The alternating direction implicit method is used to solve discretization equation and supplement block iteration method to quickening convergence.

本文選擇交替方向隱式迭代法，并補(bǔ)以塊修正技術(shù)以促進(jìn)收斂老妇毛多多。

The basic approach of protecting people from being hurt or killed in an accident is to improve crashworthiness of vehicles. This paper starts with discussing theories and methods for vehicle passive safety design, which included experiential methods, analytic methods, multi-body dynamics methods, crash test methods and the finite element method. Emphasis will be paid to the basic FEM theories and algorithms of impact problems. Topics discussed include the governing equation, element discretization, hourglass control, time integration, material model, shell element algorithms and contact-impact algorithms. For more reliable simulation results, this paper then conducts study on how to accurately get material model parameters by combining the FEM method with experimental method, and develops relevant material test machine and parameter calculating software. Based on that, basic typical impact simulation and test validation study are conducted. On the basis of the above work, the paper studies the thin-shell structures'crashworthiness, which was affected by the following factors: spot-weld features, shell thickness, cross-section and pre-deformation. As to vehicle parts'crashworthiness, the paper conducts simulation study of designing energy-absorbing steering system and adaptive airbag system. A practical energy-absorbing steering wheel is designed as an example. In further depth research, the paper suggests several inverse quantificational methods for vehicle crashworthiness design based on the ideal crash characteristics. The above theories and methods are applied with good results through several practical vehicles' crashworthiness design and improvement.

文中對(duì)汽車碰撞安全性的設(shè)計(jì)理論和方法進(jìn)行了歸類和總結(jié)91人妻最真实的绿帽，其中包括經(jīng)驗(yàn)法、解析法一级A片自慰超刺激无码、多剛體動(dòng)力學(xué)法小18箩利洗澡无码视频网站、試驗(yàn)法以及有限元方法等；重點(diǎn)介紹了碰撞有限元法的基本理論和有關(guān)算法91精品www，涉及到有限元求解控制方程什么网站可以免费看A片、單元離散、沙漏模態(tài)控制WWW.午夜一级片.COM、時(shí)間積分午夜精品影院、材料模型和應(yīng)力修正、薄殼單元算法以及接觸碰撞界面算法等jizzjizz18，探討了有限元計(jì)算中的材料模型參數(shù)獲取技術(shù)日韩美女福利网址在线观看视频免费，開發(fā)了相應(yīng)的材料試驗(yàn)裝置及材料模型參數(shù)反求軟件，在此基礎(chǔ)上進(jìn)行了基本的碰撞仿真算例和試驗(yàn)對(duì)比研究一级A片在线看无码免费；文中通過應(yīng)用有限元方法研究了薄壁構(gòu)件的碰撞吸能特性啊啊啊轻点视频，指出了設(shè)計(jì)薄壁吸能構(gòu)件時(shí)需要考慮的幾個(gè)主要影響因素，即焊點(diǎn)欧美阿视频99在、壁厚顶级吹潮视频在线观看、橫截面和預(yù)變形等；在關(guān)于車輛部件的碰撞安全性能設(shè)計(jì)中進(jìn)行了吸能轉(zhuǎn)向機(jī)構(gòu)和自適應(yīng)安全氣囊的仿真研究国产自啪女女，提出了吸能轉(zhuǎn)向機(jī)構(gòu)和自適應(yīng)安全氣囊的仿真研究方法又黄又粗又爽免费观看日本；文中最后探討了整車碰撞性能的設(shè)計(jì)與改進(jìn)方法，提出了以理想碰撞特性為目標(biāo)久久99久久99精品欧美男男，采用分段加速度或者根據(jù)碰撞時(shí)間進(jìn)行設(shè)計(jì)的反推設(shè)計(jì)法美国xxxx69、部件吸能仿真優(yōu)化設(shè)計(jì)法等量化設(shè)計(jì)方法，并通過綜合應(yīng)用文中所討論的相關(guān)技術(shù)進(jìn)行了整車碰撞性能的設(shè)計(jì)與改進(jìn)實(shí)例研究性爽交免费视频，所選定的車型是大眾化的普通轎車和碰撞安全性基礎(chǔ)較差的微型面包車色呦呦在线视频免费观看，研究結(jié)果表明，本文所提出的設(shè)計(jì)與改進(jìn)方法是適用而有效的，具有重要的工程實(shí)用意義和價(jià)值99久久国产综合精品婷婷。

The unique advantage of this halfanalytical numerical method is that the analytical process of Conformal Mapping can transform an irregular area into a regular one such as a rectangle. Therefore, the discretization error of numerical methods on the boundary can be avoided, and the numerical algorithm can be implemented more easily, with the computing efficiency improved.

這種保角變換的半解析數(shù)值方法的突出優(yōu)點(diǎn)是：利用前期的保角變換解析處理將不規(guī)則的場域轉(zhuǎn)化為規(guī)則的矩形域什么视频可以看毛片，從而避免了純數(shù)值技術(shù)對(duì)復(fù)雜邊界的離散化誤差，降低了后期數(shù)值計(jì)算的算法復(fù)雜度91精品视频网，并提高了計(jì)算效率91页国产视频。

This section presents two kinds of characteristic schemes, one is the natural use of the usual backward Euler characteristic difference scheme ( [60] ) onto the triangular mesh, the other replaces the backward Euler's method by modified Euler formula to approximate the characteristic differential equation, so that the discretization for characteristic curve can get up to second order accuracy.

本節(jié)給出了兩種三角形網(wǎng)格上的特征差分格式，第一種是通常的向后Euler型特征差分格式（[60]）在三角形網(wǎng)格上的自然運(yùn)用欧美俄罗斯插插性视频，第二種采用§3.3在线观看免费毛片、§3.4的離散思想，使用改進(jìn)的Euler公式代替向后Euler公式來近似特征微分方程人人干,人人摸人人草，使其對(duì)特征線的離散達(dá)到了二階精度大屌爆艹熟妇无码高清视频。

The approximate method of discretization may be used to calculate the persistent spin current in mesoscopic ring.

用離散化的近似方法也可以計(jì)算介觀環(huán)中的持續(xù)自旋流。

Chapter 9: We report a large quantity of numerical experiments of 13 different algebraic multigrid algorithms for solving the Poisson equation, anisotropic equation, equation with cross-derivative terms, general matrix problems with large off-diagonal positive entries, biharmonic equation, Toeplity matrix, elasticity systems, finite element discretization of the Laplacian and even 3D problems. Particular attention is focused on asymptotic convergence factors and CPU-time consumed. Numerical results for many different types of practical problems demonstrate the efficiency and robustness of the proposed algebraic multigrid methods.

第九章：在各種代數(shù)多重網(wǎng)格算法的基礎(chǔ)上91在线九色，進(jìn)行了大量的數(shù)值試驗(yàn)碰碰精品插下面日本美女去了，具體給出了十三種不同的代數(shù)多重網(wǎng)格方法求解泊松方程，各向異性方程好爽好大好紧别拔出来视频，帶混合導(dǎo)數(shù)項(xiàng)的方程911在线观看国产涩涩，帶有大的非對(duì)角正元素的一般矩陣問題，重調(diào)和方程在线高清免费不卡无码黄片，托普利茲矩陣80老女人乱婬视频，彈性力學(xué)方程組，拉普拉斯算子的有限元離散欧美黄片天天在线观看，甚至三維問題的較為豐富的數(shù)值結(jié)果717电影网理论片我不卡，重點(diǎn)關(guān)注它們的漸近收斂因子和所需的CPU時(shí)間，來源于不同類型問題的計(jì)算結(jié)果既為代數(shù)多重網(wǎng)格理論分析和算法的改進(jìn)提供了很實(shí)用的資料男女人精品视频站在线观看，同時(shí)也證實(shí)了本文給出的代數(shù)多重網(wǎng)格算法的效績和穩(wěn)健性一级黄色视频免费观看。

In the process of discretization of the auxiliary function, the traditional central difference formula is replaced by the backward difference formula, and numerical results show the method is of good stability.

在輔助函數(shù)的離散過程中用后向差分公式代替?zhèn)鹘y(tǒng)的中心差分公式，數(shù)值結(jié)果顯示出良好的穩(wěn)定性亚洲色图五月天综合。

In Section 3, the BEM and the corresponding constant-element discretization is presented.

在第3條中俄罗斯网站人人草人人干在线观看，邊界元法和相應(yīng)的常數(shù)元離散。

Major research work and conclusions are summarized as follows:1 The development of molecular distillation are reviewed in respect of the principle, model research and application; The technical and structure parameters are analyzed with respect to the evaporation rate and separation factor.2 Based on analysis of heat transfer and mass transfer process in WFMD, the discretization forms of bow wave ordinary differential equations and film partial differential equations are obtained with Runge-Kutta method and finite difference method respectively.

主要工作與研究結(jié)果如下： 1 綜述分子蒸餾技術(shù)的應(yīng)用及其發(fā)展現(xiàn)狀98在线视频，從分子蒸餾技術(shù)的原理人人摸人人搞人人草、模型研究及其應(yīng)用的發(fā)展等進(jìn)行了系統(tǒng)評(píng)述；并結(jié)合蒸發(fā)速率和分離效率這兩個(gè)評(píng)價(jià)分子蒸餾效果的重要指標(biāo)av男人的天堂综合网，對(duì)刮膜分子蒸餾器工藝參數(shù)與結(jié)構(gòu)參數(shù)進(jìn)行了分析與討論亚洲成av人仙踪林。

It is shown that in Jameson's algorithm is not an orthogonal stream-lines coordinate system, but a local stream-lines coordinate system instead. Nevetheless, because of the finite-difference discretization in Jameson's scheme is not carried out along the direction of s and n, but along the Cartesian coordinates, the analysis on all terms of the full potential equation in Cartesian coordinates reveals that his scheme does take a back-ward difference along the streamwise exactly at all points in the supersonic flow region.

表明其所采用的坐標(biāo)系不是真正的正交流線坐標(biāo)系，而是局部流線坐標(biāo)系国产精品视频久久；同時(shí)由于Jameson方法并不對(duì)s，n進(jìn)行差分離散，而是在原笛卡爾坐標(biāo)系下作差分離散三级免费观看网站，對(duì)笛卡爾坐標(biāo)系下的全位勢方程中的各項(xiàng)的分析表明韩国午夜理伦三级2020不卡，Jameson方法恰好能做到在超音速點(diǎn)沿真正的流線方向作后差分。