Parts and Instances

The Parts and Instances functionality can be used to combine independently created substructures (or, parts) into a single model.

This feature allows greater flexibility in the creation of a finite element model. By following a few simple numbering requirements, you can define independent substructures which in turn can be easily combined into a final bigger model using simple translational and rotational transformations. Explicit instancing of parts can be achieved, as explained in the Instances section. This functionality is available for all analysis solution sequences and is currently not supported for optimization runs. OptiStruct-Multibody Dynamics (OS-MBD) and Geometric Nonlinear Analysis are not supported.

Motivation

There are various advantages to defining a large finite element model as a combination of substructures or parts:
  1. Model complexity is reduced as the structure is segregated into manageable substructures which are interconnected using simple transformations.
  2. Individual part modules can be locally updated without having to make cascading edits to the entire structure.


    Figure 1. Illustration of a Model Created as a Combination of Multiple Parts (substructures)
  3. Each substructure can be independently developed in a modular environment and later assembled into a single structure. This allows various departments working on a project to focus on independent modules, while following a few simple numbering requirements.

Numbering Requirements

In this implementation, specific ID control for grid points and elements (including rigid elements) is not required. Refer to ID Resolution Guidelines for a detailed explanation of part numbering and how this influences the various other data entries in the model. The following simple numbering requirements should be enforced for any solver deck containing multiple parts:

  1. Entities which are part specific, like grid points and elements, are numbered by part based local numbering.
  2. Global entities such as properties, materials, loads and boundary conditions are defined in the global numbering system.
  3. The individual parts forming the total structure can be combined without any changes in format if the numbering requirements (1) and (2) are met.