【作者】 兰雁；

【导师】 雷宏刚；

【作者基本信息】 太原理工大学 ， 结构工程， 2008， 硕士

【摘要】 焊接空心球节点是我国采用最早也是目前应用较广的一种节点,具有构造简单,传力明确,连接方便等优点。尽管目前对这类节点已有较多的研究,但对于空心焊接球节点的认识还是不够深入和全面的。特别随着实际工程运用的不断发展,这种局限性也逐渐显露出来。本文总结了网架焊接空心球节点疲劳破坏机理和各种影响疲劳破坏的因素,探讨了改善焊接空心球疲劳强度的方法。应力集中是焊接空心球节点发生疲劳断裂最主要的原因。本文以ANSYS有限元软件为研究手段,针对网架焊接空心球节点,采用理想弹塑性应力一应变关系和Von一Mises屈服准则、建立了空心球壁厚与直径、十字板的板厚、十字板与焊接空心球的连接长度这四个几何参数不同变化下的有限元分析模型,得出其节点的应力分布,找到热点位置,并定量求得相应的应力集中系数K_t,并对所得应力集中系数K_t数据进行整理,得出相应的应力集中系数曲线;论述了在十字板上开剖口与不开剖口的焊接空心球节点对于应力集中的影响,并进一步定量分析了在不同焊脚高度下,应力集中系数K_t的变化情况。本文应用数值模拟方法计算分析了十字板与焊接空心球节点的应力分布,克服了试验测量方法费时费力、受许多条件限制等缺点,反过来还能验证试验测试的结果。因此本文的研究成果对科学研究和工程实际都具有一定的参考价值。更多还原

【Abstract】 Welded hollow spherical joints are the earliest used kind of joints in our country , and are widely used for their simple structure , definiteness of load transferring and convenient connection. Although these joints have been extensively investigated , However ,the knowledge about the welded hollow spherical joints is generally shallow and non-overall. With the development of the utilization of the practical engineering, such limitations are graduallycoming out.The most important reason for fatigue fracture of welded hollow sphericaljoints is stress concentration . For the research means for welded hollow spherical joints , this paper Based on ANSYS FEA software and the elastic perfectly plastic model and the Von-Mises yielding criterion, Finite element analysis model are established for the welded hollow spherical joints under different change of the four geometric parameters of hollow spherical wall thick and diameter and connection length of cross plate with welded spherical, Stress distribution of the joints are obtained ,and found the hot spot position ,and quantitative obtained corresponding concentration coefficient K_?. Effect ofstress centralized for the welded spherical joints have discussed upper open Cesarean port and not open Cesarean port on the cross plate. The paper has made the further the change of stress coefficient under the different fillet height and done the quantitative analysis. The stress distribution on welded empty sphere joint with cross plate is calculated in this paper through the FEM, which overcome the shortages of the test methods, and can testify the measuring results of the test methods, and can testify the measuring results of the test methods as well. So it has certain reference value to science research or engineering application.更多还原