共查询到20条相似文献，搜索用时 15 毫秒
1.
Since the jets and detonation gaseous products are separated by sharp interfaces,the traditional smoothed particle hydrodynamics (SPH) method is difficult to avoid the computational instability at interfaces.The multi-phase SPH (MSPH) method was applied to improving the stability,which smoothes the particle density and makes pressure continuous at interfaces.Numerical examples of jet forming process were used to test capability of the MSPH method.The results show that the method remains algorithm stability for large density gradient between the jets and gaseous products and has potential application to both the explosion and the jet problems.The effect of initiation ways of the shaped charge was discussed as well. 相似文献
2.
夏南 《上海大学学报(英文版)》1999,3(1):4-6
The stability condition for compressible and incompressible swirling flow is discussed and compared. It is found that Eckhoff and Storesletten's necessary condition for stability of inviscid compressible swirling flow seems incorrect. 相似文献
3.
Xia Nan 《上海大学学报(英文版)》1999,(1)
１ Ｉｎｔｒｏｄｕｃｔｉｏｎ Ｔｈｅｐｒｏｂｌｅｍｏｎｔｈｅｓｔａｂｉｌｉｔｙｏｆｉｎｖｉｓｃｉｄｉｎｃｏｍｐｒｅｓｓｉｂｌｅｓｗｉｒｌｉｎｇｆｌｏｗｈａｓｂｅｅｎｓｔｕｄｉｅｄｂｙｍａｎｙａｕｔｈｏｒｓ．Ｒａｙｌｅｉｇｈ［１］ｉｎｖｅｓｔｉｇａｔｅｄｔｈｅｆｌｏｗｗｉｔｈｃｏｎｓｔａｎｔａｘｉａｌｖｅｌｏｃｉｔｙ,ｉ．ｅ．Ｕ′＝ｄＵｄｒ＝０ａｎｄｆｉｒｓｔｇｏｔａｓｕｆｆｉｃｉｅｎｔａｎｄｎｅｃｅｓｓａｒｙｃｏｎｄｉｔｉｏｎｏｆｓｔａｂｉｌｉｔｙｆｏｒａｘｉｓｙｍｍｅｔｒｉｃｄｉｓｔｕｒ… 相似文献
4.
Since the jets and detonation gaseous products are separated by sharp interfaces, the traditional smoothed particle hydrodynamics (SPH) method is difficult to avoid the computational instability at interfaces. The multi-phase SPH (MSPH) method was applied to improving the stabil-ity, which smoothes the particle density and makes pressure continuous at interfaces. Numericalexamples of jet forming process were used to test capability of the MSPH method. The results show that the method remains algorithm stability for large density gradient between the jets and gaseous products and has potential application to both the explosion and the jet problems. The effect of initiation ways of the shaped charge was discussed as well. 相似文献
5.
1 Introduction Cavitation phenomenon,i.e.,the sudden forma-tion of void , has been observed in a wide variety ofmetals and alloys[1].It has also been observed in rub-ber[2]and elastomers[3].As cavitation phenomenon re-lates to the mechanism of local failu… 相似文献
6.
不可压各向异性超弹性材料中的空穴生成 总被引：3，自引：0，他引：3
The cavitation problem in a solid sphere composed of an incompressible anisotropic hyper-elastic material under a univroms radial tensile dead load was examined.A new analytical solution was obtained.The stress contruibutions were given and the jumping and concentration of stresses were discussed.The stability of solutions and the effect of the degree of ainsotropy of the material were analyzed. 相似文献
7.
葛瑛 《杨凌职业技术学院学报》2008,7(1):51-54
水泥土搅拌桩是利用水泥（或石灰）等材料作为固化剂,通过特制的搅拌机械在地基中将软士和固化剂强制搅拌,使软士硬结成具有整体性、水稳性和一定强度的水泥加固士,从而提高地基士强度,增大变形模量。此方法适用于软基处理,效果显著。使用水泥士搅拌法加固地基也有其局限性,这点更应该引起设计单位的重视。当采用水泥士搅拌法用于处理无类似工程经验的地区或工程时,必须有针对性的进行地质勘探补探工作,按规范通过设计前期的现场试验确定其适用性。 相似文献
8.
宋玉娥 《北京工业职业技术学院学报》2008,7(4):6-10
研究了各向同性不可压超弹性材料球体在表面均匀拉伸死载荷作用下的空穴分岔问题,得到了描述球体内部的空穴生成和增长的空穴分岔方程,证明了空穴分岔方程的平凡解支上存在唯一的分岔点,并给出了分岔的辨别条件;利用奇点理论给出了空穴分岔方程在分岔点的等价正规形,并利用最小势能原理讨论了空穴分岔方程的稳定性。 相似文献
9.
Mechanism of Breakdown in Laminar-Turbulent Transition of Incompressible Boundary Layer on a Flat Plate 总被引：2，自引：0，他引：2
Temporal mode direct numerical simulation was done for the process of laminar-turbulent transition in an incompressible boundary layer on a flat plate. The analysis of the results showed that during the breakdown process of laminar-turbulent transition, the modification of the mean flow profile by the disturbances led to a remarkable change in its stability characteristics, manifested in the significant enlargement of the linear unstable zone and the maximum amplification rate, and led to that many more disturbances were excited and enhanced rapidly, correspondingly the turbulent energy also increased rapidly, and the mean flow profiles evolved swiftly from laminar to turbulent. It was also found that if the oblique waves in the initial disturbances did not form symmetrical pairs, the subsequent span-wise mean velocities would, in general, be nonzero due to nonlinear interaction, which would have a great effect on the stability characteristics and also implied that the turbulence obtained by direct numerical simulation might not be fully a random process. 相似文献
10.
A numerical simulation of the interaction between laminar flow with low Reynolds number and a highly flexible elastic sheet is presented. The mathematical model for the simulation includes a three-dimensional finitevolume based fluid solver for incompressible viscous flow and a combined finite-discrete element method for the three-dimensional deformation of solid. An immersed boundary method is used to couple the simulation of fluid and solid. It is implemented through a set of immersed boundary points scattered on the solid surface. These points provide a deformable solid wall boundary for the fluid by adding body force to Navier-Stokes equations. The force from the fluid is also obtained for each point and then applied on the boundary nodes of the solid. The vortex-induced vibration of the highly flexible elastic sheet is simulated with the established mathematical model. The simulated results for both swing pattern and oscillation frequency of the elastic sheet in low Reynolds number flow agree well with experimental data. 相似文献
11.
煤矿采空区是影响高速公路路基和构筑物稳定的重大安全隐患。运用概率积分法的理论和方法计算了青岛-兰州高速公路邯郸-涉县段北八特采空区地表沉陷量。计算结果表明,不论是煤层回采后的最大沉陷量、水平位移、水平变形、斜率和曲率等各项变形指标,还是现今各项剩余变形指标都超过了我国高速公路路基变形容许值,特别是K123＋350～K123＋900段以及K124＋500～K124＋900段地表剩余变形量大,对拟建高速路基和构筑物影响严重。 相似文献
12.
秦训鹏 《黄冈职业技术学院学报》2009,11(4):10-13
可压缩烧结材料变形时体积发生变化,塑性理论只能建立在质量不变条件之上,金属塑性力学理论范畴的初等解析法、滑移线法、有限元法以及上限分析法为求解不同状况下的可压缩烧结材料塑性变形问题提供了有效的途径。 相似文献
13.
通过对某桥台高路堤工程勘察及历时一年的原位动态变形监测，重点阐述了粘性土直接修筑高路堤结构的变形特征、历时规律和变形稳定性，提出粘性土高路堤工后3年自身变形尚未完全稳定的结论。 相似文献
14.
苗德华 《天津工程师范学院学报》2011,21(3)
应用疲劳试验机对退火后15号和45号碳钢及其各自3种塑性变形材料进行了回转弯曲及扭转疲劳实验,讨论了在相同塑性变量的条件下,两种钢材的扭转疲劳极限与回转弯曲疲劳极限之间的关系。实验结果表明：15号和45号钢的扭转与弯曲疲劳极限的比,分别为0．53～0．57和0．57～0．58,即塑性变量相同的情况下,含碳量高的材料其疲劳极限比也较高;相同含碳量的情况下,塑性变形量较小时其疲劳极限比较低。 相似文献
15.
In order to study the effect of seismic permanent deformation on the safety and stability of earth-rock dam, the permanent deformation is considered as the non-design permanent load, and the stress-strain hysteresis curve is also considered when the earth is under cyclic load. The research work can make the calculation results of plastic collapse more accurate by including the effect of the post-earthquake degree of plastic deformation on the stability of the earth-rock dam, and the dam safety factor decreases from 2.50 to 1.90 after the magnitude-8 earthquake. Moreover, the research work will also improve the design of the earth-rock dam under abnormal operating conditions. 相似文献
16.
通过有限元模拟及算例验证,分析了高层建筑考虑施工过程中混凝土材料徐变对结构竖向变形的影响。分析表明,混凝土的徐变变形作用对柱的轴力影响不大,但对柱端弯矩影响较大;考虑徐变变形的柱端弯矩计算结果较没有考虑徐变变形的情况有显著减小。在考虑徐变影响的情况下,各层位移均有所增加,且两者的最大差值相差较大,很可能会影响结构的正常使用,在设计过程中不应忽视。该研究结果可为考虑高层建筑结构在施工过程中材料的徐变性能对结构内力的影响提供理论依据及分析方法。 相似文献
17.
黄伟达 《福建工程学院学报》2012,10(6):567-570
在高陡填方区采用土工格栅加筋土挡墙,容易产生较大变形,且至变形稳定持续时间长。文章以某填方边坡为例,对无面板式加筋土挡墙的变形性状进行分析,分析结果表明,无面板式高陡加筋土挡墙的大变形,主要是地质条件、填料及土工格栅材料、施工条件、面板等综合影响。基此,提出了防患加筋土挡墙变形的相应建议。 相似文献
18.
Journal of Science Education and Technology - This article describes how the world-wide web is currently used by a mathematics educator. The author describes a multi-phase teaching experiment... 相似文献
19.
ＩＮＴＲＯＤＵＣＴＩＯＮＩｔｈａｓｂｅｅｎｒｅｃｏｇｎｉｚｅｄｔｈａｔｌｏｎｇ ｓｐａｎｂｒｉｄｇ ｅｓ ,ｃａｂｌｅ ｓｕｐｐｏｒｔｅｄｂｒｉｄｇｅｓｉｎｐａｒｔｉｃｕｌａｒ,ａｒｅｓｕｂｊｅｃｔｔｏｔｈｅｄｙｎａｍｉｃｗｉｎｄａｃｔｉｏｎ .Ｔｈｅａｅｒｏｄｙ ｎａｍｉｃｓｔａｂｉｌｉｔｙ (ｆｌｕｔｔｅｒ)ｏｆｓｕｓｐｅｎｓｉｏｎｂｒｉｄｇｅｓｄｕｒｉｎｇｅｒｅｃｔｉｏｎｉｓａｓｕｂｊｅｃｔｏｆｍａｊｏｒｃｏｎｃｅｒｎｆｏｒｒｅｓｅａｒｃｈｅｒｓａｎｄｅｎｇｉｎｅｅｒｓ .Ａｌｔｈｏｕｇｈｔｈｅｐｅｒｉ… 相似文献
20.
PdSi合金与金属Cr膜压痕蠕变研究 总被引：1，自引：0，他引：1
蠕变变形是薄膜和微机电系统应用中普遍存在的可靠性问题,因此有必要考察薄膜材料和小体积材料的蠕变行为。采用深度敏感纳米压痕方法对单晶PdSi合金和金属Ni基体上沉积Cr膜进行了室温压痕蠕变研究,分析蠕变应力指数和蠕变机制。结果表明:随硬度减小,蠕变深度增大,在不同应变率下计算得出应力指数PdSi合金在26.3~47.1之间;金属Cr膜在4.1~22.5之间。蠕变变形机制是位错的滑动和攀移,在高应变率下保载阶段瞬时影响更显著。 相似文献