private void FindBodyAndTipNodesAndElements(HashSet <XNode> bodyNodes, HashSet <XNode> tipNodes,
List <XContinuumElement2D> tipElements)
{
foreach (var element in Mesh.Elements)
{
element.EnrichmentItems.Clear();
ElementEnrichmentType type = CharacterizeElementEnrichment(element);
if (type == ElementEnrichmentType.Tip)
{
tipElements.Add(element);
foreach (var node in element.Nodes)
{
tipNodes.Add(node);
}
element.EnrichmentItems.Add(CrackTipEnrichments);
}
else if (type == ElementEnrichmentType.Heaviside)
{
foreach (var node in element.Nodes)
{
bodyNodes.Add(node);
}
// Cut elements next to tip elements, they will be enriched with both Heaviside and tip functions. If all
// nodes were enriched with tip functions, the element would not be enriched with Heaviside, but then it
// would be a tip element and not fall under this case.
element.EnrichmentItems.Add(CrackBodyEnrichment);
}
}
foreach (var node in tipNodes)
{
bodyNodes.Remove(node); // tip element's nodes are not enriched with Heaviside
}
ReportTipElements(tipElements);
}
// Warning: TipElements must first be cleared in this iteration
private void FindBodyAndTipNodesAndElements(HashSet <XNode> bodyNodes, HashSet <XNode> tipNodes)
{
var bothElements = new HashSet <XContinuumElement2D>();
foreach (var element in Mesh.Elements)
{
element.EnrichmentItems.Clear();
ElementEnrichmentType type = CharacterizeElementEnrichment(element);
if (type == ElementEnrichmentType.Tip)
{
tipElements.Add(element);
foreach (var node in element.Nodes)
{
tipNodes.Add(node);
}
element.EnrichmentItems.Add(CrackTipEnrichments);
}
else if (type == ElementEnrichmentType.Heaviside)
{
foreach (var node in element.Nodes)
{
bodyNodes.Add(node);
}
element.EnrichmentItems.Add(CrackBodyEnrichment);
}
else if (type == ElementEnrichmentType.Both)
{
tipElements.Add(element);
bothElements.Add(element);
foreach (var node in element.Nodes)
{
tipNodes.Add(node);
bodyNodes.Add(node);
}
element.EnrichmentItems.Add(CrackTipEnrichments);
element.EnrichmentItems.Add(CrackBodyEnrichment);
}
}
// After all Heaviside nodes are aggregated remove the nodes of tip elements
foreach (var element in tipElements)
{
foreach (var node in element.Nodes)
{
bodyNodes.Remove(node);
}
}
foreach (var element in bothElements) // Re-adding these nodes afterwards is safer
{
foreach (var node in element.Nodes)
{
bodyNodes.Add(node);
}
}
ReportTipElements(tipElements);
}
public SortedSet <CartesianPoint> FindTriangleVertices(XContinuumElement2D element)
{
var triangleVertices = new SortedSet <CartesianPoint>(element.Nodes, pointComparer);
int nodesCount = element.Nodes.Count;
ElementEnrichmentType type = CharacterizeElementEnrichment(element);
if (type != ElementEnrichmentType.Standard)
{
// Find the intersections between element edges and the crack. TODO: See Serafeim's Msc Thesis for a correct procedure.
for (int i = 0; i < nodesCount; ++i)
{
XNode node1 = element.Nodes[i];
XNode node2 = element.Nodes[(i + 1) % nodesCount];
double levelSet1 = levelSetsBody[node1];
double levelSet2 = levelSetsBody[node2];
if (levelSet1 * levelSet2 < 0.0)
{
// The intersection point between these nodes can be found using the linear interpolation, see
// Sukumar 2001
double k = -levelSet1 / (levelSet2 - levelSet1);
double x = node1.X + k * (node2.X - node1.X);
double y = node1.Y + k * (node2.Y - node1.Y);
// TODO: For the tip element one intersection point is on the crack extension and does not
// need to be added. It is not wrong though.
triangleVertices.Add(new CartesianPoint(x, y));
}
else if (levelSet1 == 0.0)
{
triangleVertices.Add(node1); // TODO: perhaps some tolerance is needed.
}
else if (levelSet2 == 0.0)
{
triangleVertices.Add(node2);
}
}
if (type == ElementEnrichmentType.Tip)
{
triangleVertices.Add(crackTip);
}
}
return(triangleVertices);
}
