结构设计中的混沌优化方法及其改进

在变尺度混沌优化方法研究中．结合结构优化问题的特点,提出了一种改进的混沌优化求解算法,用来解决带有多种约束条件的结构优化设计问题。在有限元分析和优化设计软件JEFIX中实现了上述算法．并通过数值算例讨论了变尺度混沌优化方法在结构优化中的可行性及存在的问题,得到了一些重要结论。     

中心力场中散射角的简洁推导

本文从牛顿方程及角动量守恒定律出发 ,利用矢量函数的微积分运算技巧简捷地推导出中心力场中散射角 φ,避免了经典教科书中从轨道方程出发推导出 φ的繁琐性 ,不仅计算简洁 ,而且物理过程明确 .     

非牛顿流体内流传热研究

在本文中,研究了注入轴对称模腔非牛顿流体非定常流动.本文的第二部份研究了上随体Maxwell流体管内热流动.对于注入模腔流动.其本构方程采用幂律流体模型方程.为了避免在表现粘度中温度关系引起的非线性.引进了一特征粘度的概念.描述本力学过程的基本方程是,本构方程、定常状态的运动方程、非定常能量方程及连续方程.该方程组在空间是二维问题,在数学上是三维问题.采用分裂差分格式求得本方程组的数值解答.分裂法曾成功应用于求解牛顿流体问题.在本文中,首次将分裂法成功地应用解决非牛顿流体流动问题.对于圆管内热流,给出了差分格式,使基本方程组化为一个三对角方程组.其结果,给出了不同时刻的模腔内二维温度分布.     

液相色谱梯度淋洗过程中溶剂的分布规律

在液相色谱梯度淋洗过程中,由于柱外过程和流动相在柱内的输运过程中的延迟作用和扩散的影响,使得溶剂浓度梯度变化时,在柱内特定位置的浓度随时间的变化符合相应的分布规律.本文从理论和实验两个方面对这一规律加以探讨,并讨论了仪器条件对该分布规律的影响.     

Applications of wavelet galerkin fem to bending of beam and plate structures

I.IntroductionItilasbeenl'oundthatthewavelettheoryisapowerfLllmathematicaltooldevelopedillrecentyears.Asanewmathematicaltool,ithasbeenextensivelyappliedintheanalysisofsignalprocess,parttenrecognition,functionapproximation,andsolvingdifferentialequation(s),etc..Sinceasmallsignalinasighalprocesscanbecapturedbythewavelettheory,itsapplicationshavebeenpaidmuchattentionbothintheoryandinengneeringf'~'].Recently,thewavelettheory11asbeengeneralizedtofindanumericalsolutionofadifferentialequation.Forex…     

HIGH RESOLUTION SCB SCHEME FOR HYPERBOLIC SYSTEMS OF 2-D CONSERVATION LAWS

1.IntroductionConsidernumericalsolutionsoftheinitialvalueproblemforhyperbolicconservationlawsinonedimensionwhereu~(.ul,u2,...,"m)"andf(u)~(fi(u),fZ(u),',fm(u))".Andconservationlawsintwodimensionswhereu~(ul,u25...,"m)',f(u)~(fi(u),fZ(u),'?fm(u))',andg(u)~(gi(u),gZ(M),',gm(U))".FOrthescalarconservationlawsinonedimension,theTVDconceptbyA.Ha.te.[3]iswidelyacceptedtodesignthenumericalschemesfortheoreticalpurposesandpracticalapplications.Thetotalvariationofagridfunction{uj}denotedbyTV(u)…     

非牛顿流体在环管内的不定常旋转流

本文研究幂律非牛顿流体在环管内的不定常旋转流。该方程是一非线性方程,在部分因子的稳态近似假设之下,方程被线性化,用Laplace积分变换法我们获得了问题的解。文中给出了几组解曲线,它反映了角向速度的时间演化规律与空间分布特征。另外我们专门研究了幂律指数对流场的影响,该参数的敏感性具有一定的数值界限。这一结果,在有关的工程设计中具有重要的意义。     

C1 Rational interpolating surface under local coordinate systems

A method of constructing rational interpolating surface under local coordinate systems is presented, which can be used to solve the large torsion problem of surfaces. This kind of surface has better approximating effect and its properties can be easily discussed, so it has practical applications not only in CAD but also infinite element analysis and other fields. An example is given in the paper.Projects Supported by the Science Fund of Education Committee.     

The generalized variational principles about blending energy form of non-linear elasticity

First of all, this paper gives Legendre transformation for the so-called partial corresponding variables of strain energy function Σ(E_ij) and complementary strain energy function Σc(S_ij) of the elastic materiel, and introduces the corresponding blending complementary strain energy function Σch_k! and blending strain energy function Σh_k!. Moreover, a series of generalized variational principles of the corresponding blending energy form of non-linear elasticity is given. As a special case, there exist corresponding results[1] in linear elasticity.     

The leakage criterions of thin-wall pressure vessels,materials of missile and spacecraft

This paper presents the development of three leadage criterions to predict fracture in thin-wall pressure vessels, materials of missile and spaceraft. Experimental results show that the criterions are successful.I. Notation P internal pressure kg/mm² - _b critical stress kg/mm² - t wall thickness mm - r internal radius mm - t _o wall thickness at crack tip mm - r _o internal radius at crack tip mm - _B yield strength kg/mm² - _H circumferential stress at the yield tange of the crack tip kg/mm² - n rate of strain gardening - 2c length of surface-crack mm - a depth of surface-crack mm - L length of testing piece mm - K, C, B, aA constant