Defining Laminate Coordinate System
The next step is to define a coordinate system for the composite laminate in which the stacking sequence is interpreted. You can either customize the default Boundary System or add a new instances of boundary systems under the Definitions node within a component. Select the coordinate system in the Layered Material Link node.
In order to create a suitable laminate coordinate system using the Boundary System node,
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Define an appropriate direction from which first tangent direction of the coordinate system is obtained
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Reverse the normal direction if needed
Some examples of laminate coordinate systems in a cylindrical composite laminate, using different Boundary System settings, are given below.
Example 1
The first axis of the laminate coordinate system is aligned with the global x direction. This can be created by setting the Create first tangent direction from option to Global Cartesian (spatial) and Axis to x.
Figure 3-9: Example of a laminate coordinate system when the first axis is aligned with the global x direction.
Example 2
The first axis of the laminate coordinate system is at 45° to the global x direction. This can be created by first defining a Cylindrical System having Longitudinal axis as x-axis and then setting the Create first tangent direction from to Cylindrical System and Axis to Manual with {0,-1,1} as orientation.
Figure 3-10: Example of a laminate coordinate system when the first axis is at 45° to the global x direction.
Example 3
The first axis of laminate coordinate system is aligned with the global x direction but with the normal direction is pointing inward. This coordinate system can be created in a same way as in the first example. In addition to that, the Reverse Normal direction option is selected in the Boundary System node in order to point the normal vector inward.
Figure 3-11: Example of a laminate coordinate system where the first axis is aligned with the global x direction and the normal vector is pointing outward and inward respectively.
Note that it is also possible to reverse the normal direction only on some selected boundaries by using the Reverse Normal subnode on the Boundary System node.
In the COMSOL Multiphysics Reference Manual:
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Layered Material Link
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Boundary System