基于热点应力法的履带起重机臂架寿命评估

发布时间：2018-04-12 00:19

本文选题：履带起重机 + K型管　；参考：《大连理工大学》2014年硕士论文

【摘要】：K型管结构广泛应用于履带起重机的臂架中,由于起重机在工作过程中交替进行吊载和卸载,臂架弦腹杆相交而成的K型管焊接区域承受拉压复合载荷,其疲劳强度决定着起重机能否安全工作。因此,针对起重机臂架中的K型管接头进行抗疲劳设计显得尤为重要。本文基于热点应力法,以履带起重机臂架底节危险部位的K型管为研究对象,对典型载荷形式下的臂架进行寿命评估,得到了适用于该种载荷形式下的寿命评估理论算法。论文的主要工作及成果如下： (1)采用有限元软件ANSYS对某型号25t轮胎起重机进行数值分析,得到了臂架的危险部位,并用应力测试试验加以验证。 (2)详细介绍K型管的有限元建模方法,对比不同的单元类型以及网格尺寸对热点应力的影响。提出了一种更加适合批量化建模的焊缝模拟方法,并采用APDL语言进行参数化建模。 (3)建立了45个适应于履带起重机桁架臂几何参数的K型管有限元模型,按照臂架的典型受力方式进行数值分析,并考虑弯曲次应力的影响,得到了K型管焊缝周围应力集中系数随几何参数的分布规律,为臂架的抗疲劳设计提出相应建议。 (4)对热点应力集中系数(SCF)进行非线性回归,得到了SCF关于几何参数τ、β、γ以及φ的参数拟合公式,并对参数公式进行了误差分析。 (5)利用MATLAB软件实现本文算法的可视化操作,能够快速直观地对不同规格的臂架进行典型载荷形式下的寿命评估,为工程实践提供参考。
[Abstract]:The K-type pipe structure is widely used in the jib of crawler crane. Because the crane alternately hoist and unload during the working process, the welded area of K-type pipe with the jib chord webs intersecting is subjected to the composite load of tension and compression.Its fatigue strength determines whether the crane can work safely.Therefore, it is very important to design K-type pipe joints in crane jib.Based on the hot spot stress method, this paper takes the K-shaped pipe at the dangerous part of the bottom joint of the crawler crane as the research object, evaluates the life of the jib under the typical load form, and obtains the theoretical algorithm of life evaluation suitable for this kind of load form.The main work and results are as follows:1) numerical analysis of a 25t tire crane is carried out by using finite element software ANSYS, and the dangerous position of the boom is obtained, which is verified by stress test.The finite element modeling method of K type tube is introduced in detail, and the effect of different element types and mesh size on hot spot stress is compared.A welding seam simulation method is proposed, which is more suitable for mass modeling, and parameterized modeling is carried out by using APDL language.In this paper, 45 finite element models of K-tube are established, which are suitable for geometric parameters of truss arm of crawler crane. Numerical analysis is carried out according to typical stress mode of boom, and the influence of bending secondary stress is considered.The distribution of the stress concentration factor around the weld seam of K-shaped pipe with geometric parameters is obtained, and the corresponding suggestions for the anti-fatigue design of the jib are put forward.(4) the nonlinear regression of the stress concentration factor of hot spots is carried out, and the fitting formulas of parameters 蟿, 尾, 纬 and 蠁 of SCF are obtained, and the error analysis of the formula is given.5) the visual operation of this algorithm is realized by using MATLAB software, which can evaluate the life of the boom of different specifications under typical load forms quickly and intuitively, and provide a reference for engineering practice.
【学位授予单位】：大连理工大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TH213.7

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