本文選題：沖擊載荷　切入點(diǎn)：疲勞分析　出處：《合肥工業(yè)大學(xué)》2013年碩士論文　論文類型：學(xué)位論文

【摘要】：隨著我國經(jīng)濟(jì)建設(shè)的快速發(fā)展,工程機(jī)械在社會(huì)生產(chǎn)中應(yīng)用越加廣泛。類似礦山機(jī)械、土方機(jī)械等,工作環(huán)境較為惡劣,所受載荷隨機(jī)性較大。在工作時(shí),存在著作用時(shí)間短且作用力強(qiáng)的沖擊載荷,且可能在一個(gè)工作循環(huán)中這種沖擊載荷均存在；在一些應(yīng)力較大區(qū)域產(chǎn)生了斷裂損傷,隨著沖擊載荷的不斷作用,裂紋快速擴(kuò)展,在短時(shí)間導(dǎo)致機(jī)械零部件破壞,失去服役能力。開展疲勞強(qiáng)度設(shè)計(jì)研究,探索沖擊載荷作用下的機(jī)械零部件疲勞分析方法,對(duì)提高產(chǎn)品競爭力有重要意義。 本文主要對(duì)沖擊載荷作用下機(jī)械零部件疲勞分析方法進(jìn)行研究,并將此方法應(yīng)用到工程機(jī)械鏟運(yùn)機(jī)動(dòng)臂的疲勞壽命估算當(dāng)中,分析其短時(shí)間失效破壞的原因,并提出優(yōu)化改進(jìn)方案。本文的研究內(nèi)容如下： 首先研究總結(jié)了現(xiàn)有的疲勞分析理論和斷裂力學(xué)疲勞裂紋擴(kuò)展相關(guān)知識(shí),分析了沖擊載荷作用后造成的初始裂紋、對(duì)機(jī)械零部件疲勞裂紋擴(kuò)展壽命的影響；不同斷裂韌性對(duì)疲勞裂紋擴(kuò)展壽命的影響；研究總結(jié)了沖擊載荷下機(jī)械零部件疲勞分析方法、設(shè)計(jì)流程及實(shí)施步驟。 分析了地下鏟運(yùn)機(jī)動(dòng)臂各損傷部位的破壞原因,將本文提出的沖擊載荷下機(jī)械零部件疲勞分析方法應(yīng)用于鏟運(yùn)機(jī)動(dòng)臂疲勞壽命分析問題,并提出優(yōu)化改進(jìn)方案；其中對(duì)鏟運(yùn)機(jī)動(dòng)臂進(jìn)行受力計(jì)算、有限元分析及損傷部位疲勞強(qiáng)度校核；并基于線性和非線性疲勞累積損傷理論進(jìn)行了無沖擊載荷作用下的疲勞壽命估算。 基于非線性有限元分析軟件,對(duì)地下鏟運(yùn)機(jī)動(dòng)臂進(jìn)行了沖擊動(dòng)力學(xué)分析,獲取動(dòng)臂沖擊載荷作用下各損傷部位受力情況,應(yīng)用斷裂力學(xué)相關(guān)知識(shí)對(duì)各損傷部位進(jìn)行了疲勞裂紋擴(kuò)展壽命估算,預(yù)測(cè)其可能含有的初始裂紋長度,分析沖擊載荷對(duì)動(dòng)臂損傷的影響,提出初步的動(dòng)臂優(yōu)化改進(jìn)方案。
[Abstract]:With the rapid development of economic construction in our country, construction machinery is more and more widely used in social production. Similar to mine machinery and earthmoving machinery, the working environment is relatively bad, and the load is random. There exists impact load with short time and strong force, which may exist in a working cycle, and fracture damage occurs in some areas with large stress, and the crack grows rapidly with the continuous action of impact load. It is of great significance to develop the fatigue strength design research and explore the fatigue analysis method of mechanical parts under impact load to improve the competitiveness of products. In this paper, the fatigue analysis method of mechanical parts under impact load is studied, and the method is applied to estimate the fatigue life of the moving arm of construction machinery scraper, and the causes of its short-time failure are analyzed. The research contents of this paper are as follows:. Firstly, the existing theory of fatigue analysis and the related knowledge of fatigue crack propagation in fracture mechanics are summarized, and the effect of initial crack caused by impact load on fatigue crack propagation life of mechanical parts is analyzed. The effects of different fracture toughness on fatigue crack propagation life are studied and summarized, and the fatigue analysis method, design process and implementation steps of mechanical parts under impact load are summarized. In this paper, the failure reason of the damaged parts of the moving arm of the underground scraper is analyzed, and the fatigue analysis method of the mechanical parts under the impact load is applied to the fatigue life analysis of the moving arm of the scraper, and the optimization and improvement scheme is put forward. The load-bearing calculation, finite element analysis and fatigue strength checking of the damaged parts are carried out, and the fatigue life is estimated without impact load based on the linear and nonlinear fatigue cumulative damage theory. Based on the nonlinear finite element analysis software, the impact dynamics analysis of the moving arm of the underground scraper is carried out, and the stress situation of the damaged parts under the impact load of the moving arm is obtained. Based on the knowledge of fracture mechanics, the fatigue crack propagation life is estimated, the initial crack length is predicted, the effect of impact load on the damage of the arm is analyzed, and a preliminary scheme for optimization and improvement of the arm is put forward.
【學(xué)位授予單位】：合肥工業(yè)大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2013
【分類號(hào)】：TH114

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本文編號(hào)：1569618