element

你可以选择保持不变或刚性横截面。

缩放不是非线性梁截面选择

（

sectype

，

，

genB

）

。

Two limitations are associated with the quadratic and cubic options in BEAM188:

两个限制与二次和三次选项

BEAM188

相关：

Although the elements employ higher-order interpolations, the initial geometry of

BEAM188 is treated as straight.

虽然元件采用高阶插值，

BEAM188

初始几 何作为直。

Because the internal nodes are inaccessible, no boundary/loading/initial conditions are

allowed on these internal nodes.

由于内部节点是无法访问的，没有边界

/

加载

/

初始条件对这些内部节点允许。

As a result of the limitations associated with the quadratic and cubic options, you will

notice discrepancies in the results between BEAM189 and the quadratic option of

BEAM188 if the midside nodes of the BEAM189 model have specified

boundary/loading/initial conditions and/or the midside nodes are not located exactly at

the element midpoint. Similarly, the cubic option of BEAM188 may not be identical to a

traditional cubic (Hermitian) beam element.

作为一个结果，与二次和三次选项，相关联的限制，你将在商业软件 模型中节点指定边界

/

加载

/

初始条件和

/

或中间节点不准确定位在单元中点 通知

Beam189

和

BEAM188

二次选

项的结果之间的差异。同样，

B EAM188

立方选项可能不到传统的立方相同（埃尔米特）

梁 单元。

For the mass matrix and evaluation of consistent load vectors, a higher order integration

rule than that used for stiffness matrix is employed. The elements support both

consistent and lumped mass matrices. Use LUMPM,ON to activate lumped mass matrix.

Consistent mass matrix is used by default. An added mass per unit length can be input

with the ADDMAS section controls. See

对于质量矩阵和载荷向量的一致评价，

采用高阶积分规 则比刚度矩阵使用。

单元支持一致

和集中质量矩阵。

lumpm

，

在激活 集中质量矩阵。

一致质量矩阵是使用默认的。

增加

每单位长度质量可与

addmas

部分控制输入。见

“BEAM188

输入概述

”

。

The St. Venant warping functions for torsional behavior are determined in the

undeformed state, and are used to define shear strain even after yielding. No options

are available for recalculating in deformed configuration the torsional shear distribution

on cross- sections during the analysis and possible partial plastic yielding of

cross-sections. As such, large inelastic deformation due to torsional loading should be

treated and verified with caution. Under such circumstances, alternative modeling using

solid or shell elements is recommended.

圣维南翘曲扭转作 用引起的行为是在未变形的状态决定的，

甚至可以用来定义屈服后剪应

< br>变。

没有可供选择的重新配置的扭转剪切变形对截面和可能的局部塑性屈服的截面 分析的

过程中。因此，非弹性大变形扭转荷载应被视为谨慎和验证。在这种情况下，使用 固体或

壳单元是推荐的替代建模。

BEAM188 Input Data

Beam188

输入数据

The geometry, node locations, coordinate system, and pressure directions for this

element are shown in Figure 188.1: BEAM188 Geometry. BEAM188 is defined by nodes

I and J in the global coordinate system.

几何，

节点位置，

坐 标系统，

和该元素的压力方向如图

188.1

< br>所示：

BEAM188 Geometry

。

是在全局坐标系的节点

i

和

j

定义。

Node K is a preferred way to define the orientation of the element. For information about

orientation nodes and beam meshing, see Generating a Beam Mesh With Orientation

Nodes in the Modeling and Meshing Guide. See the LMESH and LATT command

descriptions for details on generating the K node automatically.

节点

k

是首选的方式来定义元素的定位。

关于定位节点和梁的网格信 息，看到产生一个与

啮合指导建模定位节点梁网。看到在

k

节点自动生成的详细

lmesh

和

LATT

命令描述。

BEAM188 can also be defined without the orientation node K. In this case, the element

x-axis is oriented from node I (end 1) toward node J (end 2). If no orientation node is

used, the default orientation of the element y-axis is automatically calculated to be

parallel to the global X-Y plane. For the case where the element is parallel to the global

Z-axis (or within a 0.01 percent slope of it), the element y-axis is oriented parallel to the

global Y-axis (as shown). To control the element orientation about the element x-axis,

use the orientation-node option. If both are defined, the orientation-node option takes

precedence. The orientation node K, if used, defines a plane (with I and J) containing

the element x and z-axes (as shown). If using this element in a large-deflection analysis,

be aware that the location of the orientation node K is used only to initially orient the

element.

Beam188< /p>

也可以定义未定位节点

K

。

在这种情况下，

单元的

x

轴 方向为从节点

i

（

1

< br>年底）

对节点

j

（

2

年底）。如果没有定位节点使用的元素，

Y

轴默认方向自动计算是平行于全局

X-Y

平面 。对于元件平行于全局

Z

轴（或百分之

0.01

坡元内），

y

轴的方向平行于 全局坐

标（如图所示）。控制单元的

x

轴方向的元件，使用定位节点的选项。如果两者都定义，

定位节点的选项优先考虑。定位 节点

k

，如果使用，定义一个平面（

I

和

J

）含有元素

X

和

Z

轴（如图所示）。如果使用这 个元素在大挠度分析，要注意定位节点

k

位置是只用于初

步定位元素。

The number of degrees of freedom depends on the value of KEYOPT(1). When

KEYOPT(1) = 0 (the default), six degrees of freedom occur at each node. These include

translations in the x, y, and z directions and rotations about the x, y, and z directions.

When KEYOPT(1) = 1, a seventh degree of freedom (warping magnitude) is also

considered.