Experimental study on the behavior of eccentrically loaded circular footing model resting on reinforced sand

In this study, an experimental investigation has been conducted on a circular footing model subjected to eccentric load resting on the geonet-reinforced sand. To this end, five series of tests were carried out in order to evaluate the effect of reinforcement dimension and eccentricity on the bearing capacity, settlement, and rotation of the footing. Results show that the bearing capacity ratio (BCR) is in direct relationship with eccentricity and the impact of soil reinforcement at low settlements is much more significant in the case of eccentric loading. Additionally, the bearing capacity interaction diagram and variation in the position of rotation line at different load levels for reinforced and unreinforced conditions are presented.     

Behaviour of eccentrically loaded high-strength rectangular concrete-filled steel tubular columns

This paper presents an experimental and analytical study of the behaviour of high-strength rectangular concrete-filled steel tubular (CFT) columns subjected to eccentric loading. Four slender and 16 stub CFT columns were tested to investigate their structural behaviour. The test parameters were material strengths (), cross-sectional aspect ratio (1.0-2.0), slenderness ratio (10 and 60) and load eccentricity ratio (e/H=0.10-0.42). Favourable ductility performance was observed for all specimens during the tests. Experimental failure loads are employed to calibrate the specifications in the design codes EC4, ACI and AISC. Results show that EC4 overestimates the failure loads of the specimens by 4%. ACI and AISC conservatively predict the failure loads by 14% and 24%, respectively. An analytical model is developed to predict the behaviour of high-strength rectangular CFT columns subjected to eccentric loading. Calibration of the model against the test results shows that it closely estimates the ultimate capacities of the columns by 3%.     

莱钢产轧制H型钢构件受力性能的理论与试验研究(Ⅰ) H型钢构件偏心受力性能的试验研究

国产热轧H型钢近几年在我国进行了大力的推广和应用 ,它是一种经济性的断面型材 ,这种型材具有翼缘宽大、连接方便、造价低的优点 ,为了研究其力学性能 ,对这种型材在偏心荷载情况下的柱平面内稳定承载力进行了试验 ,介绍了试验情况 ,对同一截面的不同长细比、不同偏心率的 10个试件进行了分析 ,结果表明这种破坏属于典型的极值点失稳问题 ,同时与按《规范》[1 ] GBJ 17 1988计算的理论值进行了对比 ,发现其具有较高的承载能力     

莱钢产轧制H型钢构件受力性能的理论与试验研究(Ⅱ) H型钢构件偏心受力性能的理论与试验研究

利用有限元法对国产热轧H型钢柱在偏心荷载作用下的强轴平面内稳定承载力进行了系统的研究 ,分析过程中考虑了不同截面形式、残余应力等因素的影响 ,并把有限元计算值和按《规范》[1 ] GBJl7 1988计算的理论值进行了对比。通过计算发现规范结果偏保守 ,同时通过试验验证了上述结论 ,最后对《规范》公式提出修正     

轴类偏心零件偏心量测量方法及探测头误差分析研究

针对机械轴类偏心零件偏心量测量问题,提出了一种基于反转法和最小二乘法的偏心量测量方法。分析了影响测量精度的主要因素,并重点研究了探测头测量位置对测量精度的影响。通过对机器人关节减速器中偏心轴零件进行数字模拟,对不同测量位置下偏心量的测量结果和测量误差进行了分析,并给出了其测量误差曲线,为实际测量过程中提高测量精度提供一定的技术支撑。     

射线检测中偏心透照方法探讨

在射线内透偏心法透照中,采用一次贴片,多次曝光,分次取片的检测方法效率高,但是检测人员容易忽视透照厚度比K值的变化,使得K值不符合标准要求。本文通过计算与分析,提出在内透偏心法透照中应首先确定一次最大偏心距离Smax,再通过和实际偏心距离对比,确定曝光方式,并提出在偏心透照方法中为保证底片的黑度和灵敏度应注意的一些问题。     

Numerical Calculations of Wall Pressures and Stresses in Steel Cylindrical Silos with Concentric and Eccentric Hoppers

This article presents finite element (FE) calculations of stresses in a silo structure caused by the loads exerted by the discharging material. Two different conical hoppers were studied, concentric and eccentric withdrawal. The eccentricity was introduced by the change of the outlet position towards one side of the hopper, and the influence of this modification is presented. The simulation of silo flow with the common Drucker-Prager model for bulk solids was performed in order to obtain the wall pressure distribution. All FE calculations are carried out with aid of the commercial software ABAQUS. Significant differences are found in the hopper-wall stresses between the concentric and eccentric cases. Strong bending actions appear in the eccentric hopper, and they are influenced by stiffness of the hopper/cylinder junction.     

水泥电杆模具翘尾问题研究

水泥电杆在离心成型过程中,常遇到模具震动的现象。本文讨论了模具近梢端部分翘起引起模具震动的情况。提出了以限制翘起度来防止模具震动。     

Buckling of shear deformable thin-walled members—I. Variational principle and analyticalsolutions

A variational formulation for the buckling analysis of thin-walled members is developed based on the principle of stationary potential energy. The formulation is based on non-orthogonal coordinates and captures shear deformation effects due to bending and warping. It is applicable to members of doubly symmetric cross-sections subject to general axial and transverse forces and naturally incorporates the effect of load position relative to the shear centre. Applying the conditions of neutral stability to the variational expression, the governing differential equations of neutral stability and associated boundary conditions are formulated. The resulting field equations are exactly solved for benchmark cases involving column flexural buckling, column torsional buckling, and lateral-torsional buckling for beams, and the results are compared to closed form solutions based on classical and other modern theories.     

集成电路塑封模具错位、偏心问题探讨

就集成电路封装过程中塑封模具的错位和偏心问题做探讨,分析导致错位和偏心的各种原因,并就如何使塑封模具的错位、偏心问题对产品的质量影响降到最低提出了具体的改善措施.