evaluate shape quality of mesh elements -凯发k8网页登录

evaluate the shape quality of the elements of a 3-d mesh.

create a pde model.

model = createpde;

include and plot the following geometry.

importgeometry(model,"platesquareholesolid.stl");
pdegplot(model)

create and plot a coarse mesh.

mesh = generatemesh(model,"hmax",35)

mesh = 
  femesh with properties:
             nodes: [3x487 double]
          elements: [10x213 double]
    maxelementsize: 35
    minelementsize: 17.5000
     meshgradation: 1.5000
    geometricorder: 'quadratic'

pdemesh(model)

evaluate the shape quality of all mesh elements. display the first five values.

q = meshquality(mesh);
q(1:5)

ans = 1×5
    0.3079    0.2917    0.6189    0.6688    0.5571

find the elements with the quality values less than 0.2.

elemids = find(q < 0.2);

highlight these elements in blue on the mesh plot.

pdemesh(mesh,"facealpha",0.5)
hold on
pdemesh(mesh.nodes,mesh.elements(:,elemids), ...
                  "facecolor","blue", ...
                  "edgecolor","blue")

plot the element quality in a histogram.

figure
hist(q)
xlabel("element shape quality","fontweight","b")
ylabel("number of elements","fontweight","b")

find the worst quality value.

qworst = min(q)

qworst = 0.1691

find the corresponding element ids.

elemids = find(q==qworst)

elemids = 1×2
    10   136

evaluate the shape quality of the elements of a 2-d mesh.

create a pde model.

model = createpde;

include and plot the following geometry.

importgeometry(model,"platesquareholeplanar.stl");
pdegplot(model)

create and plot a coarse mesh.

mesh = generatemesh(model,"hmax",20)

mesh = 
  femesh with properties:
             nodes: [2x286 double]
          elements: [6x126 double]
    maxelementsize: 20
    minelementsize: 10
     meshgradation: 1.5000
    geometricorder: 'quadratic'

pdemesh(model)

find the ids of the elements within a box enclosing the center of the plate.

elemids = findelements(mesh,"box",[25,75],[80,120]);

evaluate the shape quality of these elements. display the result as a column vector.

q = meshquality(mesh,elemids);
q.'

ans = 12×1
    0.2980
    0.8253
    0.2994
    0.6581
    0.7838
    0.6104
    0.3992
    0.6921
    0.2948
    0.5726
      ⋮

find the elements with the quality values less than 0.4.

elemids04 = elemids(q < 0.4)

elemids04 = 1×4
     9    19    69    83

highlight these elements in green on the mesh plot. zoom in to see the details.

pdemesh(mesh,"elementlabels","on")
hold on
pdemesh(mesh.nodes,mesh.elements(:,elemids04),"edgecolor","green")
zoom(10)

determine the shape quality of mesh elements by using the ratios of minimal to maximal dimensions.

create a pde model and include the l-shaped geometry.

model = createpde(1);
geometryfromedges(model,@lshapeg);

generate the default mesh for the geometry.

mesh = generatemesh(model);

view the mesh.

pdeplot(model)

evaluate the shape quality of mesh elements by using the minimal to maximal dimensions ratio. display the first five values.

q = meshquality(mesh,"aspect-ratio");
q(1:5)

ans = 1×5
    0.8339    0.7655    0.7755    0.8301    0.8969

evaluate the shape quality of mesh elements by using the default setting. display the first five values.

q = meshquality(mesh);
q(1:5)

ans = 1×5
    0.9837    0.9605    0.9654    0.9829    0.9913