Samcef element quality checks (Simcenter Samcef)

In Simcenter Samcef, you can use the Element Quality dialog box to specify options to perform system checks. These checks determine whether the element’s geometry is adequate for finite element matrix generation.

General geometric checks

The General Geometry Checks options in the Element Quality dialog box let you check the elements in your model for general element quality issues.

Check	Description
Minimum Element Edge Size <	Check element edge sizes smaller than a given tolerance.
Maximum Element Edge Size >	Check element edge sizes greater than a given tolerance.
2D Element Area <=	Check 2D element area.
3D Element Volume <=	Check 3D element volumes.
Tet Collapse	Searches for tetrahedral elements that have a volume that is close to zero. When you select the Tet Collapse check box, the software calculates the ratio of the height of a vertex to the square root of the area of the opposing face. This value approaches zero as the volume of the element approaches zero.

For more information on geometry checks, see Solver neutral element quality checks.

Solver-specific geometric checks: classical elements

Check	Description
Jacobian Sign	Checks the sign (positive or negative) of the Jacobian determinant at the element’s Gauss points. The sign of the Jacobian determinant for solid elements must be either consistently positive or consistently negative. If the sign is inconsistent, then the element fails the check.
Axisymmetric Consistent Y	When axisymmetric elements are modeled in the XZ plane, this check ensures that the nodes all lie in the same Y-plane within a tolerance.
Axisymmetric Consistent +X	When axisymmetric elements are modeled in the XZ plane, this check ensures that the X location for all nodes is ≥ 0.0.
Jacobian Ratio	Checks the ratio of the largest Jacobian determinant to the smallest. This ratio gives you an idea of overall distortion in an element. You can use the Jacobian Ratio check to identify when an element’s interior corner angles deviate too much from 90°. A Jacobian ratio close or equal to 1.0 is desired.
Jacobian Zero	Calculates the minimum value for the determinant of the Jacobian at all integration points for each element. A well-formed element has a positive Jacobian determinant at each Gauss point. The Jacobian determinant approaches zero as an element vertex angle approaches 180°.
Aspect ratio	Measures the ratio of the longest element edge to the shortest element edge.
Cohesive ratio	T is the biggest absolute distance between pair of opposite nodes and :For hexahedron-based cohesive elements, d1 and d2 are the lengths of the diagonals.For wedge based cohesive elements, d1 is the length of the 1st edge of the triangular face (1-2 in the element topology above), while d2 is the length of the 2nd edge (2-3).The software calculates the quality ratio as 2*T/(d1+d2). In general a ratio under 0.01 indicates a good shaped cohesive element.
Skew angle	The software creates lines between the midpoints of opposite sides of the element and then measures the angles between these lines. The angle with the greatest deviation from the ideal value is used to determine skew.
Minimum interior angle	Measures the minimum interior angle of the element.
Maximum interior angle	Measures the maximum interior angle of the element.
Taper	Measures the amount of geometric deviation of a quadrilateral element from a rectangular shape.
Quad	Measures the out-of-plane deviation of quadrangular element.
Solid	Measures the out-of-plane deviation of faces of solid element.

If you select the Use Element Type Specific Values option in the Element Quality dialog box, you can define specific check values for the different types of elements in the model.

Where do I find it?

Application	Pre/Post
Prerequisite	A FEM, assembly FEM, or Simulation file as the work and displayed part, with Simcenter Samcef as the specified solver
Command Finder	Element Quality
Menu	Analysis→Finite Element Model Check→Element Quality

Simcenter Samcef Element Quality Check customer defaults

Menu	Files→Utilities→Customer Defaults
Location in dialog box	Simulation→Pre/Post→Element Quality Check - Samcef

Learn more

Evaluating element quality

Correcting 2D element quality failures

General geometry checks for elements

Solver neutral element quality checks

Nastran and Multiphysicselement quality checks

Abaqus element quality checks

ANSYS element quality checks

LS-DYNA element quality checks

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Samcef element quality checks (Simcenter Samcef), Simcenter 3D 2021.1 Series

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