FLOW-CONVERTER

Connection type FLOW-CONVERTER converts the relative rotation about a user-specified axis between the two nodes of the connector into material flow degree of freedom (10) at the second node of a connector element. This connection type can be used to model retractor and pretensioner devices in automotive seat belts (see Seat belt analysis of a simplified crash dummy) or cable drums in winch-like devices. Belt or cable material is considered to be wrapped around an axle or a drum, and material can be spooled either into or out of the connector element.

In certain cases, material flow needs to be converted into a displacement rather than a rotation. Examples include pretensioner devices for which experimental force vs. displacement data need to be specified. Although this connection type always converts the material flow into a rotation, the two modeling cases are equivalent. The experimentally available force vs. displacement data can be input directly as moment vs. rotation data for the same end result.

This connection type activates degree of freedom 10 at the second node of a connector. As with any other nodal degree of freedom, you must be careful in constraining it. This is typically done by attaching the connector to a SLIPRING connector that is part of the belt system or by applying a boundary condition. FLOW-CONVERTER connections cannot be used in two-dimensional and axisymmetric analyses in Abaqus/Explicit.

This page discusses:

See Also
Connector Elements
Connector Element Library
In Other Guides
*CONNECTOR BEHAVIOR
*CONNECTOR SECTION

ProductsAbaqus/StandardAbaqus/ExplicitAbaqus/CAE

Description

Figure 1. Connection type FLOW-CONVERTER.

The FLOW-CONVERTER connection constrains the relative rotation between the two nodes about the third local direction, e3a, to the material flow at node b, Ψb. The constraint can be written as

u⁢r3=e3a⋅(θa-θb)-βs⁢Ψb=0,

where θa-θb is the relative nodal rotation between node a andb and βs is a scaling factor specified as part of the associated connector section definition. By default, βs=1.0. The local direction e3a rotates with the nodal rotation at node a.

There are no available components of relative motion for this connection type; hence, kinetic behavior cannot be specified. However, the following kinematic quantities are available for output:

u⁢r1=e3a⋅(θa-θb)    and    u⁢r2=Ψb,

which will be output as CPR1 and CPR2, respectively.

The constraint moment is

m¯=m3⁢e3a.

Limitation

At most two FLOW-CONVERTER connectors can share their second node where degree of freedom 10 is active.

Summary

FLOW-CONVERTER
Basic, assembled, or complex: Specialized basic rotational
Kinematic constraints: u⁢r3=0
Constraint moment output: m3
Available components: None
Kinetic force output: None
Orientation at a: Required
Orientation at b: Ignored
Connector stops: None
Constitutive reference lengths: None
Predefined friction parameters: None
Contact force for predefined friction: None