【摘要】：驅(qū)動橋殼作為裝載機的關(guān)鍵零部件,承受來自路面和裝載機本身的各種沖擊和作用力,其剛度和強度對于主減速器和差速器齒輪的正常嚙合及半軸的正常工作有著重要意義。裝載機的作業(yè)工況復雜,驅(qū)動橋殼所承受的外部載荷是隨時間而變化的動態(tài)隨機載荷。因此,橋殼的主要破壞形式是交變載荷作用下?lián)p傷長期積累而導致的疲勞失效。本文結(jié)合浙江省科技廳重大科技專項項目(2009C11111)“輪式裝載機驅(qū)動橋關(guān)鍵技術(shù)研究與產(chǎn)業(yè)化”,對ZL50型裝載機驅(qū)動橋殼進行了疲勞壽命預測研究。本文的主要研究內(nèi)容如下: 1)利用大型建模軟件UG建立了橋殼三維實體模型,將該幾何模型導入前處理軟件HyperMesh中進行網(wǎng)格劃分,最終得到橋殼的有限元分析模型。利用ABAQUS對橋殼在臺架試驗載荷和裝載機滿載工況下分別進行了強度有限元分析,獲得了橋殼的應力分布。通過在橋殼表面覆蓋一層很薄的殼單元,為后續(xù)的疲勞分析提供了更為準確的橋殼表面應力。通過比較橋殼臺架疲勞試驗加載頻率和模態(tài)分析獲得的橋殼固有頻率,說明了后續(xù)章節(jié)采用準靜態(tài)疲勞分析法估算橋殼壽命的合理性。 2)根據(jù)橋殼強度有限元分析結(jié)果,確定了橋殼載荷譜的測試方案,測取了橋殼的載荷-時間歷程。對采集到的載荷數(shù)據(jù)進行了較詳細的分析,利用nSoft軟件的數(shù)據(jù)處理模塊,對測試數(shù)據(jù)進行了雨流計數(shù)處理,得到了各采樣測點應力-時間歷程的雨流/損傷直方圖和損傷時間歷程。 3)分別基于有限元法和實測應力,結(jié)合材料的疲勞特性(S-N曲線),選用Miner累積損傷法則,利用nSoft軟件中的疲勞分析模塊,對橋殼進行了疲勞壽命預估,得到了驅(qū)動橋殼疲勞壽命云圖及最低疲勞壽命。 4)為了考察焊縫對橋殼疲勞強度的影響,在橋殼整體疲勞損傷/壽命分析的基礎(chǔ)上,進行了焊縫局部細節(jié)的疲勞分析。應用BS7608標準,分別基于實測應力和有限元法進行了焊縫疲勞壽命預估研究。兩種計算結(jié)果均表明,焊縫的疲勞強度明顯的低于母材的疲勞強度,這和焊接結(jié)構(gòu)的疲勞強度通常取決于焊縫接頭疲勞強度的實際情況是相吻合的。 本文對裝載機驅(qū)動橋殼的載荷譜測試及疲勞壽命研究方法也為其它車輛機械零部件的抗疲勞設(shè)計提供了參考,本文的研究工作具有實用意義和推廣價值。
[Abstract]:As the key parts of the loader, the drive axle housing bears all kinds of impact and force from the road surface and the loader itself. Its stiffness and strength are of great significance to the normal meshing of the main reducer and differential gear and the normal work of the half shaft. The working condition of the loader is complex, and the external load of the drive axle housing is a dynamic random load varying with time. Therefore, the main failure form of bridge shell is fatigue failure caused by long-term accumulation of damage under alternating load. In this paper, the fatigue life prediction of the driving axle housing of the ZL50 loader is studied based on the "key Technology Research and industrialization of the Wheel Loader Drive Axle" (2009C11111) of Zhejiang Science and Technology Department. The main contents of this paper are as follows: 1) the three-dimensional solid model of the bridge shell is established by using the large-scale modeling software UG. The geometric model is imported into the pre-processing software HyperMesh for mesh division, and finally the finite element analysis model of the bridge shell is obtained. The strength finite element analysis of the bridge shell under the load of bench test and full load of loader was carried out by ABAQUS, and the stress distribution of the shell was obtained. By covering a thin shell element on the surface of the bridge shell, it provides a more accurate surface stress for the subsequent fatigue analysis. By comparing the loading frequency of bridge shell fatigue test and the natural frequency of bridge shell obtained by modal analysis, the rationality of using quasi static fatigue analysis method to estimate bridge shell life is explained in the following chapters. 2) according to the results of the finite element analysis of the bridge shell strength, the test scheme of the load spectrum of the bridge shell is determined, and the load-time history of the bridge shell is measured. The load data collected is analyzed in detail, and the rain flow count is processed by using the data processing module of nSoft software. The rain flow / damage histogram and damage time history of the stress-time history of each sampling point are obtained. 3) based on the finite element method and the measured stress, combined with the fatigue characteristics of the material (S-N curve), the fatigue life of the bridge shell is predicted by using the fatigue analysis module of nSoft software and the Miner cumulative damage rule. The fatigue life cloud diagram and the minimum fatigue life of the drive axle shell are obtained. 4) in order to investigate the effect of welding seam on fatigue strength of bridge shell, fatigue analysis of welding seam is carried out on the basis of fatigue damage / life analysis of bridge shell. The fatigue life prediction of weld is studied by BS7608 standard based on measured stress and finite element method. The results show that the fatigue strength of weld is obviously lower than that of base metal, which is consistent with the fact that the fatigue strength of welded structure usually depends on the fatigue strength of weld joint. This paper provides a reference for the load spectrum test and fatigue life research of the driving axle housing of the loader. The research work in this paper is of practical significance and popularization value for the anti-fatigue design of other vehicle mechanical parts.
【學位授予單位】：浙江理工大學
【學位級別】：碩士
【學位授予年份】：2011
【分類號】：TH243

【引證文獻】

相關(guān)碩士學位論文 前1條

1 韓龍海;載重車驅(qū)動橋總成動態(tài)特性分析研究[D];青島理工大學;2013年

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本文編號：2415255