【摘要】：塔式起重機(jī)是建筑施工中最主要的的起重設(shè)備，其安全運行時間是評價疲勞壽命的重要指標(biāo)。隨著我國建筑業(yè)飛速發(fā)展，塔式起重機(jī)的滿載率加大，工作繁忙程度加重，，塔機(jī)出事故越來越頻繁。通過對這些事故分析發(fā)現(xiàn)有相當(dāng)一部分是由于結(jié)構(gòu)的疲勞破壞引起的。并以QTZ4510塔式起重機(jī)為例，對其進(jìn)行了疲勞壽命的預(yù)測研究。主要進(jìn)行了以下研究工作。 研究了國內(nèi)外塔式起重機(jī)疲勞研究的現(xiàn)狀，根據(jù)塔式起重機(jī)的載荷特性和使用頻率得出了其疲勞類型為高周疲勞。根據(jù)其疲勞類型，選用基于名義應(yīng)力法的虛擬疲勞實驗法對QTZ4510塔式起重機(jī)的金屬結(jié)構(gòu)進(jìn)行疲勞壽命預(yù)測；研究了有限元分析方法的基本理論，通過靜力學(xué)分析結(jié)果和實際統(tǒng)計一個周期內(nèi)各工況的工作頻率，在nSoft疲勞分析軟件中進(jìn)行雨流統(tǒng)計，對得到的應(yīng)力歷程進(jìn)行應(yīng)力譜編制，并對其應(yīng)力譜進(jìn)行外推；依據(jù)Goodman等壽命曲線的假設(shè)，將得到的應(yīng)力譜的非對稱應(yīng)力循環(huán)轉(zhuǎn)換為均值為0的應(yīng)力循環(huán)，統(tǒng)計出各級應(yīng)力循環(huán)的次數(shù)。根據(jù)實際應(yīng)力集中狀況和載荷情況計算塔機(jī)材料Q235的雙對數(shù)坐標(biāo)P—S—N(應(yīng)力一壽命)曲線，結(jié)合應(yīng)力譜，在nSoft中進(jìn)行疲勞壽命預(yù)測分析，并分析了影響其疲勞壽命的各因素；并根據(jù)編制的應(yīng)力譜運用灰色系統(tǒng)的預(yù)測方法對塔機(jī)疲勞壽命進(jìn)行了預(yù)測，驗證了其預(yù)測的精度；最后預(yù)測了塔機(jī)起重臂疲勞裂紋的擴(kuò)展壽命，并提出起重臂疲勞裂紋安全檢測周期。
[Abstract]:Tower crane is the most important lifting equipment in building construction, and its safe running time is an important index to evaluate fatigue life. With the rapid development of the construction industry in our country, the full load rate of tower crane is increasing, and the busy degree of work is becoming more and more serious, and the accidents of tower crane are more and more frequent. Through the analysis of these accidents, it is found that some of them are caused by the fatigue failure of the structure. Taking QTZ4510 tower crane as an example, the prediction of fatigue life is carried out. Mainly carried out the following research work. The present situation of fatigue research of tower crane at home and abroad is studied. According to the load characteristics and frequency of tower crane, the fatigue type of tower crane is found to be high cycle fatigue. According to its fatigue type, the virtual fatigue test method based on nominal stress method is used to predict the fatigue life of metal structure of QTZ4510 tower crane. The basic theory of finite element analysis method is studied. Through static analysis results and actual statistics of the working frequency of each working condition in a period, rain flow statistics are carried out in nSoft fatigue analysis software, and the stress spectrum of the obtained stress history is compiled. The stress spectrum is extrapolated. According to the assumption of the Goodman equal life curve, the asymmetrical stress cycle of the stress spectrum is converted to the stress cycle with the mean value 0, and the times of the stress cycles at all levels are calculated. According to the actual stress concentration and load, the double-logarithmic coordinate P-S-N (stress-life) curve of tower crane material Q235 is calculated. Combined with the stress spectrum, the fatigue life prediction analysis is carried out in nSoft. The factors influencing the fatigue life are analyzed. The fatigue life of tower crane is predicted by using the grey system prediction method according to the stress spectrum, and the precision of prediction is verified. Finally, the propagation life of the fatigue crack of the crane boom is predicted, and the safe detection period of the fatigue crack is put forward.
【學(xué)位授予單位】：西安建筑科技大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2012
【分類號】：TH213.3

【引證文獻(xiàn)】

相關(guān)碩士學(xué)位論文 前1條

1 張新峰;起重機(jī)桁架臂疲勞全壽命評估與分析[D];大連理工大學(xué);2013年

本文編號：2403717