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1.
讨论了各向异性多层圆柱壳与极角无关的应力和变形分析方法,并导出了挠度的常微分方程,给出了应力和位移的分析解和缠绕式纤维增强及层圆柱壳的相应计算公式。  相似文献   

2.
从平衡,几何和理三类方程出发,推导了圆柱坐标系下各向异性扁壳的基本微分方程,并由此求圆柱型正交各向异性及各向同性扁壳的基本微分方程。  相似文献   

3.
从平衡、几何和理三类方程出发,推导了圆柱坐标系下各向异性扁壳的基本微分方程,并由此求得圆柱型正交各向异性及各向同性扁壳的基本微分方程  相似文献   

4.
在Timoshenko-Mindlin假设和Donnell型板壳理论基础上研究了层合非圆截面柱壳的非线性振动,得出了考虑剪切变形和面内转动惯量影响的层合非圆截面柱壳的一般非线性运动控制方程。对两端夹支椭圆截面柱壳,假设其振动形式解,用迦辽金法得到一组关于时间函数的非线性微分方程,以谐波平衡法求解,给出了数据计算结果,并就圆柱壳结果和已有文献作了比较。  相似文献   

5.
研究了无旋、无粘、可压缩流体中多层圆柱壳的自由振动问题。壳体的运动方程考虑了流体动压力的作用,流场用波动方程描述,通过采用合适的位移函数和速度势函数,使耦合问题的基本方程得到简化并进行数值求解,求得了几种不同参数的多层圆柱壳在流体中的频率特性。  相似文献   

6.
具脱层复合材料层合圆柱壳的屈曲分析   总被引:1,自引:0,他引:1  
研究了具有环向贯穿脱层圆柱壳的屈曲问题.首先基于Donnell薄壳理论和初始后屈曲理论的相邻平衡准则,建立了复合材料脱层圆柱壳的屈曲微分方程以及相应的边界条件、位移连续条件和力平衡条件.然后采用分离变量法对方程求解,讨论了脱层大小、深度、位置以及复合材料纤维铺层方向对脱层圆柱壳屈曲载荷的影响.结果表明:脱层长度越大、越靠近壳的外表和壳的轴向中心,结构的屈曲载荷越低;另外,对复合材料脱层壳而言,纤维铺层方向对结构屈曲载荷的影响也较大.  相似文献   

7.
脱层是复合材料最常见的损伤之一,它将导致结构提前失效.本文应用模态分析法研究了具环向贯穿脱层圆柱壳的轴对称屈曲问题.基于线弹性理论,建立了正交铺设脱层圆柱壳的轴对称屈曲微分方程、边界条件、位移连续务件、弯矩与剪力的平衡条件及相容条件.对方程进行求解,得到了脱层长度和深度对屈曲载荷的影响,并通过算例与已有文献进行了比较.  相似文献   

8.
水下爆炸冲击波作用下多层圆柱壳的动响应   总被引:3,自引:0,他引:3  
研究了无限域流场中球形药包爆炸时两端简支多层圆柱壳在水下爆炸冲击波作用下的动响应。由于假定流场是无旋、无粘和不可压缩的,故可用Laplace方程加以描述;而在圆柱壳的运动方程中考虑了流体动压力和冲击波压力的共同作用。利用Galerkin方法对耦合方程进行简化并数值求解,得到了多层圆柱壳在水下爆炸冲击波作用下的尖特性。  相似文献   

9.
为分析不同边界条件下旋转薄壁圆柱壳的振动特性,基于Love壳体理论,利用Hamilton原理建立了旋转薄壁圆柱壳的振动微分方程。并采用Galerkin方法对系统进行离散,将系统简化为常微分方程系统。引入振型函数,分别分析了简支-简支、固支-简支、自由-简支、固支-固支等几种不同边界条件下旋转薄壁圆柱壳的内力和固有频率特性。分析结果表明:薄壁圆柱壳的薄膜内力远大于弯曲内力;几何参数、边界条件、转速等参数对旋转薄壁圆柱壳的固有频率有重要影响。  相似文献   

10.
复合材料层合圆柱壳的径向脉冲屈曲   总被引:2,自引:0,他引:2  
针对无限长复合材料导合圆柱柱壳或圆环受均匀性向脉冲冲击作用下的动力屈曲,采用Lagrange方程导出包含横向剪为形和转动惯量的屈曲控制方程,由四阶Runge-Kutta方法所得的数值结果,寻找占优屈曲模态数及对应于允许初缺陷放大值时的临界冲击速度,通过算列,讨论了横向剪切变形,转动惯量,铺层角度等因素对角铺设层圆柱壳动力工的影响。  相似文献   

11.
Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.  相似文献   

12.
何延凌 《科技信息》2008,(4):258-258
Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women's language from these perspectives: pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women's language, more attention should be paid to language use in social context. What's more, the linguistic phenomena in a speaking community can be understood more thoroughly.  相似文献   

13.
The discovery of the prolific Ordovician Red River reservoirs in 1995 in southeastern Saskatchewan was the catalyst for extensive exploration activity which resulted in the discovery of more than 15 new Red River pools. The best yields of Red River production to date have been from dolomite reservoirs. Understanding the processes of dolomitization is, therefore, crucial for the prediction of the connectivity, spatial distribution and heterogeneity of dolomite reservoirs.The Red River reservoirs in the Midale area consist of 3~4 thin dolomitized zones, with a total thickness of about 20 m, which occur at the top of the Yeoman Formation. Two types of replacement dolomite were recognized in the Red River reservoir: dolomitized burrow infills and dolomitized host matrix. The spatial distribution of dolomite suggests that burrowing organisms played an important role in facilitating the fluid flow in the backfilled sediments. This resulted in penecontemporaneous dolomitization of burrow infills by normal seawater. The dolomite in the host matrix is interpreted as having occurred at shallow burial by evaporitic seawater during precipitation of Lake Almar anhydrite that immediately overlies the Yeoman Formation. However, the low δ18O values of dolomited burrow infills (-5.9‰~ -7.8‰, PDB) and matrix dolomites (-6.6‰~ -8.1‰, avg. -7.4‰ PDB) compared to the estimated values for the late Ordovician marine dolomite could be attributed to modification and alteration of dolomite at higher temperatures during deeper burial, which could also be responsible for its 87Sr/86Sr ratios (0.7084~0.7088) that are higher than suggested for the late Ordovician seawaters (0.7078~0.7080). The trace amounts of saddle dolomite cement in the Red River carbonates are probably related to "cannibalization" of earlier replacement dolomite during the chemical compaction.  相似文献   

14.
理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。  相似文献   

15.
As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.  相似文献   

16.
AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…  相似文献   

17.
There are numerous geometric objects stored in the spatial databases. An importance function in a spatial database is that users can browse the geometric objects as a map efficiently. Thus the spatial database should display the geometric objects users concern about swiftly onto the display window. This process includes two operations:retrieve data from database and then draw them onto screen. Accordingly, to improve the efficiency, we should try to reduce time of both retrieving object and displaying them. The former can be achieved with the aid of spatial index such as R-tree, the latter require to simplify the objects. Simplification means that objects are shown with sufficient but not with unnecessary detail which depend on the scale of browse. So the major problem is how to retrieve data at different detail level efficiently. This paper introduces the implementation of a multi-scale index in the spatial database SISP (Spatial Information Shared Platform) which is generalized from R-tree. The difference between the generalization and the R-tree lies on two facets: One is that every node and geometric object in the generalization is assigned with a importance value which denote the importance of them, and every vertex in the objects are assigned with a importance value,too. The importance value can be use to decide which data should be retrieve from disk in a query. The other difference is that geometric objects in the generalization are divided into one or more sub-blocks, and vertexes are total ordered by their importance value. With the help of the generalized R-tree, one can easily retrieve data at different detail levels.Some experiments are performed on real-life data to evaluate the performance of solutions that separately use normal spatial index and multi-scale spatial index. The results show that the solution using multi-scale index in SISP is satisfying.  相似文献   

18.
In the 19th century the society was controlled by men, and women were just appendants of them, they had not any rights and freedom. But Jane was an exception, she showed some characteristics of early feminist. Jane showed her characteristics of feminism in three aspects: rebellion, equality, and independence. These characteristics were helpful to her success, and feminism is the only way out for women of that time.  相似文献   

19.
正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-  相似文献   

20.
We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-  相似文献   

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