# Metafor

ULiege - Aerospace & Mechanical Engineering

### Sidebar

doc:user:geometry:user:contours

﻿

# Wires

## Definition

A Wire is a set of Curves, used for example to create a Side. Wires can be open, closed, and even discontinuous. However, some operations, such as meshing, can only be applied to specific Wires.

The orientation of a Wire is given by the succession of its lines (see figure above). This orientation is relevant to define contact tools, since the material of the tool must be on the right hand side when following the list of Curves.

The orientation is also relevant when meshing a Side, since the Wire must be defined “area to the left”. If the Wire is made of only one Curve, the orientation of the Wire is set to the one of this Curve. If the Wire is made of two Curves, the first Curve defines the Wire orientation.

The Wire can be defined by specifying all its Curves at once, but it is always possible to add more Curves with the push() member function:

wire = wirset.add( Wire(number, [curve1, curve2, curve3, ...]) )
wire.push(curve4)
wire.push([curve5, curve6,...])
 number Wire user number ($\ge 1$) curve1, curve2, curve3, … List of Curves

## Notes about Wires and contact

• When a Wire is used as a contact tool, the succession of Curves should have a continuous normal.
• If it is not the case, MultiProjWire (same definition syntax) can handle multiple projections when the normal is not continuous.
• For rigid-deformable contact, a Wire must be defined “area to the left”, and the Wire orientation if defined by the succession of its curves.
• The function wire.reverse() inverts the order of definition of the wire, which also inverts the orientation of its normal.
• To understand how Metafor computes an “average out-of-plane normal” of a Wire, which is sometimes used in 3D contact, read Surfaces.