迭代过程

Aiming at the strong coupling characteristic during the multi-disciplinary optimization process of hypersonic aerocraft, in order to reduce computing time and increase the feasibility of optimization process, this paper adopted the approximate method to build the responding model between disciplines, In this paper, under the condition of ensuring the engine stable and high efficient , the designing work also consider the whole aerocraft performance sufficiently from the effect of forebody and afterbody.

针对高超音速飞行器多学科设计优化过程中的强耦合特性，为了减少计算时间，提高优化过程的可行性，采用近似的方法来建立学科之间的响应模型，以此来减少每次迭代时所用的大量计算时间。

In the proposed algorithm the traditional fixed step size iteration is substituted by time-varying step size iteration to improve the accuracy of directional estimation while the minimum mean square deviation is solved to achieve the purpose of increasing the convergence speed of the proposed algorithm.

以一种时变步长迭代方法取代传统的定步长迭代法，旨在提高算法在求取均方差最小值的过程中方向估值的精度，从而达到提高算法收敛速度的目的。

An iteration procedure for improving design variables is constructed by this optimality criterion, and a factor is also employed to control the step size in order to make the iterative process be stable.

根据导出的优化准则构造出一种修改设计变量的迭代格式，其中引入松弛因子以保证收敛过程的稳定，并在每次迭代开始前都利用射线步把设计点引至可行域的边界上。

Richardson iterative method is adopted to restore the image degraded by thick pinhole. The stopping rule of the iteration is determined by the simulation results.

针对厚针孔成像过程的空间移变性，采用Richardson迭代法进行图像复原处理，取得了满意的复原效果，并提出迭代次数的确定方法。

The constructing process of the algorithms itself indicate that they are brevity and have definite geometric meaning, scientific iterative terminal criterions and no strict requirement to function. Finally, some digital experimentation is presented to indicate the algorithms application in solving the problem of maximum of function, transcendental equation,integer programming and so on. The results indicate that the algorithms have more global and more adaptability compared to traditional algorithms and have more calculating efficiency and more scientific iterative terminal criterions compared to some present popular artificial intelligence algorithms.

算法的构造过程本身表明了该算法简单明了、几何意义明确、迭代终止准则科学、对函数的要求较低；最后举了几个数值试验的例子以说明该类算法在求函数的最值，解超越方程以及整数规划等问题中的应用；数值试验的结果标明该算法比单纯由"微分"思想演化而来的传统算法有更好的全局性和对问题的更广泛的适应性，比现在流行的一些人工智能方法有更高的运算效率和更适当的迭代中止准则。

In this paper, the generator model of constant transient voltage and the invariableness impedance model was used, and the saliency of generator is included; through the analysis of the characteristic of the network equation calculation in the transient stability analysis, a new node ordering algorithm is proposed. Better initial value can accelerate the convergence rate of the networking equations, reduce the number of iterations, thus to cut down the amount of calculating time.

本文首先建立了适合于暂态稳定分析的简单模型，其中发电机采用E_q恒定模型，考虑了发电机的暂态凸极效应，负荷采用恒定阻抗模型；研究了电力系统的暂态稳定分析方法，指出目前数值积分暂态稳定计算方法中存在的不足，主要是网络方程的求解速度过慢；分析了暂态稳定计算中网络方程的特点，将稀疏技术应用于网络方程的求解，提出了一种新的节点编号方法——最小度最小有源节点道路集算法，减少了网络方程的计算量；在进行交替迭代求解时，将预测算法应用于每一积分步网络方程功角和电压的初值估计当中，应用自回归算法和广义延拓算法，期望给出一个更有效的电压和功角初值方案，来加快方程的收敛过程，减少方程迭代的次数，以提高计算速度。

This method solves the problem of nonlinear iterative oscillation successfully and expedites the convergence velocity.

运用该模型解决了土壤冻融相变过程中非线性迭代的振荡问题，加快了迭代收敛速度。

3D-CTM (Coupled Thermo-Mechanical Forming Simulation) software for precision forging process of aero-engine blade was developed. The key technologies of 3D coupled rigid-viscoplastic thermo-mechanical FEM simulation of blade forging process were studied systematically. By using the remeshing method of contracting from the boundary to the inner, new mesh system from old distorted mesh system can be obtained. A method of modifying the position of nodes touching on the die according to its original normal was proposed to avoid "dead lock" problem due to uncontinuity of normal of scatted die meshes. The pseudo-static iterative algorithm was used to simplify the coupled thermo-mechanical computation. In particular, formulations to determine relaxation factor β was established for rigid viscoplastic FEM adopting penalty function method, and an improved cubic factor rapid algorithm derived from these formulations was proposed by combining with the advantage of advance and retreat search method.

采用基于边界构形的内缩法，实现了三维畸变网格的重新划分；提出了初矢修正法对触模节点的位置进行修正，解决了由于离散的模具网格的法矢不连续造成的&死锁&问题；采用准静态迭代法简化了速度场和温度场耦合计算过程；特别是针对减速因子β的选取，建立了适用于三维复杂成形过程刚粘塑性罚函数法有限元三次因子法的计算公式，并结合进退搜索法提出了改进的三次因子快速算法，提高了模拟计算效率和稳定性，在此基础之上，开发了面向叶片精锻过程的三维刚粘塑性热力耦合有限元模拟分析系统(3D-CTM)，系统的可靠性得到了圆柱体镦粗的验证。

According to the analysis and computational results in this thesis, although the actual structure and work conditions of the pressure vessel in nuclear power station are much more complex than that of the pressure vessel model, the program FEARPV still can get quite good convergence on the plasticity andcontact iteration. And also the program FEARPV has good value stability, and good regularity. During the heating, compression, constant temperature, constant pressure, cooling and decompression process, the regularity is basically in common with that of the pressure vessel model.

由本文分析计算可知，虽然电站核压力容器的结构及计算工况较压力容器模拟体复杂得多，然而反应堆压力容器瞬态密封有限元分析程序对塑性迭代和接触迭代仍具有很好的收敛性，数值稳定性好，得到的结果具有良好的规律性，在升温、升压、恒温、恒压、降温和降压等过程中其规律和压力容器模拟体基本相似。

For non-intense beams,particle trajectory can be obtained by multiplying linear transport matrices. For nonlinear transport of intense beams,the influence of space-charge effect on beam transport needs to be taken into account,and self-consistent solution should be derived because of the interaction between charged particle distribution and space charge field. In the program,components and currents are divided into equal intervals,respectively,and each interval is treated as a uniform solenoid field.

程序在计算非强流脉冲束流的线性传输时，粒子的轨迹通过矩阵的直接相乘计算得出；程序在计算强流脉冲束流的非线性传输时，需要考虑束流中的空间电荷效应对束流传输的影响，在束流运动过程中，空间电荷场也在不断地变化，而且粒子运动的轨迹与空间电荷势又是相互依赖的，因此需要求得一个自洽的解，先把元件分成若干均等的区间，把电流分成若干等份，后采用束流电流迭代与元件区间迭代的计算方法。

As she looked at Warrington's manly face, and dark, melancholy eyes, she had settled in her mind that he must have been the victim of an unhappy attachment.

每逢看到沃林顿那刚毅的脸，那乌黑、忧郁的眼睛，她便会相信，他一定作过不幸的爱情的受害者。

Maybe they'll disappear into a pothole.

也许他们将在壶穴里消失