CAE Modeling Case Studies

Finite Element Model

Finite Element Model

Customer Modeling Requirements
Rail parts meshed at 6mm average element size.
Typical BIW components are meshed with a 10.0mm element average length. However, as this model is shared amongst multiple load cases it is advised to mesh the critical load carrying rails with a refined mesh size. This approach allows critical areas such as crush initiators and strengthening beads to be captured thus optimizing a single model robust to handle multiple load cases.

Customer Modeling Requirements II
Areas of contact were modeled with matching meshes.

Scanned data (point cloud data) converted to STL format

STL data cleaned and prepared for converting triangle mesh into quad/tria mesh model

Final quad-tria shell mesh of average element size 10mm

Typical finite element meshing requires CAD data for best mesh quality results. Very often CAD data for the existing part is not available so it needs to be created from the scanned data. This CAD creation can be time consuming process. To avoid CAD creation for CAE analysis as a final product, STL format is directly converted to finite quad/tria shell element model. Mesh Model is then offset inbound by half thickness distance of the original scanned part. All element quality criteria's are met while elements are following the curvatures. Allowed Finite mesh to Scan data deviation is +-2mm.

Model Quality Required Values
    Aspect 85%<2:1
    (not < than 10) 95%<3:1
    Warpage 15 MAX
    Skewness 45 MAX
    Quad Angle Min. 45 MAX
    Quad Angle Max. 135 MAX
    Tria Angle Min. 20 MIN
    Tria Angle Max. 120 MAX
    Jacobian SHELLS Not < than 0.7
    Jacobian SOLIDS Not < than 0.5
    % Trias    7
    Total Number of Elements 1135
# of Quads 1086
# of Trias 49
Model Validation Normal Modes Analysis Six Rigid Body Mode
        First Mode at 25 HZ

Transmission Housing

Transmission Housing

Customer Modeling Request

Customer Modeling Requirements
Model       CVT Housing
Attribute       NVH
CAD data       Provided by customer as IGES files
Weld data       Provided by customer
Deliverable         Transmission housing constructed with solid and shell elements, correlated to measured weights for each component
Quality Requirements
Aspect       5:1
Warpage SHELL       10
Warpage SOLID       15
Skewness       45
Quad Angle Min.       45
Quad Angle Max.       135 (140-solids)
Tria Angle Min.       20
Tria Angle Max.       120
Jacobian       0.6
Min. Length       4 mm
Max. Length       15 mm
% Trias       > 5%
Model Construction
A combination of solid and shell elements were used to build the model. The weight of the finite element model was measured and correlated to the finite element model.

Model Delivery
  • Modeling validation sheet delivered with completed model.
  • 100% quality requirements met.
  • Validation run performed to ensure running model and parts attached properly (normal modes).

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