Stiffness matrix derivation of space beam element at elevated temperature

Element stiffness equation is very important in structural analysis, and directly influences the accuracy of the results. At present, derivation method of element stiffness equation is relatively mature under ambient temperature, and the elastic phrase of material stress-strain curve is generally adopted as physical equation in derivation. However, the material stress-strain relationship is very complicated at elevated temperature, and its form is not unique, which brings great difficulty to the derivation of element stiffness equation. Referring to the derivation method of element stiffness equation at ambient temperature, by using the continuous function of stress-strain-temperature at elevated temperature, and based on the principle of virtual work, the stiffness equation of space beam element and the formulas of stiffness matrix are derived in this paper, which provide basis for finite element analysis on structures at elevated temperature.     

关于铁路冷藏运输冰冷车更新换代产品的设想

B6型和B6A型冰冷车是铁路冷藏运输冰冷车的主型车。该车具有结构简单、成本低和有加冰站(全国性的辅助系统)等优点，但其在冰中加盐的作法易腐蚀车辆及轨道，而且该型车已经到了或接近报废期。因此，铁路冷藏运输冰冷车更新换代问题应提到议事日程上来。     

Periods and energy dissipations of a novel TLD rectangular tank with angle-adjustable baffles

A novel tuned liquid damper (TLD) rectangular tank with two angle-adjustable baffles was presented. The numerical analysis was performed using the commercial code FLUENT. The standard kinetic energy and dissipation rate turbulent model was employed, which was solved using volume of fluid (VOF) method able to treat both the free surface motion and the viscous stresses over the rigid walls accurately. The relationship between the natural periods of water and the angles of its baffles was studied by numerical sim- ulating of a case, and the changes of energy dissipations were investigated. The natural periods and dampers of the novel TLD can be changed in a wide range by adjusting the baffles' angle, thus it is more effective in controlling the vibration of structures in a wide frequency range.     

交流发电机与充电指示电路的2种适配方法

在对汽车进行大修时,常会遇到购买不到与原车电路相适配的仪表板总成的情况,只得用新式的仪表板总成进行代换,主要的问题是原车使用的6只整流管式交流发电机无中性点接柱,由电流表指示充放电情况,而新换的仪表板总成基本上都是使用带中性点线或专用励磁二极管控制的充电指示电路,由充电指示灯指示充放电情况.下面介绍2种交流发电机与充电指示灯的适配方法.     

Risk-identification-based hybrid method for estimating the system reliability of existing jacket platforms under fire

This paper proposes a risk-identification-based hybrid method for estimating the system reliability of steel jacket structures under fire.The proposed method starts with risk identification;according to the results of hazard identification and Dow’s fire and explosion index(F&EI) methodology,the most dangerous hazard sources are determined.In term of each equipment layout in steel jacket structures,fire load is imposed and elasto-plastic analysis is performed.According to the deformed state of steel jacket structures,the weakest failure mode of steel jacket structures is identified.In order to know the effect on ultimate bearing capacity of the offshore structural system,a series of elasto-plastic analyses are performed in which single failure element contained in the weakest failure mode is removed from the whole offshore platform structural system.Finally,the failure function of the steel jacket structure is generated and the failure probability of the steel jacket structure system is estimated under fire by genetic algorithm via MATLAB program.