Material and nonlocal barrier records

Material type records

These records describe the material models.

Record syntax

MaterialType num (in) d (rn)

The order of the records is arbitrary and the material number is given by num. The numbering must start at one and end at n, where n is the number of records.

Parameters

d (rn)

Material density. Compulsory for every material model.

Note

The available material models, their formulation and their own parameters are documented in the separate Material Library Manual. This section covers only what is common to every material record.

Nonlocal barrier records

Nonlocal material models of the integral type replace a suitable local quantity in the local constitutive law by its nonlocal counterpart, obtained as a weighted average over some characteristic volume. The weighted average is a sum of the remote value multiplied by the value of a weight function, which typically depends on the distance between the remote and the receiver point and decreases as that distance grows.

Sometimes the mutual interaction between two points has to be disregarded — for example when they lie on opposite sides of a thin notch, which prevents the nonlocal interaction from taking place. Barriers are the way to introduce such a constraint. A barrier is a curve in 2D or a surface in 3D; when the line connecting the receiver and the remote point intersects a barrier, the barrier is activated and the corresponding interaction is not taken into account.

The number of barrier records is declared by nbarrier in the Components size record.

Polyline barrier

A polyline barrier for 2D problems, defined as a sequence of nodes representing its vertices.

Record syntax

polylinebarrier num (in) vertexnodes (ia) [xcoordindx (in)] [ycoordindx (in)]

Parameters

vertexnodes (ia)

Numbers of the nodes representing the polyline vertices.

[xcoordindx (in)], [ycoordindx (in)]

Select the plane — xy, yz or xz — in which the barrier is defined. xcoordindx is the first coordinate index and ycoordindx the second. The defaults are 1 and 2, giving a barrier in the xy plane.

Symmetry barrier

An implementation of a symmetry barrier, allowing up to three mutually orthogonal planes of symmetry. It models the symmetry of the averaged field on the boundary without the other part of the structure across the plane of symmetry having to be modelled, by modifying the integration weights of the source points to account for the symmetry.

The potential symmetry planes are given by an orthogonal, right-handed coordinate system whose axes are the normals of the corresponding symmetry planes.

Record syntax

symmetrybarrier num (in) origin (ra) normals (ra) activemask (ia)

Parameters

origin (ra)

Origin of the coordinate system.

normals (ra)

Three components of the x-axis direction vector followed by three components of the y-axis direction vector, both in the global coordinate system. The z-axis follows from the orthogonality conditions.

activemask (ia)

Which symmetry planes are active. The i-th nonzero value activates the symmetry barrier for the plane whose normal is the corresponding coordinate axis: x = 1, y = 2, z = 3.