摘 要


汽車市場的激烈競爭，促使生產(chǎn)廠家極大的縮短了產(chǎn)品的開發(fā)周期；發(fā)動機朝著增壓、高功率、輕量化方向的迅速發(fā)展，又使研究員更加注重發(fā)動機結(jié)構(gòu)的改進?；钊鳛榘l(fā)動機的心臟，是一種技術(shù)含量比較高的零部件。由于其工作條件惡劣，高的機械負(fù)荷和熱負(fù)荷常常導(dǎo)致活塞銷座的開裂、環(huán)槽的早期磨損、活塞頂面燃燒室喉口邊緣熱裂等故障。因此有必要對活塞進行有限元分析計算，掌握活塞熱應(yīng)力和機械應(yīng)力的分布規(guī)律，為活塞的設(shè)計提供有力的依據(jù)?；钊脑O(shè)計方法隨著社會的不斷發(fā)展出現(xiàn)了各種先進的設(shè)計、試驗和工藝手段，如有限元技術(shù)在設(shè)計上大幅度的提高了活塞的強度；活塞的溫度場有限元分析，能非常準(zhǔn)確的模擬活塞的實際工作環(huán)境溫度。使發(fā)動機的功率不斷的增加，尾氣的排放相對以前也得到了較大的改進，提高了設(shè)計的效率和科學(xué)性。
本文總結(jié)了活塞設(shè)計的基本規(guī)律，利用UG建立活塞的幾何模型?？紤]了活塞軸對稱性，建立了活塞的四分之一有限元模型。采用有限元分析的方法對設(shè)計的活塞進行了溫度場和熱應(yīng)力的耦合分析，最后對設(shè)計的活塞分析后作出評價并獲得了合理的結(jié)果。結(jié)果表明活塞在頂部以熱應(yīng)力為主，在裙部以機械應(yīng)力為主。作為活塞熱負(fù)荷評價的重要依據(jù)的第一環(huán)槽溫度在165～215 ，不會因溫度過高而影響氣環(huán)的密封性（活塞用高溫潤滑油的結(jié)膠溫度為220 ）。通過對活塞的三維建模和有限元分析的實例體現(xiàn)出計算機輔助工程技術(shù)在產(chǎn)品設(shè)計初期的優(yōu)性：即一方面建立了基本的計算機分析模型，對其進行仿真模擬，從而指導(dǎo)產(chǎn)品的設(shè)計；另一方面以此為虛擬分析平臺并提供一些規(guī)范性或經(jīng)驗性的建模參考，同時也為提高了企業(yè)在技術(shù)上的自主開發(fā)及創(chuàng)新能力而奠定基礎(chǔ)。


關(guān)鍵詞：活塞，溫度場，熱應(yīng)力，強度,有限元









ABSTRACT

The great competition of automobile market has urged the factories to shorten the product development time; with the development of turbo,high power and light engine,the researchers have paid more attentions on the structure than the past. The piston with high technology is the critical part of engine.The work condition of the pistion becomes more and more rigorous.Heavy mechanical load and thermal load often lead to breakage such as the pistion pin hoss split,ring groove wear and tear,combustion chamber throat rim thermal fatigue crack,etc.so,FEA should be done in order to find the distribution rule of thermal stress and mechanical stress of the pistion,and provide reference to improveing design pistion.With the development of the society,many advanced design methods ,test methods and technics have appeared.For example,the FEA technique can improve the strength of the designing pistion greatly,the FEA of the pistion’s temperature field can simulate the real of the work condition of the pistion correctly. It makes engine’s power high, exhaust gas greatly improve, the efficiency of the design increase.
This paper summarizes the design of the basic rules of pistion, the text make used of UG to establish the geometric models of pistion . For the symmetry axis of pistion, build up a quarter of a finite element model of the Pistons. The analysis of a temperature and the coupling of heat stress of the Pistons With the finite element methods. The finally we give an eva luation of the Pistons and analysis was a reasonable outcome. The result reveals that the thermal stress is prominent in the piston head,and the mechanical stress is prominent in the skirt of piston. The first groove of Piston’s temperature as an important basis for the eva luation of Piston’s thermal load is 165 to 215 , which does not affect the tightness of the pistion’s ring(pistion’s plastic high-temperature lubricant temperature is 220 ). Through the analysis of the three-dimensional modeling and finite element of pistion ,it shows the superiority of computer-aided engineering technology in the the early product design. On the one hand,it is the establishment of a basic computer model, its simulation, thus guiding the design of the products; On the other hand ;it can provide some normative or empirical modeling reference to virtual platform, and enhance technical development and innovation capacity for the enterprises.


Key words：pistion,Temperature Field,Thermal Stress,Intensity ,FEM



































目 錄

中文摘要......................................................................................................Ⅰ
ABSTRACT.................................................................................................Ⅱ
1緒論............................................................................................................1
1.1 概述……………………………………………………………………1
1.2 國內(nèi)外概況及發(fā)展趨勢................................................................................1
1.2.1 活塞的結(jié)構(gòu)形式....................................................................................1
1.2.2 國內(nèi)外的研究狀況................................................................................3
1.3 本文研究的內(nèi)容.........................................................