A task road map helps you visualize the sequencing of tasks. Having a clear focus on the simulation tasks at hand will help you be more productive and efficient in learning Patran.

Each of the three stages shown in the figure above represents a fundamental part of the simulation process. Within each stage is a set of tasks executed in different parts of Patran.

This stage is typically the most time intensive. The simulation or model must describe the shape and size of the product, detail what materials are used to construct the product, stipulate how the product is assembled, and define the environmental forces that the product endures. The majority of the tools in Patran help you construct this product design model.

Patran provides its own set of tools for geometry creation and editing. Using these tools, you can quickly create parts with two- and three-dimensional wireframe, surface, and solid geometry. The Geometry application form provides over a hundred options for creating basic geometric objects, as well as numerous editing and verification functions. Patran’s CAD interface also lets you import and edit CAD data from many leading CAD programs.

Once you have imported or created the geometry, you can create and verify the finite element mesh using a powerful suite of meshing tools. These tools include the industry leading automeshers for curves, surfaces, and solids, as well as mapped meshing and paved surface meshing. Additionally, you can edit the analysis model interactively.

The Materials application is where you define the materials for your analysis model. A material model is a group of material properties that describe what your model is made of (such as steel or a composite) and the attributes of that material (stiffness, density, and so on). Once you define the materials for your model, you will assign them to model regions.

The finite element analysis tests a particular model’s reaction to particular loads and constraints imposed as boundary conditions. Loads are environmental factors such as force, pressure, temperature, and voltage. Boundary conditions are described in terms of degrees-of-freedom, that are the directions in which the edges of the model are free to move in 3D space, along a translational (straight-line) or a rotational path.

Once you have completed the product design model, the analysis stage of the simulation project begins.There are several options for running a finite element analysis using Patran. You may choose from one of MSC’s analysis codes, an outside commercial code, or an in-house proprietary code. In each case you will need to complete several tasks in Patran to format and setup the analysis.

You initially select an analysis code when you begin each simulation project. Patran assumes that you are using a single analysis code. As you build the product design model, Patran stores the information using the formats and naming conventions of the analysis code. At any time during the project you can change the analysis code. When you change the code selection Patran attempts to convert all of the data into the new format.

You will need to define element types (such as beam, shell, and so on) and element-related properties for regions of your model, then assign these definitions to geometric or FEM entities. Element type selection is based on the finite element code, the dimensions of the model, and your assumptions about the model’s behavior. Additional properties describe attributes such as the thickness of a plate, the spring constant for a spring, an area for a bar element, materials, and so on.

The Analysis application provides the link between the Patran environment and the analysis solvers. These solvers can include MSC analysis codes, other commercially available solvers, or proprietary codes developed by analysts for their own exclusive use. The Analysis application provides the means to:

Finite element results generated in the second stage of the project generally take the form of numbers, such as the amount of displacement at a point in the model. However, it is difficult to gain a real understanding of how a model behaves by looking at a stack of numbers on paper. The third stage of the simulation project entails using Patran’s ability to visualize results using computer graphics, animation, and other results tools.

Patran is state-of-the-art in its ability to display, sort, combine, scale, and query in a general way a single results database. After execution, analysis results are loaded directly into the Patran relational database and can be sorted by time step, frequency, temperature, or spatial location.

A standard simulation project carried out from start to finish would typically follow the sequence of tasks outlined above. However, it is important to point out that this task sequence is a generalization. In reality, each simulation project is unique with a distinct set of requirements, resources, data, and assumptions. These factors dictate both the tasks and the sequence.

Within the simulation process there is an inherent feedback loop. Results or problems encountered in one stage of the project may prompt you to go back and change or re-examine a previous stage. Analysis results that exceed requirements often drive model design changes.

Within each stage the sequence in which you perform the tasks may change. For example, you may choose to model the materials in your model once the geometry model is complete or you may elect to wait until after the meshing is done. This depends on whether you plan to define the materials according geometrical regions or on an element-by-element basis.

As you learn to use Patran, keep in mind that the task sequences are flexible to a certain degree. For each project that you begin, you will have to evaluate the requirements, resources, and data, to develop a
task plan.