The following fields are needed to define the output for *ELEMENT_SHELL_COMPOSITE cards for the LS-DYNA application. The mapped orientations are given from the main axis of the orientation tensor corresponding to the largest eigenvalue. This enables modeling with any arbitrary orthotropic material law available in the LS-DYNA application. The thicknesses of the layers are equally spaced.
| NPLANE = INT |
1 - Reduced integrated shell elements 4 - Fully integrated shell elements |
| NTHICK = INT | Number of through-thickness integration points in the target mesh. |
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IntegrationRule = Gauss Lobatto Autoform Moldflow Eq Distr | Define the through-thickness integration rule for the mapping result. This option directly affects the positions of the through-thickness integration points on the target mesh. |
| MapStress = NO | Specify whether *INITIAL_STRESS_SHELL fields should be written. For the *ELEMENT_SHELL_COMPOSITE option, set this flag to NO. |
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Thck_Avg_Opt = Ele Avg Nodal Avg |
Thickness averaging option. When using *ELEMENT SHELL THICKNESS, nodes may hold different thickness information, depending on the element to which they belong. This is especially critical for components with ribs. With the default setting (Ele Avg), the Envyo application calculates through-thickness integration points using the nodal thicknesses stored on the element nodes by interpolating the resulting thicknesses at the in-plane integration points via shape functions, allowing for the correct calculation of the local through-thickness integration points. By choosing the Nodal Avg option, the application first collects all thicknesses stored on one node from its attached elements and averages these thicknesses. Interpolation to the in-plane integration points using shape functions is then performed. |
| MapMainDir = YES | Activate mapping of the main directions to *ELEMENT_SHELL_COMPOSITE fields. |
| TargetThickness = DOUBLE | Define the thickness of the target part. If a SectionFile is included in the source mesh, this value will be ignored. If the target mesh already has elements with thickness values, this option can be ignored. |
| Shell_Option = Composite | Activates the output of *ELEMENT_SHELL_COMPOSITE fields. |
Note: When using the MapMainDir=YES functionality, *ELEMENT_SHELL_COMPOSITE keyword cards are created. Since neither Gauss nor Lobatto integration rules can be reproduced using this keyword, regardless of the chosen integration point thickness, which is interpreted as weighting-factors in the LS-DYNA application, you should use an equal distribution of the integration points (IntegrationRule=Eq Distr). Integration points are assigned to the mid-point of the layer thickness defined in either *PART - or *ELEMENT_SHELL_COMPOSITE. When Gauss or Lobatto is set as the integration rule together with MapMainDir=YES, the weights calculated from the Legendre polynomial are used to calculate the integration point positions and corresponding thicknesses. The real relative integration point position would not be at ±1 (with Lobatto, for example), since this would lead to a zero thickness at the integration point, following the *ELEMENT_SHELL_COMPOSITE definition. This does not affect the integration point positions calculated using *INITIAL_STRESS_SHELL output for *MAT_157 or *MAT_215.