public void LoadInternalForce_uniformload_truss()
{
//internal force of 2 node beam beam with uniform load and both ends fixed
var w = 2.0;
var nodes = new Node[2];
var l = 4;
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.UniformLoad(LoadCase.DefaultLoadCase, Vector.I, w, CoordinationSystem.Global);
var hlpr = new ElementHelpers.TrussHelper(elm);
for (var x = 0.0 + 1e-6; x <= l - 1e-6; x += 0.1)
{
var local = x;
var iso = elm.LocalCoordsToIsoCoords(x);
var test = hlpr.GetLoadInternalForceAt(elm, u1, iso).FirstOrDefault(i => i.Item1 == DoF.Dx).Item2;
var exact = (w * l - x * l) / 2.0;
Assert.IsTrue(test.FEquals(exact, 1e-5), "invalid value");
}
}
public void LoadEquivalentNodalLoads_uniformload_truss()
{
//internal force of 2 node beam beam with uniform load and both ends fixed
var w = 2.0;
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.UniformLoad(LoadCase.DefaultLoadCase, -Vector.I, w, CoordinationSystem.Global);
var hlpr = new ElementHelpers.TrussHelper(elm);
var loads = hlpr.GetLocalEquivalentNodalLoads(elm, u1);
var L = (elm.Nodes[1].Location - elm.Nodes[0].Location).Length;
var f1 = -w * L / 2;
var f2 = -w * L / 2;
Assert.IsTrue(Math.Abs(loads[0].Fx - f1) < 1e-5, "invalid value");
Assert.IsTrue(Math.Abs(loads[1].Fx - f2) < 1e-5, "invalid value");
}
