Enhanced electrothermal effect of carbon fibrous composites decorated with high conductive carbon nanotube webs

Literature has demonstrated that Carbon Nanotubes (CNTs) can greatly enhance the electrical conductivity and matrix-dominated mechanical properties of fibrous composites. However, electrothermal coupling effect of CNTs on Carbon Fiber Reinforced Plastics (CFRPs) has scarcely been considered. This work prepared and introduced thin and porous CNT webs to the surface or/and interface of a CFRP to enhance its electrothermal properties. The results show that CNT webs can enhance the transverse electrical conductivities of the CFRP by 231%−519% in a current range of 50–150 mA, when compared to the base-CFRP. Also, the surface temperature of CNT webs decorated CFRP can be improved by 20.5–32.3 °C within 3 min showing a self-heating rate of 6.8–10.8 °C/min just with an applied voltage of 20–30 V, increased by 152%−177% when compared to the base-CFRP (2.7–3.9 °C/min). Also, deicing can be finished within 4–10 min with a voltage of 18 V and an input power of 246 W/m². Moreover, the electrothermal processes nearly have no negative effect on the mechanical properties of the CFRP. The relatively low input power and short response time for deicing make the CNT webs decorated CFRP may be a potential new generation for aeronautical deicing structure.     

钢筋混凝土柱在随机荷载作用下的可靠性分析

本文利用可靠度理论的概率公式，并在结构失效概率计算技术的基础上，探讨了承受多种连续可变作用荷载过程的钢筋混凝土柱失效概率的计算技术，其具体方法是采用分段连续线性化极限状态方程，对非线性问题进行简化，这种方法可减少砼结构非线性分析的计算工作。对偏心受压的钢筋砼柱进行实例典型分析表明，采用线性化和高斯过程，得出的远交率的简单计算方法是可行的，并显示了作用荷载及其效应和结构抗力的随机性质。     

按钢筋混凝土框架结构的破坏状态诊断材料损伤参数

本文假定钢筋混凝土框架结构在破坏过程中混凝土材料遵循单轴受力的Mazars损伤本构模型规律，引入适当的反演目标函数，具体运用分数法和本文提出的变量转换搜索区间递减法对处于丰坏状态的钢筋混凝土框架结构的混凝土材料的一个或多个损伤参数进行反演分析获得成功，从而为定量地分析结构中材料的损伤提供了有效的途径。     

预应力混凝土梁剥落试验及分析

通过模拟不同的预应力束道上浮弯曲半径，进行了6片试验梁的剥落应力试验。分析得出了影响剥落应力的主要因素有：预应力筋张拉力、束道弯曲半径、束道中心线上下部分的结构刚度等。试验结果表明，试验梁剥落破坏曲线基本上沿波纹管中心线断面破坏。     

岩体和混凝土长期峰值强度短期试验方法的研究

本文采用自行设计的短期试验方法，对13根钢筋混凝土梁进行了长期峰值强度破坏试验，探讨了构件的极限强度与长期峰值强度之间的机理关系。     

VXI总线外场级加固型机箱的设计

在普通型主机箱的基础上，深入研究了vxI总线外场级加固型机箱的设计技术。从主要技术指标、设计和关键技术等方面，对机箱电源、总线母板、冷却系统、机械结构和电磁兼容性进行了完善和加强。有关环境试验结果表明，所研制的加固型机箱符合国军标的规定。     

Optimum alternate material selection methodology for an aircraft skin

Weight penalty has been a challenge for design engineers of aerospace vehicles. Today’s high-efficiency combat aircraft undergoes intense stress and strain during flying missions, which require stronger and stiffer materials to retain structural integrity. Though metallic materials have been successfully used for the construction of aircraft structures and components, metals still have a low strength-to-weight ratio. This paper aims to develop an alternate optimised material selection methodolog...