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LINK167

Explicit Tension-Only Spar DY

Product Restrictions

LINK167 Element Description

LINK167 allows elastic cables to be realistically modeled; thus, no force will develop in compression.

This element is used in explicit dynamic analyses only.

Figure 167.1 LINK167 Geometry

LINK167 Input Data

The geometry, node locations, and the coordinate system for this element are

shown in Figure 167.1. Node K determines the initial orientation of the cross section.

The element is defined by nodes I and J in the global coordinate system. Node K

defines a plane (with I and J) containing the element s-axis. The element r-axis runs parallel to the length of the element and through nodes I and J. Node K is

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runs parallel to the length of the element and through nodes I and J. Node K is

always required to define the element axis system and it must not be colinear with nodes I and J. The location of node K is used only to initially orient the element.

Real constants for this element are link area (AREA) and offset for cable (OFFSET).

For a slack element, the offset should be input as a negative value. For an initial tensile force, the offset should be positive.

The force, F, generated by the link is nonzero if and only if the link is in tension. The force is given by:

F = K max ( L,0.)

where L is the change in length

L = current length - (initial length - offset)

and the stiffness is defined as:

You can use only the material type cable for this element. For this material, you

need to define the density (DENS) and Young's modulus (EX) or load curve ID. If you specify a load curve ID (EDMP,CABLE,VAL1, where VAL1 is the load curve

ID), the Young's modulus will be ignored and the load curve will be used instead.

The points on the load curve are defined as engineering stress versus engineering strain (that is, the change in length over the initial length). Use the EDCURVE

command to define the load curve ID. The unloading behavior follows the

loading.

Base accelerations and angular velocities in the x, y, and z directions can be

applied at the nodes using the EDLOAD command. To apply these loads, you

need to first select the nodes and create a component. The load is then applied to that component.

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A summary of the element input is given in "LINK167 Input Summary".

Additional information about real constants for this element is provided in Table 161.1: BEAM161 Real Constants. For more information about this element,

see the LS-DYNA Theoretical Manual.

LINK167 Input Summary

Nodes

I, J, K (K is the orientation node)Degrees of Freedom

UX, UY, UZ, VX, VY, VZ, AX, AY, AZ

Note: For explicit dynamic analyses, V(X, Y, Z) refers to nodal

velocity, and A(X, Y, Z) refers to nodal acceleration.

Although V(X, Y, Z) and A(X, Y, Z) appear as DOFs, they are not actually physical DOFs. However, these

quantities are computed as DOF solutions and stored

for postprocessing.

Real Constants

AREA - Cross-sectional area

OFFSET - Offset value for cable

Material Properties

EX (MP command) or Load Curve ID (EDMP command),

DENS (MP command),

ALPD (MP command), BETD (MP command),

CABLE (EDMP command; see Material Models in the ANSYS LS-DYNA User's Guide)

Surface Loads

None

Body LoadsNone

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None

Special FeaturesAll nonlinear features allowed for an explicit dynamic analysis.

KEYOPTs

None

LINK167 Output Data

Output for LINK167 consists of the following: Axial force

To output the data, you must use the ETABLE command. For the ITEM label,

specify SMISC. For the COMP label, specify 1 for axial force. Then, you can use the

PRETAB command to print the output data.

LINK167 Assumptions and Restrictions

The sum of the element length plus the offset must be greater than zero.The cross-sectional area must be greater than zero.

LINK167 Product Restrictions

There are no product-specific restrictions for this element.

Release 14.0 - 2011 SAS IP, Inc. All rights reserved.