The two examples in this section demonstrate how to set up an equivalent beam model of a layered composite shell structure. ACP (Pre) is used to compute the equivalent sectional properties from the shell-based 3D composite models. This workflow is typically used for slender structures such as wind turbine blades or helicopter rotor blades to efficiently evaluate their dynamic behavior. In each example, the results of the beam model are compared with the 3D model. In both cases, the results are very similar, which shows the accuracy of the workflow.
The first example is a composites box with a constant cross section and laminate. The second example is a generic wind turbine blade where the cross section and the laminate vary along the longitudinal axis. Both have the same project schematic in the Workbench application as shown in Figure 4.62: Workflow of a Model Analysis with an Equivalent Beam Model. The top systems are used to configure the 3D model, which steps include:
Importing the shell geometry and meshing it in the Mechanical application (A4)
Defining the layup in ACP (Pre) (A5) and computing the equivalent beam properties
Preparing the APDL input for the beam model in the Modal: Beam model (C) system
Running the same analysis with the shell or solid model in the Modal Solid (B) system to compare the results with the equivalent beam model
The analysis with the equivalent beam model is configured in the Modal: Beam model (C) system. It contains the beam elements and the computed equivalent section properties from ACP (Pre) (A5) which are passed to the solver by an APDL Command snippet.
Important: Use the same unit system in ACP (Pre) (A5) and Modal: Beam model (C) to ensure that the computed beam properties have proper units.
