浅谈一下阻尼知识

Pseudo-lover

主要分为两种，材料阻尼和数值阻尼：

一、材料阻尼

1.瑞雷阻尼（Rayleigh damping）

（1）质量阻尼Alpha：消除低频区

      

*DAMPING, ALPHA=

（2）刚度阻尼Beta：消除高频区

      

*DAMPING, BETA=

2.结构阻尼

结构阻尼适用于频域动力分析。

它的假定是阻尼力和结构力成正比，和速度成反比，即该阻尼适用条件是位移和速度的相位相差90度。

Use the following option to define damping by specifying mode numbers:

*MODAL DAMPING, STRUCTURAL, DEFINITION=MODE NUMBERS

Use the following option to define damping by specifying a frequency range:

*MODAL DAMPING, STRUCTURAL,DEFINITION=FREQUENCY RANGE

二、数值阻尼（无物理意义）

1.直接积分动力分析（隐式）

HHT求解法，引入数值阻尼参数alpha，该值同前述的不一样。该值同时间增量和周期的比值有关。

      

*DYNAMIC, ALPHA=

2.显式积分动力分析

引入体积粘度来控制高频振动。

Use the following option to define bulk viscosity for the entire model:

*BULK VISCOSITY

Use the following options to define bulk viscosity for an individual element set:

*BULK VISCOSITY

*SECTION CONTROLS

三、模态叠加求解法中的阻尼

1.临界阻尼比例

Use the following option to define damping by specifying mode numbers:

*MODAL DAMPING, MODAL=DIRECT,DEFINITION=MODE NUMBERS

Use the following option to define damping by specifying a frequency range:

*MODAL DAMPING, MODAL=DIRECT,DEFINITION=FREQUENCY RANGE

2.瑞雷阻尼

Use the following option to define damping by specifying mode numbers:

*MODAL DAMPING, RAYLEIGH, DEFINITION=MODE NUMBERS

Use the following option to define damping by specifying a frequency range:

*MODAL DAMPING, RAYLEIGH, DEFINITION=FREQUENCY RANGE

3.复合模态阻尼

*DAMPING, COMPOSITE= *MODAL DAMPING, MODAL=COMPOSITE

4.结构阻尼

Use the following option to define damping by specifying mode numbers:

*MODAL DAMPING, STRUCTURAL,DEFINITION=MODE NUMBERS

Use the following option to define damping by specifying a frequency range:

*MODAL DAMPING, STRUCTURAL,DEFINITION=FREQUENCY RANGE

最后引用ABAQUS的一句原话：

In direct-integration dynamic analysis you very often define energy dissipation mechanisms—dashpots缓冲, inelastic material非弹性材料 behavior, etc.—as part of the basic model. In such cases there is usually no need to introduce additional damping: it is often unimportant compared to these other dissipative effects.

转自：http://blog.sina.com.cn/s/blog_49c02a8c0100yt0q.html