塔式起重机的疲劳寿命预测技术研究
发布时间：2019-01-07 13:27
【摘要】：塔式起重机是建筑施工中最主要的的起重设备，其安全运行时间是评价疲劳寿命的重要指标。随着我国建筑业飞速发展，塔式起重机的满载率加大，工作繁忙程度加重，，塔机出事故越来越频繁。通过对这些事故分析发现有相当一部分是由于结构的疲劳破坏引起的。并以QTZ4510塔式起重机为例，对其进行了疲劳寿命的预测研究。主要进行了以下研究工作。 研究了国内外塔式起重机疲劳研究的现状，根据塔式起重机的载荷特性和使用频率得出了其疲劳类型为高周疲劳。根据其疲劳类型，选用基于名义应力法的虚拟疲劳实验法对QTZ4510塔式起重机的金属结构进行疲劳寿命预测；研究了有限元分析方法的基本理论，通过静力学分析结果和实际统计一个周期内各工况的工作频率，在nSoft疲劳分析软件中进行雨流统计，对得到的应力历程进行应力谱编制，并对其应力谱进行外推；依据Goodman等寿命曲线的假设，将得到的应力谱的非对称应力循环转换为均值为0的应力循环，统计出各级应力循环的次数。根据实际应力集中状况和载荷情况计算塔机材料Q235的双对数坐标P—S—N(应力一寿命)曲线，结合应力谱，在nSoft中进行疲劳寿命预测分析，并分析了影响其疲劳寿命的各因素；并根据编制的应力谱运用灰色系统的预测方法对塔机疲劳寿命进行了预测，验证了其预测的精度；最后预测了塔机起重臂疲劳裂纹的扩展寿命，并提出起重臂疲劳裂纹安全检测周期。
[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.
【学位授予单位】：西安建筑科技大学
【学位级别】：硕士
【学位授予年份】：2012
【分类号】：TH213.3
本文编号：2403717
[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.
【学位授予单位】：西安建筑科技大学
【学位级别】：硕士
【学位授予年份】：2012
【分类号】：TH213.3
【引证文献】
相关硕士学位论文 前1条
1 张新峰;起重机桁架臂疲劳全寿命评估与分析[D];大连理工大学;2013年
本文编号：2403717
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