/// <summary>
/// Gets the global equivalent nodal loads for <see cref="Tetrahedral"/> element.
/// </summary>
/// <param name="elm">The elm.</param>
/// <returns>global equivalent nodal loads for <see cref="Tetrahedral"/> element</returns>
private Force[] GetGlobalEquivalentNodalLoads(Tetrahedral elm)
{
//p.263 of Structural Analysis with the Finite Element Method Linear Statics, ISBN: 978-1-4020-8733-2
//formula (8.37c) : the total body force is distributed in equal parts between the four nodes, as expected!
elm.UpdateGeoMatrix();
var v = elm.det / 6;
var f = new Force();
f.Fx = v / 4 * _vx;
f.Fy = v / 4 * _vy;
f.Fz = v / 4 * _vz;
return(new[] { f, f, f, f });
}
