【摘要】：液壓挖掘機是廣泛應(yīng)用于工程建設(shè)、道路施工、農(nóng)田水利建設(shè)的土方作業(yè)工程機械,其整機由上部回轉(zhuǎn)平臺、下部行走機構(gòu)以及工作裝置三大模塊構(gòu)成。工作裝置是實現(xiàn)其功能的主要模塊,由三組液壓缸的伸縮運動控制。因液壓挖掘機作業(yè)環(huán)境惡劣,作業(yè)對象復(fù)雜,工作裝置作為直接進(jìn)行挖掘作業(yè)的部分,其結(jié)構(gòu)受力情況復(fù)雜多變,能否在服役年限內(nèi)保證結(jié)構(gòu)的疲勞強度是評價液壓挖掘機性能的重要指標(biāo)。工作裝置在設(shè)計時一般采用校核挖掘機處于危險姿態(tài)、使用最大挖掘力挖掘時結(jié)構(gòu)靜強度指標(biāo)的方法,然而工程機械的結(jié)構(gòu)失效很大一部分是由于疲勞破壞,針對這一問題,論文以小型液壓挖掘機為研究對象,結(jié)合計算機仿真與動態(tài)應(yīng)力實驗,計算了工作裝置疲勞危險點的疲勞壽命。使用ADAMS建立液壓挖掘機工作裝置的剛體模型,分析了它的運動學(xué)特性并繪制挖掘軌跡包絡(luò)圖,得出挖掘機的各項性能參數(shù)。利用ADAMS和Ansys建立工作裝置的剛?cè)狁詈戏治瞿Ｐ?模擬典型挖掘循環(huán),獲得了動臂和斗桿的動態(tài)應(yīng)力—時間歷程,為動態(tài)應(yīng)力實驗提供了參考。結(jié)合剛?cè)狁詈戏抡?對挖掘機樣機的工作裝置疲勞危險點進(jìn)行了動態(tài)應(yīng)力測試實驗,實驗數(shù)據(jù)經(jīng)濾波、計算處理后獲得了各點的動態(tài)應(yīng)力—時間歷程,在nCode DesignLife疲勞分析軟件中使用雨流計數(shù)法進(jìn)行了載荷統(tǒng)計,得到用于疲勞壽命估算的疲勞載荷譜。運用古德曼方法修正各級載荷平均應(yīng)力的影響,用線性疲勞累積損傷理論的Miner法則對各點的疲勞壽命進(jìn)行計算,得出了危險點的疲勞壽命。課題研究為液壓挖掘機工作裝置的動態(tài)應(yīng)力仿真以及結(jié)構(gòu)疲勞壽命計算提供了方法指導(dǎo),同時此研究思路和實施方法也可應(yīng)用于其它承受隨機載荷的機械結(jié)構(gòu)的疲勞強度研究。本課題得到建設(shè)機械國家重點實驗室開放基金支持。
[Abstract]:Hydraulic excavator is a kind of earthwork construction machinery widely used in engineering construction, road construction and farmland water conservancy construction. its whole machine is composed of three modules: upper rotating platform, lower walking mechanism and working device. The working device is the main module to realize its function, which is controlled by the telescopic motion of three groups of hydraulic cylinders. Because the working environment of hydraulic excavator is bad and the working object is complex, the working device, as the part of direct excavating operation, has complex and changeable structural force. Whether the fatigue strength of the structure can be guaranteed during the service life is an important index to evaluate the performance of hydraulic excavator. In the design of the working device, the method of checking the excavator's dangerous attitude and using the maximum excavating force to excavate the static strength index of the structure is generally adopted. However, a large part of the structural failure of the construction machinery is due to fatigue failure. Taking the small hydraulic excavator as the research object, combined with computer simulation and dynamic stress experiment, the fatigue life of the fatigue dangerous point of the working device is calculated in this paper. The rigid body model of the working device of hydraulic excavator is established by using ADAMS, its kinematic characteristics are analyzed and the envelope diagram of mining trajectory is drawn, and the performance parameters of excavator are obtained. The rigid-flexible coupling analysis model of the working device is established by using ADAMS and Ansys to simulate the typical mining cycle, and the dynamic stress-time history of the moving arm and bucket rod is obtained, which provides a reference for the dynamic stress experiment. Combined with rigid-flexible coupling simulation, the dynamic stress test experiment is carried out on the fatigue dangerous point of the working device of the excavator prototype. The experimental data are filtered and the dynamic stress-time history of each point is obtained after calculation and processing. The load statistics are carried out by using rain flow counting method in nCode DesignLife fatigue analysis software, and the fatigue load spectrum for fatigue life estimation is obtained. Goodman method is used to correct the influence of load average stress at all levels, and the Miner rule of linear fatigue cumulative damage theory is used to calculate the fatigue life of each point, and the fatigue life of dangerous point is obtained. The research provides a method guide for the dynamic stress simulation and structural fatigue life calculation of the working device of hydraulic excavator. At the same time, this research idea and implementation method can also be applied to the fatigue strength of other mechanical structures subjected to random loads. This topic is supported by the Open Fund of the State key Laboratory of Construction Machinery.
【學(xué)位授予單位】：山東大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：TU621

【引證文獻(xiàn)】

相關(guān)碩士學(xué)位論文 前4條

1 柳明珠;液壓挖掘機斗桿結(jié)構(gòu)的疲勞壽命研究[D];大連理工大學(xué);2018年

2 董可心;斗輪堆取料機臂架疲勞壽命的仿真分析研究[D];吉林大學(xué);2017年

3 李維多;WK-75型機械式挖掘機動臂的疲勞裂紋擴展壽命預(yù)測與分析[D];太原理工大學(xué);2016年

4 李志勇;挖掘機工作裝置力學(xué)分析系統(tǒng)開發(fā)與斗桿載荷譜編制[D];長安大學(xué);2016年

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本文編號：2484973