法兰密封面腐蚀缺陷超声相控阵检测技术

用于腐蚀介质环境下的法兰,密封面的腐蚀缺陷容易使其泄漏,影响安全生产,导致危害性的后果。利用超声相控阵检测技术[1]声束角度可变和动态聚焦的优点、适合复杂结构件以及实时成像等特点,通过结构分析、声场模拟,试验研究和现场检测应用,确定了法兰超声相控阵针对性检测工艺,实现了不拆卸从法兰外部对密封面腐蚀缺陷进行有效检测。     

高翻边类零件成形工艺仿真优化及试验研究

本文以某汽车结构件前边构件连接板内板为研究对象,针对零件外沿翻边高度大,冲压生产时容易产生破裂的问题,首先分析了影响破裂的主要因素,然后借助板料成形有限元软件Dynaform对相关工序进行了数值模拟,最后得到了拉延高度、侧壁倾角等主要因素对材料最大变薄率的影响规律,并据此指导模具设计与试验.试验结果表明:数值模拟技术能够准确预测成形缺陷,同时指导实际生产并创造经济效益.     

关于Waters法设计法兰方法的考证

Waters法是国际较为通行的法兰设计方法,国家标准GB150中也采用此法。但此方法作了一定的简化假设,导致计算结果与实际存在误差。文章采用有限元计算对该法进行了考证。通过实例计算,对Waters法和有限元法的计算结果进行了比较。结果表明:按Waters法考虑的载荷计算,锥颈变形要比按实际载荷计算的变形小一半,应力小1/3。     

H型钢万能轧制宽展分析

借助有限元分析软件MSC．SuperForm2004对H型钢万能轧制进行了模拟，着重讨论了轧件的万能轧制不同阶段，宽展在孔型中的变化规律，由模拟结果可知万能孔型中轧件翼缘的端部，不接触轧辊；变形主要靠变形渗透，变形量很小；且变形渗透随道次的增加而明显。轧边机孔型中，翼缘的端部也基本不接触轧辊，只是在最后一两道次才对翼缘端部进行加工。合理制定万能压下规程对翼缘压下量的设定可以对翼缘端部的宽展进行有效的控制。     

垫片螺栓法兰连接系统的载荷与变形分析

分别在预紧和操作情况下 ,应用弹性理论对螺栓法兰系统进行了较为详细的载荷 变形分析 ,同时提出了将方程组的求解转化为优化问题 ,应用遗传算法结合牛顿迭代法来求解相关的非线性方程组。算例表明 ,考虑法兰旋转时更能反映螺栓法兰系统的真实受力情况。     

基于AutoCAD ActiveX技术设计标准件法兰

介绍一种在AutoCAD14环境下，利用AutoLISP和AutoCAD ActiveX技术，将标准件法兰尺寸输入数据库、迅速、准确地绘制法兰施工图的技术。     

Cyclic behaviour of unreinforced and rib-reinforced moment connections

This study investigates the cyclic behaviour of the beam-to-column welded moment connections used in steel moment-resisting frames. Two unreinforced welded connections were tested initially to elucidate the behaviour and failure mode. Test results showed that both specimens failed by the brittle fracture of the beam flange, initiated from the root of the weld access hole. Nonlinear finite element analysis was used to identify the causes of the failure. The stress concentration in the weld access hole region has the potential to cause the beam flange to fracture. Analytical results also demonstrated that reinforcing the connection with a single rib can reduce the concentration of stresses at the root of the weld access hole. Further tests of two specimens whose beam flanges were each reinforced by a single rib revealed that the single rib effectively prevents beam flange fracture in the weld access hole region.     

Shear resistance of longitudinally stiffened panels — Part 2: Numerical parametric study

This paper presents the FE analysis of the influence of different parameters on the shear resistance of panels with different arrangements of longitudinal stiffeners. The studied parameters were the stiffener bending stiffness, the panel aspect ratio, the stiffener position, the web slenderness and the flange rigidity. Longitudinal stiffeners of trapezoidal shape were compared to open T-stiffeners. The former proved to be more efficient, since a larger panel resistance is achieved, for which in addition a smaller stiffness of trapezoidal stiffeners is needed. Different features of the new Eurocode rules were verified against the FEA results as well. Three different procedures for the determination of panel slenderness were tested and the reduction of stiffener bending stiffness, prescribed due to a better correlation with tests on open stiffeners, was verified for both closed and open stiffeners. The influence of bending moment was also considered and the verification of shear and bending interaction was discussed. Finally, the flange contribution to shear resistance was critically analysed.     

Ultimate shear strength of long web panels

Both the Basler model and the Rockey model developed during the early 1960s and 1970s predict reasonably well the postbuckling strength of plate girder web panels subjected to pure shear for panels having an aspect ratio (stiffener spacing/web depth) less than or equal to 1.5. The accuracy of these models deviates significantly when applied to panels with an aspect ratio equal to or greater than 3.0. The majority of all steel structures in the world have been designed and built based on these two major theories or their derivatives that recognize the reserve strength afforded by tension field action in the postbuckling stage. However, no single theory has ever emerged that explains the seemingly elusive stress distributions present in web panels during postbuckling until Yoo and Lee shed light on the true mechanics of web panel postbuckling behavior in shear.This paper revisits the validity of an arbitrary limit imposed by Basler on the maximum aspect ratio of a transversely stiffened web panel and develops a new method of predicting the ultimate shear strength of web panels with high aspect ratios.     

基于SolidEdge变量化技术的标准法兰设计

阐述了SolidEdge变量化设计技术的设计思想、设计步骤以及变量表,利用这种技术设计了标准法兰.设计出的法兰可以作为"模板"零件,快速创建各种规格的法兰零件,建立自己的法兰库.最后指出了SolidEdge变量化设计技术的优点.