查询词典 boundary element method

Based on the fundamental solution of plane piezoelectric problems and the basic thought of the virtual boundary element method for elasticity, this paper presents a virtual boundary element-equivalent collocation method for plane piezoelectric materials.

利用压电材料平面问题的基本解和弹性力学虚边界元方法的基本思想，提出了压电材料平面问题的虚边界元-等额配点解法。

There is no difficulty for us to solve N-K problem for submerged bodies by the coupled element method, but for wavemaking problems of the bodies piercing free surface, we get a difficult problem of line integral on the free surface when we solve the boundary value problem in the external region by boundary element method.

对于深潜物体的N—K问题，用耦合元方法求解不存在根本性的困难，但对于水面船波兴波问题，采用边界元方法来处理外域中的边值问题而出现了所谓的自由面线积分问题。

The regular boundary element method and adaptive boundary element method Yu Dehao, 1989

正则边界元方法与自适应边界元方法

Combining with the element-free method,a boundary element method without singular integration is presented by using non-singular fundamental solution to establish the boundary integral equation for electromagnetic field.

用非奇异基本解建立电磁场问题的边界积分方程，将其与无单元法相结合，提出了电磁场计算的无奇异积分的边界无单元法，编制了相应的计算程序，计算结果表明，方法合理可行。

Based on the profound analysis of cable element and derivation of finite element method, measure of cable element affected by self-weight is put forward after the discussion of the affecting factors of self-weight. Taking full advantage of the UPFs development technology of Ansys, the user-element is developed and the procedure of implementation and technology of development is discussed seriously. And it is helpful to the redevelopment of other similar element.

基于对索单元的深入分析和有限元理论推导，并在对自重的影响因素进行了详细探讨后，提出了考虑自重影响的索单元开发的思路；充分利用基于Ansys的UPFs二次开发技术，开发用户索单元，并深入探讨了实现过程及开发技术，对类似的其它单元的开发有一定的参考价值。

Using linear elastic finite element model for piles and pile cap, elastic-plastic finite element model for piles-surrounding soil under pile cap, linear elastic infinite element model for soil around pile group, and mounting interface element on the pile-soil interfaces, 3-D elastic-plastic finite element method is used to analyzing the pile-soil-cap interaction.

对桩及承台采用线弹性有限元模型，对承台下桩周土采用弹塑性有限元模型，对群桩以外的土体采用线弹性无限元模型，在桩土接触面上设置接触面单元，利用三维弹塑性有限元对桩%D土%D承台相互作用进行了分析。

A method for producing fatty acid alkyl esters and/or glycerin comprising a step of bringing a fat or oil into contact with an alcohol in the presence of a catalyst, wherein the catalyst is at least one catalyst selected from the group consisting of the following to: a metal oxide having an ilmenite structure and/or a slyrankite structure; an oxide containing a metallic element belonging to the Group 12 and a metallic element belonging to the Group 4; a mixed oxide containing a metallic element belonging to the Group 12 and a tetravalent transition metallic element; a metal oxide containing zirconium and at least one metallic element selected from the group consisting of metallic elements belonging to the Groups 4, 5 and 8; and a metal oxide containing anatase type titanium oxide and/or rutile type titanium oxide, and the metal oxide containing a sulfur component of 700 ppm or less.

脂肪酸烷基酯和/或甘油的制造方法包括在催化剂的存在下使脂肪或油与醇接触的步骤，其中，所述催化剂是选自由下列～所组成的组中的至少一种催化剂：具有钛铁矿结构和/或斯里兰卡石结构的金属氧化物；含有属于第12族的金属元素和属于第4族的金属元素的氧化物；含有属于第12族的金属元素和四价过渡金属元素的混合氧化物；含有锆和选自由属于第4、5和8族的金属元素所组成的组中的至少一种金属元素的金属氧化物；和含有锐钛矿型氧化钛和/或金红石型氧化钛的金属氧化物，并且所述金属氧化物含有的硫成分为700ppm以下。

Firstly, this paper investigated roundly the basic theory of the ambient vibration method, analyzed systematically the main methods of ambient vibration identification, and discussed their advantages and disadvantages. Then we established the finite element model of structural dynamics and test model and analyzed their mutual relation, improved MUSIC method and correlation function method in the harmonic identification, and gave the subspace method and correlation function method based on continuous model, which is multi-harmonic retrieve technique. And then, this paper also puts forward least-squares method to estimate directly structural physical and modal parameters; this approach replaced the derivative operator in the continuous time model with an equivalent approximation, and estimated the physical parameters of structures by the least-squares method. And then, we discussed the approximation methods of derivative and their convergence. Finally, this paper researched the modal parameters of a frame structure by the simulation and test. The results demonstrated that subspace method, correlation function method and the least-squares method are effective and stable respectively.

全面地研究环境振动识别方法的基本理论，系统地分析环境振动识别方法的主要方法，讨论它们的优点和不足；建立结(来源：6666AB44C论文网www.abclunwen.com)构动力学的有限元模型和试验模型，分析有限元模型与试验模型之间的相互关系；改进谐波识别中的MUSIC识别方法和相关函数识别方法，给出大型结构模态识别的连续型的子空间分解识别方法和相关函数识别方法，这个方法是多元谐波识别方法；提出直接识别结构的物理参数和模态参数的最小二乘方法，这个方法利用导数的近似值代替导数值，并运用最小二乘方法识别结构的物理参数，讨论导数近似值的选择方法，分析算法的收敛性；通过仿真计算和模型实验，研究高层框架结构的模态参数识别，验证子空间分解识别方法、相关函数识别方法和最小二乘识别方法的有效性，算法的稳定性；从理论和试验两个方面分析和研究噪声对识别精度的影响，影响识别精度的因素，以及部分模态成分的模态参数不能够被识别的原因。

According to the studied results at present, the studied objects are mainly thin plate and beam about sound radiation mode, a method computed sound radiation mode of complex structure is presented in this dissertation, according to the results of the previous two chapter, a theoretical method to solve acoustical radiation mode and acoustical radiation efficiency of complex structure by boundary element method and acoustical radiation theory is posed, the acoustical radiation power is expressed as a Hermitian quadratic form, while the radiation modes is determined by general eigenvalue decomposing, and then the radiation efficiency is computed via the orthodoxy of radiation modes with regard to impedance matrix and average velocity matrix; lastly, the validity of the method is proved by pulsating sphere and radiating cube with analytical results. According to results of the form three chapter, the structure sound radiation sensitivity is studied in detail, the sound radiation power of structure can be expressed as positive Hermitian quadratic form, the sound radiation sensitivity can be expressed as two parts by partial differential with respect to design variable, which are sensitivity of boundary velocity and impedance matrix, combined with the theory of FEM and BEM, the structure sound radiation can be translated to the analysis of structure dynamic sensitivity and impedance matrix sensitivity. The theory posted in this dissertation is tested by the FEM software ANSYS and the software AAS programmed by author.

在前几章的基础上，通过结构声辐射的模态理论对结构的声辐射的机理进行了深入地探讨，针对目前声辐射模态的研究对象主要是简单的板和梁类结构，提出了一种计算复杂结构声辐射模态的方法，利用前两章研究所得的结论，将边界元方法与广义特征值的理论结合起来研究了复杂结构的声辐射模态与声辐射效率，先将结构的声辐射功率表示为一个正定的厄米特二(来源：ABb7C论文0909网www.abclunwen.com)次型，运用广义特征值分解求解了复杂结构的声辐射模态，然后利用声辐射模态关于阻抗矩阵与均方速度耦合矩阵的正交性，求解了复杂结构的声辐射效率，最后用具有解析解的脉动球与辐射立方体验证了该方法的有效性。

Initial boundary value problem of two dimensional unsteady diffusion equations is solved in this paper. By using time-dependent fundamental solution of two dimensional diffusion equations and the extension of double layer potential, we establish virtual boundary integral expression of diffusion equations. Then virtual boundary element method is used to implement the numerical computation.

本文在求解二维非定常扩散方程的初边值问题时，利用二维扩散方程与时间有关的基本解，基于双层位势的延拓，建立二维扩散方程的虚边界积分表达式，然后利用虚边界元法进行数值计算。

The statistical analysis of this large set of mutations has led us to propose a diagnostic strategy that should help with the molecular work-up of optic neuropathies.

这一大系列基因突变的统计学分析引导我们提出一个诊断策略，可以帮助我们对视神经病变进行分子学的诊断检查。

The results show that the pipe grouting changes the mechanical parameters of surrounding rocks to achieve the security of engineering objectives by reinforcing surrounding rocks and bolcking the water.

研究表明：小导管注浆一方面改变了围岩的力学参数，另一方面利用浆液的固结特性可以实现堵水和加固围岩的工程目标，使隧道在开挖过程中的安全得到保障。