22.1.4 - Frictional - behavior - - 摩擦行为(5)

的“Lagrange multiplier method for imposing frictional constraints in ABAQUS/Standard）。

The default value of allowable elastic slip used by ABAQUS/Standard generally works very well, providing a conservative balance between efficiency and accuracy. ABAQUS/Standard calculates as a small fraction of the “characteristic contact surface length,” , and scans all of the facets of all the slave surfaces when calculating . ABAQUS/Standard reports the value of used for each contact pair in the data (.dat) file. The allowable elastic slip is given as tolerance; the default value of

is 0.005.

, where

is the slip

在ABAQUS/Standard里许用弹性滑移的默认值通常很凑效，假如是保守的平衡效率和精度。ABAQUS/Standard计算时将它作为“接触面特征长度”的一个小分数，还在计算时扫描从面上所有的小面。ABAQUS/Standard 将接触对中用到的值报告到数据文件（.dat）里。许用弹性滑移为差，默认

值是0.005。

，其中

是滑移公

This method of calculating the allowable elastic slip is used for all analysis procedures in ABAQUS/Standard except steady-state transport analysis (“Steady-state transport analysis,” Section 6.4.1), in which the penalty constraint is based on a maximum allowable slip rate, . The maximum slip rate is calculated as

where is the angular spinning rate and is the radius of the rolling structure.

这种计算许用弹性滑移的方法适用于所有ABAQUS/Standard分析，除了稳态传送分析（“Steady-state transport analysis,” Section 6.4.1），在该分析中罚函数约束基于最大许用滑移率。最大滑移率计算式为：

其中是旋转角速率，是旋转结构的半径。

In certain situations the default value for the allowable elastic slip may not be suitable. For instance, slave surfaces defined by node-based surfaces or some contact element types, such as GAPUNI elements, have no

physical dimensions and ABAQUS/Standard cannot estimate a value of . For models containing only node-based surfaces or these types of contact elements, ABAQUS/Standard first tries to use the “characteristic contact surface length” of the other contact pairs in the model. If there are none, it calculates using all of the elements in the model and issues a warning message. If a model contains no elements for which a characteristic length can be determined (for instance, if it contains only substructures), ABAQUS/Standard has no information with which to calculate . As a result, it uses a value of 1.0 and issues a warning message. If the contact surface face dimensions vary greatly, the average value of may be unreasonable for some contact surfaces. The elastic slip should then be specified directly for the surfaces with a much smaller “characteristic face dimension.”

在一些特定情形里默认许用弹性滑移值可能不合适。比如基于节点的面的从面或一些接触单元类型，像GAPUNI单元，就没有物理尺寸，ABAQUS/Standard不能估计一个值。对于包含基于节点面或接触单元的模型， ABAQUS/Standard首先试着用模型里其它接触对的“接触面特征长度”。如果没有，它将用模型里的所有单元来计算并发出警告信息。如果模型没有单元可以确定特征长度（比如，模型只含有子结构），ABAQUS/Standard没有计算的信息。结果，它用1.0这个值并发出警告信息。如果接触面尺寸变化非常大，一些接触面的平均值可能不合理。这时候应该直接用一个小的多的“特征尺寸”为接触面指定弹性滑移。 There are two methods for modifying the allowable elastic slip. One method is to specify directly; the other is to specify the slip tolerance, . 有两种方法来修改许用弹性滑移。一种是直接指定；另一种是指定滑移公差

?

。

You can provide the absolute magnitude of directly. Specify a

reasonable value for the relative displacement that may occur before surfaces actually begin to slip. Typically, the allowable elastic slip is set to a small fraction (10–2–10–4) of a “characteristic contact surface face dimension.” In a steady-state transport analysis you can define the maximum allowable viscous slip rate, .

?

你可以直接规定的绝对大小。为接触面开始滑动前可能发生的相对位移指定一个合理值。典型的，许用弹性滑移设置为“接触面特征尺寸”的一个很小的分数（10–2–10–4）。在稳态传送分析中，你可以定义最大许用粘性滑移率。

The specified allowable elastic slip will be used only for the contact pairs referencing the contact property definition that contains the friction definition. For example, three surfaces ASURF, BSURF, and CSURF form two contact pairs that each refer to their own contact property definition, as shown below. In the DEFAULT contact property definition no value for is specified, so the allowable elastic slip used for the friction interaction between ASURF and BSURF would be the default value

. In the NONDEF

contact property definition a value of 0.1 is specified for , which will be the allowable elastic slip used for the friction interaction between CSURF and BSURF.

指定的许用弹性滑移只用于接触对，参考在接触属性里定义摩擦。例如三表面ASURF，BSURF和CSURF形成两接触对，每个接触对有各自的接触属性定义，如下所示。默认接触属性定义没给赋值，所以用于ASURF和BSURF接触摩擦属性定义的许用弹性滑动为默认值

。在NONDEF接触

属性定义里给赋值0.1，该值将成为CSURF和BSURF间摩擦接触的许用弹性滑移。

Contact Pair Contact Property ASURF, BSURF DEFAULT CSURF, BSURF NONDEF

Input File Usage: *FRICTION, ELASTIC SLIP=

ABAQUS/CAE Usage: Interaction module: contact property editor:

MechanicalTangential Behavior: Friction formulation: Penalty or Static-Kinetic Exponential Decay: Elastic Slip, Absolute distance:

0.1 Alternatively, you can alter the default value of the slip tolerance, . This method of altering the default elastic slip is convenient if the goal is to increase computational efficiency, in which case a value larger than the default of 0.005 would be given, or if the goal is to increase accuracy, in which case a value smaller than the default would be given.

? 你可以改变滑移公差的默认值。这种改变默认弹性滑移的方法 …… 此处隐藏：6602字，全部文档内容请下载后查看。喜欢就下载吧 ……