排序方式: 共有27条查询结果,搜索用时 15 毫秒
11.
水平井中钻柱屈曲的非线性有限元分析 总被引:1,自引:0,他引:1
建立了直井中钻柱屈曲的平衡方程及对应的泛函表达式,使用有限元法对不同约束下水平井中钻柱从稳定到非线性屈曲的整个过程进行了分析。力学模型中考虑了重力和扭矩对屈曲的影响。分析结果表明:钻柱的屈曲是一个从局部屈曲到总体屈曲的过程,屈曲段的井壁约束力、钻柱弯矩和屈曲位移呈周期性变化;重力在水平井中对屈曲有较强的抑制作用;边界约束对屈曲的影响不可忽略;扭矩对屈曲的影响很小,可以忽略。 相似文献
12.
13.
Yanyan Wang Gongbiao XinWei Li Wei WangChongyun Wang Jie ZhengXingguo Li 《International Journal of Hydrogen Energy》2014
Mg–Y thin films capped with Pd have been prepared by direct current magnetron co-sputtering system. It is found that Mg alloyed with Y in film state forms ultrafine nanocrystalline intermetallic compounds. The structure together with the catalytic effect of Y gives rise to a high electrochemical hydrogen storage capacities and superior activation properties. It is worthy to note that Mg78Y22 film achieves a high discharge capacity of 1590 mAh g−1 without requiring activation process. Moreover, Mg alloyed with Y effectively improves the cyclic stability of Mg-based films ascribing to the anti-corrosion role of Y. For Mg37Y63 film, more than 92% of the maximum discharge capacity can be maintained after 100 charge–discharge cycles. 相似文献
14.
He ZuYun Guo Zheng Zhong Xiao Chen XiaoFei Xue JianMing Wang XinWei Chen Yan 《中国科学:技术科学(英文版)》2021,64(3):611-619
Due to the extremely large surface to bulk ratio, the properties of single layer(SL) MoS_2 are largely determined by its interaction with environment. One critical interaction process that has been intensively investigated is the oxidation process of MoS_2.Despite numerous previous explorations, the detailed mechanism regarding how MoS_2 reacts with oxygen is still not well understood. In this work, we systematically investigate the impact of intrinsic and pre-created defects on the oxidation process of SL MoS_2. For pristine SL MoS_2, the oxidation is found to initiate near point defects and grain boundaries, leading to the formation of triangle pits in the basal plane and cracks near the grain boundaries. The pre-created defects introduced by ion irradiation are found to serve as the oxidation center, resulting in a more uniform oxidation process. The oxidation is found to introduce p-type doping in the SL MoS_2, leading to the blue shift of Raman and photoluminescence(PL) spectra. The shift is found to be more for the region near the grain boundary and for the samples with more pre-created defects. Our results suggest that the presence of defects can strongly promote the oxidation reaction of SL MoS_2 in ambient condition, which significantly affects the stability and functionality of materials. 相似文献
15.
人工神经网络技术在超临界流体密度预测中的应用 总被引:4,自引:3,他引:4
超临界流体的性质常与其密度相关。因此,如何精确计算超临界流体在不同操作条件下的密度值,对于超临界流体过程的研究和设计均十分重要。本文尝试采用人工神经网络技术来预测计算超临界流体的密度。网络结构为3层BP网,经优化中间隐藏层单元数为6。通过训练和学习,在压力6MPa-8MPa、温度300K-320K范围内,神经网络预测的密度值,其相对误差<0.35%。比P-B状态方程计算的结果精确。 相似文献
16.
有机蒸气分离膜的应用 总被引:1,自引:0,他引:1
介绍了有机蒸气分离膜的分离原理,并分别介绍了有机蒸气分离膜在石油化工和聚氯乙烯行业中的应用. 相似文献
17.
为了准确而可靠地评估货车车轮的结构强度,建立车轮的有限元模型,用人工划分和自动划分相结合的方法将车轮划分成六面体单元模型,对模型施加约束和载荷,求解出von Mises应力和最大剪应力,分别用von Mises准则与Tresca准则对车轮进行应力分析,有效地确定车轮结构危险点,并对计算结果的数值稳定性进行分析。对车轮静态弯曲实验的测点进行实验应力分析(包括von Mises应力和最大剪应力),验证有限元分析结果,并分析实验误差的产生原因。结果表明,采用六面体单元的线性有限元分析方法,能准确确定车轮结构危险点,具有很好的数值稳定性,适用于对货车车轮进行结构强度分析。 相似文献
18.
周边夹持大应变金属薄膜变形特性有限元分析 总被引:3,自引:0,他引:3
受侧向载荷作用的金属薄膜可作为一种功能元件用于防止装置超压或实现某些特定的工艺操作,在许多行业被大量使用。几何和材料非线性的特点使得解析计算非常困难,目前其设计和制造主要依赖于实验。文中采用MITC4(mixed interpolation of tensorial components)壳元基于T.L.(Totoal Iagrange)列式,对普通和开有透缝的二种结构形式的金属薄膜进行有限应变弹塑性有限元分析。通过与实验结果的比较,得出如下的结论,①普通膜的高应力应变区位于极顶附近约1/3口径的区域,应力梯度自周边向内不断减弱。②极顶挠曲高度随加载呈弱“S”形的规律变化。③随加载,横向塑性应变的变化过程可以划分为缓慢增加段、过渡段和快速增加段3个阶段,阶段的2个分界点为pa/so≈530MPa和880MPa。④透缝膜高应力应变区位于内圈终止小孔孔桥间的边缘局部区域。⑤存在一个重要的数群pa/(s0b),不同d时最大等效应力相对于该数群具有十分相近的变化规律。 相似文献
19.
20.
分析了造成灯芯绒织物染色织物摩擦牢度差的原因,采用无醛固色剂Tinokin VG对硫化、活性染色灯芯绒织物进行处理,发现处理后其干摩擦牢度可提高2.5级,湿摩擦牢度可提高1.5级。如经焙烘固化,其效果更佳。染物处理后不会发生色变现象。 相似文献