热处理对锰硼白口铁机械性能与显微组织的影响

研究了淬火、回火温度、冷却介质对锰硼白口铁机械性能及显微组织的影响。结果表明:淬火硬度随淬火温度提高出现峰值,峰值位置随淬火冷却速度增加向温度低的方向移动;回火硬度随回火温度升高在250℃出现峰值,回火温度高于480℃后硬度显著降低;残留奥氏体随回火温度升高而减少,430℃回火残留奥氏体基本消失,转变产物为贝氏体;淬火回火提高强韧性。     

公路双连拱隧道结构设置研究

应用有限单元法,讨论了设置双连拱结构所要求的两洞间距上限值;并研究了不同围岩情况下双连拱隧道的力学特性,得出了一些对工程设计有用的结论。     

等离子喷涂WC-17Co纳米涂层形成及强韧化机理

用等离子喷涂的方法制备WC-17Co纳米涂层和普通涂层,以研究纳米涂层组织的形成机理、力学性能及强韧化机理.研究表明,纳米涂层中存在典型的纳米结构.在纳米WC-17Co喷涂粉末中,WC颗粒上弥散地分布的2~5 nm的亚微粒作为结晶晶核,有利于纳米结构涂层的形成.纳米涂层的硬度、弹性摸量、断裂韧性和结合强度都明显高于普通涂层,细晶强化是其主要强化机制.     

等离子喷涂陶瓷涂层性能的研究

金属基底上喷涂陶瓷涂层使表面具有耐磨、耐磨蚀、耐高温等特点,用运等离子涂技术在４５号钢表面喷涂Ａｌ２Ｏ３、Ａｌ２Ｏ３－３％、ＴｉＯ２、ＴｉＯ２、ＺｒＯ２－８％Ｙ２Ｏ３等四种陶瓷涂层,部分采用Ｎｉ包Ａｌ为打底层,检测陶瓷涂层的硬度,耐磨性及结合力等力学性能,并进行相和扫描电镜观察,四种陶瓷涂层的表面硬度达到７０－９０ＨＲ１５Ｎ;有打底层的陶瓷涂层的硬度稍大于无底层的涂层硬度;Ａｌ２Ｏ３－３％ＴｉＯ２     

Mechanical model and mechanical property analysis of fibre-reinforced hybrid composite pipes

Compared to conventional fibre-reinforced composite pipes, fibre-reinforced hybrid composite pipes are more complex and are characterised by the use of hybrid fibres, hybrid matrices, and multiple fibre winding angles. In this study, based on the mechanical model of conventional fibre-reinforced composite pipes, the cross-section division method, the radial pressure on the adjacent layer by spiral wound rope structures, and the calculation method of axial force in each layer were improved. Furthermore, the von Mises stresses in each layer were calculated to discriminate the failure to establish a mechanical model of fibre-reinforced hybrid composite pipes with any number of reinforced layers under axial tension, internal pressure, and external pressure. Experimental data and the finite element method (FEM) were used to verify the reliability of the established model, with the axial tensile mechanical properties analysed based on the established model. The results showed that the large-angle fibres no longer withstood the axial tensile load when the winding angle of the large-angle fibres was greater than 45°. The matrices yielding was much earlier than the fibre breakage. The matrices hybrid methods have a large influence on the axial tensile properties of fibre-reinforced hybrid composite pipes, and improving the material properties of the inner and outer liners can significantly improve the axial tensile properties of fibre-reinforced hybrid composite pipes.     

海底掩埋目标的散射特性分析

在对不同掠射角条件下掩埋目标的散射特性进行分析的基础上,认为低频、宽带、窄波束在小掠射角的情况下是适合掩埋目标探测和识别的,并对掩埋目标探测和识别声纳设计提出了建议。     

Synthesis and Characterization of Polyurethane and Epoxy Resin Interpenetrating Polymer Network

A series of Polyurethane (PU)/bisphenol A based Epoxy Resin (EP) Interpenetrating Polymer Networks(IPN) were synthesized and characterized by SEM, DSC, TGA and DMTA. It was found that IPN shows the best compatibility and damping properties when the ratio of PU/EP is 80 to 20. The results show that chain-extender and higher molecular weight of PPG are able to improve the properties of compatibility, damping and thermal properties.     

动态载荷下轮胎侧偏特性的理论及试验研究

提出了在动载和时变印迹长度下轮胎的接触历程概念,导出了计算动载时轮胎接地印迹内各点接触历程的入迹方程,阐明轮胎动载侧偏力学特性建模机理,克服了动载侧偏特性理论建模的一个基本障碍,建立了考虑胎体平移弹性小幅动载时的理论模型,并提出了轮胎动载侧偏特性的半经验模型,进行了相应的试验研究,给出了试验结果与模型计算结果的比较。     

薄层环氧桥面铺装材料低温性能研究

采用三点弯曲断裂、疲劳试验,室内加速加载磨耗试验和温缩系数试验研究薄层环氧铺装材料的低温性能。试验结果表明在-10℃时其弯拉断裂应变大于4 000μm/m。当加载的疲劳应变大于1 000μm/m时,仍表现出很好的低温抗疲劳性能。加速加载磨耗次数达到6万次后表面构造浓度大于1 mm,温缩系数为5.88×10-5/℃,水泥混凝土板表面浮浆清除和糙面处理可有效地增加界面黏结强度,以抵抗低温收缩应力,避免层间黏结不足而产生的脱层问题。     

Influence of Ca Element on Microstructure and Mechanical Properties of AZ61-1.2Y

The effects of Ca element on the microstructure and mechanical properties of AZ61-1.2Y alloy were investigated by microstructure observation, tensile tests and fracture analysis. The results show that, with the addition of Ca element, the microstructure of AZ61-1.2Y was obviously refined, high melting point Al2Ca intermetallic compound formed, and β-Mg17Al12 phase disappeared. With 1.0% Ca addition, the values of tensile strength at 25, 150 and 175 ℃ reached their maxima simultaneously, 225, 182, and 175 MP...