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121.
具有初始缺陷的内胆会对复合材料气瓶的服役性能造成严重危害,本文基于响应面法,提出了一种复合材料气瓶含初始缺陷内胆屈曲的可靠性分析方法。建立了铝合金6061内胆的T700/环氧复合材料气瓶的三维有限元模型,实现了复合材料气瓶内胆的收缩屈曲分析。基于响应面方法,构造了复合材料气瓶极限状态方程,并假设结构中的随机变量服从高斯分布,开展了考虑几何尺寸和凹陷尺寸变化的气瓶结构可靠性分析,结果表明,在气瓶内胆加工过程中,直筒段厚度的离散性会严重影响气瓶结构的可靠性;直筒段半径、直筒段长度、封头段半径和封头段厚度在通用加工误差内对气瓶结构的可靠性影响较小;对本文定型气瓶,当内胆表面的凹陷半径超过10 mm,且深度超过2 mm时,气瓶结构的可靠性会严重降低。 相似文献
122.
123.
利用可调谐真空紫外同步辐射和分子束实验装置在8.0~15.5 eV的光子能量范围内,研究2-甲基-2-内烯-1-醇的光电离解离.测出母体离子和碎片离子:C_4H_8O~+、C_4H_7O~+、C_3H_5O~+、C_4H_7~+、C_4H_6~+、C_4H_5~+、C_2H_4O~+、C_2H_3O~+、C_3H_6~+、C_3H_5~+、C_3H_3~+、CH_3O~+和CHO~+的光电离效率曲线,并获得母体分子的电离能和碎片离子的实验出现势.在B3LYP/6-31+G(d,p)理论水平上,计算光电离过程中母体分子、过渡态和中间体的稳定结构.采用CCSD(T)/cc-pVTZ耦合簇方法计算零点能,得到母体电离能和碎片离子的出现势.通过实验和理论研究,提出2-甲基-2-丙烯-1-醇的光解离路径,分子内氢转移是其中大部分解离途径中的主要过程. 相似文献
124.
基于ANSYS对CFETR真空室简化模型进行了2D/3D电磁分析,得到了真空室磁场强度以及电磁力的分布。分析结果显示2D/3D真空室的磁场强度及电磁力分布基本一致,这表明了可以使用2D模型替代3D模型对未来真空室简化模型进行电磁分析。 相似文献
125.
利用非平衡格林函数与密度泛函理论相结合方法研究了电极表面具有原子级突起的铜-真空-铜隧道结的转变电压.计算结果表明,铜电极真空隧道结的转变电压主要决定于电极表面尖端铜原子4p轨道的局域态密度,因而对电极取向和表面局域原子构型非常敏感.对于电极取向沿(111)方向的铜电极真空隧道结,当电极表面原子级突起取为铜吸附原子和金字塔型铜纳米粒子两种构型时,转变电压的计算值分别约为1.40和2.40 V.当电极取向沿(100)方向时,电极表面原子级突起分别为铜吸附原子和金字塔型铜纳米粒子两种构型的铜电极真空隧道结,其转变电压的差异更为显著.具体而言,电极表面有一金字塔型铜纳米粒子的铜电极真空隧道结的转变电压值减小至1.70 V,而电极表面原子级突起为铜吸附原子的铜电极真空隧道结却因铜吸附原子4p轨道的局域态密度过于扩展,即使在偏压超过1.80 V时仍然没有出现转变电压.这些结果表明转变电压谱可用作分析金属电极真空隧道结电子输运特性的有力工具. 相似文献
126.
The paper presents an analytical solution to Lamé's problem for a hollow sphere with unknown evolving boundaries. The double-sided uniform corrosion of a linearly elastic thick-walled spherical shell under internal and external pressure is considered. It is assumed that the corrosion rates are piecewise linear functions of the maximum principal stress on the related surface, and exponentially decaying with time. The corrosion process is supposed to be divided into three successive stages: constant rate double-sided corrosive wear, a stage of corrosion accelerated on only one of the surfaces of the shell, and a double-sided mechanochemical corrosion. Closed-formed expressions for all the consecutive stages are obtained with their junction points (corresponding to stress corrosion thresholds) being taken into account. 相似文献
127.
《Wave Motion》2015
Pressure vessels usually operate under extremes of high/low temperatures and high pressures. Defect, such as crack and corrosion, can result in leakage or rupture failures, even catastrophic incidents. Guided wave-based structural health monitoring (SHM) technology is one of the most prominent options in non-destructive evaluation and testing (NDE/NDT) techniques. Propagation of guided waves in a typical pressure vessel is systematically investigated in this study for the application of guided wave-based SHM. Shape of the pressure vessel is a cylinder with two end caps. Because of geometric similarity, theory of guided wave propagation in the cylinderical structure is analyzed to study dispersive features of guided waves in the pressure vessel. Dispersion curves of three different types of guided wave modes, viz. the longitudinal, torsional and flexural modes, are calculated using theoretical method. Based on the analyses and experimental wave signals, central frequency and wave parameters of incident wave are optimized. Effect of contained liquid on propagation of guided waves, especially the L(0, 2) mode, in the pressure vessel is further investigated to minimize energy leakage of the wave to the contained liquid. The analytical method, finite element analysis (FEA) and experiments are applied to study propagation characteristics of guided waves in the pressure vessel, so as to demonstrate the feasibility of guided wave-based non-destructive evaluation and testing (NDE/NDT) for such kind of complex structures. 相似文献
128.
The surface of cyclo-olefin polymer (COP) was treated with vacuum ultraviolet (VUV) light at 172 nm wavelength to improve the wettability and adhesion properties. Through VUV treatment in air, the terminal groups of the COP surface were oxidized into oxygen functional groups, containing CO, CO, and COO components, making the COP surface hydrophilic. The extent of oxygenation was evaluated by XPS and FTIR-ATR spectra, and it was shown that the surface properties, hydrophilicity, and functionalization were dependent on both VUV irradiation distance and irradiation time, which have an effect on the concentration of oxygen functional groups. VUV-light treatment with a short irradiation distance was more effective in introducing oxygen functional groups. 相似文献
129.
A.?Giuliani P.?Lim?o-Vieira D.?Duflot A. R.?Milosavljevic B. P.?Marinkovic S. V.?Hoffmann N.?Mason J.?Delwiche M.-J.?Hubin-Franskin 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2009,51(1):97-108
The electronic spectroscopy of isolated tetrahydrofuran (THF) in the gas phase has been investigated using high-resolution
photoabsorption spectroscopy in the 5.8–10.6 eV with absolute cross-section measurements derived. In addition, an electron
energy loss spectrum was recorded at 100 eV and 10° over the 5–11.4 eV range. The He(I) photoelectron spectrum was also collected
to quantify ionisation energies in the 9–16.1 eV spectral region. These experiments are supported by the first high-level
ab initio calculations performed on the excited states of the neutral molecule and on the ground state of the positive ion.
The excellent agreement between the theoretical results and the measurements allows us to solve several discrepancies concerning
the electronic state spectroscopy of THF. The present work reconsiders the question of the lowest energy conformers of the
molecule and its population distribution at room temperature.
Electronic supplementary material Supplementary Online Material 相似文献
130.