private static void TestTrussShapeFunction()
{
var bar = new BarElement(3);
bar.Nodes[0] = new Node(0, 0, 0);
bar.Nodes[1] = new Node(1, 0, 0);
bar.Nodes[2] = new Node(2, 0, 0);
bar.Material = UniformIsotropicMaterial.CreateFromYoungPoisson(3, 0.3);
bar.Section = new Sections.UniformParametric1DSection(4);
var hlp = new TrussHelper(bar);
var pl = hlp.GetN_i(bar, 0);
hlp.GetJMatrixAt(bar, 0);
var stf = hlp.CalcLocalStiffnessMatrix(bar);
}
public void LoadInternalForce_concentratedLLoad_truss_Fx()
{
//internal force of 2 node truss with concentrated load and both ends fixed
var w = 2.0;
var forceLocation = 0.5; //[m]
var L = 4; //[m]
//var model = new Model();
var nodes = new Node[2];
nodes[0] = (new Node(0, 0, 0)
{
Label = "n0"
});
nodes[1] = (new Node(4, 0, 0)
{
Label = "n1"
});
var elm = new BarElement(nodes[0], nodes[1])
{
Label = "e0"
};
var u1 = new Loads.ConcentratedLoad();
u1.Case = LoadCase.DefaultLoadCase;
u1.Force = new Force(w, 0, 0, 0, 0, 0);
u1.CoordinationSystem = CoordinationSystem.Global;
u1.ForceIsoLocation = new IsoPoint(elm.LocalCoordsToIsoCoords(forceLocation)[0]);
var hlpr = new TrussHelper(elm);
var length = (elm.Nodes[1].Location - elm.Nodes[0].Location).Length;
foreach (var x in CalcUtil.Divide(length, 10))
{
var xi = elm.LocalCoordsToIsoCoords(x);
var mi = 0.0;
var vi = 0.0;
{
//https://www.amesweb.info/Beam/Fixed-Fixed-Beam-Bending-Moment.aspx
var a = forceLocation;
var b = L - a;
var ra = (1 - (a / L)) * w;
var rb = (1 - (b / L)) * w;
mi = ra + ((x > forceLocation) ? -w : 0.0);
}
var ends = hlpr.GetLocalEquivalentNodalLoads(elm, u1);
var testFrc = hlpr.GetLoadInternalForceAt(elm, u1, new double[] { xi[0] * (1 - 1e-9) });
var exactFrc = new Force(fx: mi, fy: 0, fz: vi, mx: 0, my: 0, mz: 0);
var df = testFrc.FirstOrDefault(i => i.Item1 == DoF.Dx).Item2 + exactFrc.Fx;
Assert.IsTrue(Math.Abs(df) < 1e-5, "invalid value");
}
{
var end1 = hlpr.GetLocalEquivalentNodalLoads(elm, u1);
var f0 = hlpr.GetLoadInternalForceAt(elm, u1, new double[] { -1 + 1e-9 }).ToForce();;
var sum = end1[0] + f0;
Assert.IsTrue(Math.Abs(sum.Forces.Length) < 1e-5, "invalid value");
Assert.IsTrue(Math.Abs(sum.Moments.Length) < 1e-5, "invalid value");
}
}
