system we can call MATLAB program, analyze the valve dynamic, improve the analysis of the contact of valve-valve seat the efficiency and reliability.At the same time, this paper using Ansys/ls-dyna software platform establish the pair of friction collision contact simulation model based on dynamic contact theory, and with several valve seat plate department cladding layer as a typical case, analyzed the effective stress distribution in the process of the drop test. Research shows that: the material properties and complex thickness affect equivalent stress much, for example, the matching of material elastic modulus E and density p influence the forces σn much, and presents the nonlinear relationship; Layer thickness h equivalence effect force σn has a very big impact, and also has the nonlinear phenomenon. For the final discussed several complex layer material character, TiO2in a thick layer of0.6mm is the best.This paper based on Ansys software platform simulates the influence of valve working condition to the matching, and discusses the contact surface force distribution when the use matching, and tries to find reasonable design methods, for the engineering application.更多还原