阻尼法

The way to calculate the added-mass and the damping coefficient of the ship sections by conformal mapping and pulsating source method.

重点介绍了用多级展开法和源汇分布法求解船体切片段的附加质量及阻尼系数。

In this paper, the JFO condition, satisfied with global mass continuity, is incorporated into an universal Reynolds equation with micro-polar fluid which is solved for the oil film pressure using OSM and FEM. The bearing load capacity and friction resistance were given, and stiffness/damping coefficients and critical rotor mass were obtained by solving a pressure perturbation equation with micro-polar lubricants.

本文采用满足全流场质量连续的JFO边界条件，采用微极性流体的广义雷诺方程来求解油膜压力分布，进而获得油膜承载力和粘性阻力等轴承动力特性量；采用小参数摄动法得出油膜压强扰动方程，并采用有限元法解出扰动压强，积分扰动压强获得油膜的阻尼系数和刚度系数，进而求得了表示轴承油膜稳定性的临界转子质量。

In this paper,using the improved L-P method and the interpolation perturbation method,the authors seek to solve a class of the damped strongly nonlinear free oscillation problems.

文摘：本文用插值摄动法及改进的L-P法相结合的方法求解了一类有阻尼的强非线性自由振动问题，得到了一级近似解。

The estimation methods of damping factor of bellows under noise environment by free vibration response were presented.

利用小波去噪抑制测量噪声的影响，采用Hilbert变换法和峰值法估计波纹管的阻尼系数。

A variable-step modified Euler time integration method is proposed and analyzed. Four major factors that affect the efficiency of the variable-step modified Euler time integration method are discussed. These include stability and accuracy analysis for the damped fix-step modified Euler integration formula, adjustment method of the fix-step basic integration formula to accommodate step-size changes, suitable range of the step-size selection strategy based on truncation error concept and development of the step-size selection strategy based on apparent frequency concept to satisfied the specified error bound and stability condition.

提出了变步长修正Euler时间积分法，详细讨论了影响变步长修正Euler时间积分算法效率的四个主要因素，它们包括：有阻尼问题的修正Euler法的稳定性和精度分析，调整固定步长的基本积分公式使之容纳步长大小变化的研究，基于截断误差概念的步长大小选择策略适用范围的讨论，同时满足规定误差界和稳定性条件的、基于表观频率概念的步长大小选择策略的建立。

The acting force needn't to be monotonic or harmonic. A series of simulations of a fan blade with shroud system has been carried out.

基于解析模型和离散模型，本文分别采用频域法和时域法对凸肩阻尼叶片进行了受迫振动响应分析。

Then steady forced vibration of the nonlinear Disk spring-mass system under base excitation and force excitation is obtained individually by using the Fourier series analysis and harmonic balance method.

详细探讨了考虑静力载荷影响的、具有弹性非线性和Coulomb摩擦阻尼非线性的碟簧元件的建模和动力学特性，首先利用Fourier级数分析技巧和平均法研究了非线性碟簧-质量系统的自由振动，讨论了影响自由振动的振幅和频率的各种因素，然后利用Fourier级数分析技巧和谐波平衡法研究了地基激励和力激励下非线性碟簧-质量系统的强迫振动，通过详细的参数研究考察了非线性碟簧元件的减振性能特征，最后采用修正的稳定性分析方法研究了两种激励下稳态响应的稳定性。

Finite element method is used in the study of nozzle damping of instable combustion in a solid rocket motor.

应用有限单元法研究固体火箭发动机不稳定燃烧中的喷管阻尼，并用波衰减对比法进行了试验研究。

According to Floquet theory and transition curves of Mathieu equation, two different modified strained parameter methods are compared on precision of periodic solutions. The effect of viscous damp on parametrical rolling stability is analyzed with the modified strained parameter method.

根据Floquet理论和方程的稳定性过渡曲线，比较2种不同改进变形参数法的求解精度，利用改进变形参数法来分析黏性阻尼变化对参数横摇稳定性的影响。

On the problem of model parameter determination, the singularity distribution method is used to derive the expressions for numerically calculating the added mass arised from vibration of the structure under three-dimensional case; The aero-dynamic damping ratio is identified from the testing data based on the methods of empirical mode decomposition, improved random decrement and Hilbert transformation; The reduced-order spectral representation method is also deduced in this chapter based on the technique of proper orthogonal decomposition.

在模型的参数计算上，采用奇点配置法推导了三维情形下结构振动诱导流场附加质量的数值计算方法；联合采用经验模态分解、改进的随机减量法及Hilbert变换对索穹顶结构的气动阻尼进行了识别分析；推导了基于本征正交分解的降阶谱解法。

Cynanchum Lingtai apricot production in the average weight 65 grams, the brightly-colored fruit, juicy rich, sweet-sour taste, sweet from the nucleolus, when the late Qing Dynasty famous Shaanxi, Gansu provinces, the Qing imperial court Tongzhi tribute for years.

灵台生产的牛心杏平均单果重65克，果实色泽鲜艳，汁多味浓，甜酸适口，离核仁甜，清末时就驰名陕、甘两省，清同治年间曾为朝廷贡品。

Chenopodium album,Solanum nigrum, and Amaranthus retroflexus were very susceptible to the herbicides. Polygonum persicaria and Abutilon theophrasti were relatively less susceptible to the herbicides, and Lycopersicon esculentum was not susceptible to it. The relationship between reduction rates of weed biomass and PPM values of weed leaves 2,4, and 6 days after treatment was established.

供试的6种杂草对该混剂的敏感性存在显著差异：红心藜Chenopodium album、龙葵Solanum nigrum和反枝苋Amaranthus retroflexus对该混剂最敏感，ED90值分别为47.65、71.67和29.17g/hm2；春蓼Polygonum persicaria和苘麻Abutilon theophrasti敏感，ED90值分别为96.91、114.20g/hm2；而番茄不敏感。