Model Builder

Operations, Sequences, and Selections

The core COMSOL Multiphysics^® package provides geometry modeling tools for creating parts using solid objects, surfaces, curves, and Boolean operations. Geometries are defined by sequences of operations, where each operation is able to receive input parameters for easy edits and parametric studies in multiphysics models. The connection between the geometry definition and defined physics settings is fully associative — a change in the geometry will automatically propagate related changes throughout the associated model settings.

Geometric entities such as material domains and surfaces can be grouped into selections for subsequent use in physics definitions, meshing, and plotting. Additionally, a sequence of operations can be used to create a parametric geometry part, including its selections, which can then be stored in a Part Library for reuse in multiple models.

Import, Repair, Defeature, and Virtual Operations

The import of all standard CAD and ECAD files into COMSOL Multiphysics^® is supported by the CAD Import Module and ECAD Import Module, respectively. The Design Module further extends the available geometry operations in COMSOL Multiphysics^®. Both the CAD Import Module and the Design Module provide the ability to repair and defeature geometries. Surface mesh models, such as in the STL format, can also be imported and then converted to a geometry object by the COMSOL Multiphysics^® core package. Import operations are like any other operation in the geometry sequence and can be used with selections and associativity for performing parametric and optimization studies.

As an alternative to the defeature and repair capabilities of the COMSOL^® software, so-called virtual operations are also supported to eliminate the impact of artifacts on the mesh, such as sliver and small faces, which do not add to the accuracy of the simulation. Unlike the defeaturing tools, virtual operations do not change the curvature or fidelity of the geometry, while yielding a cleaner mesh.

Transparency and Flexibility via Equation-Based Modeling

To really be useful for scientific and engineering studies and innovation, a software has to allow for more than just a hardwired environment. It should be possible to provide and customize model definitions based on mathematical equations directly in the user interface. The COMSOL Multiphysics^® software offers this level of flexibility with its built-in equation interpreter that can interpret expressions, equations, and other mathematical descriptions on the fly before it generates a numerical model. Adding and customizing expressions in the physics interfaces allows for freely coupling them with each other in order to simulate multiphysics phenomena.

The capabilities for customization go even further. With the Physics Builder, it is also possible to use custom equations to create new physics interfaces for easy access and manipulation when they are to be included in future models or shared with colleagues.

Study or Analysis Types

When a physics interface is selected, a number of different studies (analysis types) are suggested by COMSOL Multiphysics^®. For example, for solid mechanics analyses, the software suggests time-dependent, stationary, or eigenfrequency studies; for CFD problems, the software would only suggest time-dependent and stationary studies. Other study types can also be freely selected for any type of analysis. Study step sequences structure the solution process in order to enable users to select the model variables for which they want to solve in each study step. The solution from any of the previous study steps can be used as input to a subsequent study step.

Sweeps, Optimization, and Estimations

Any study step can be run with a parametric sweep, which can include one or multiple parameters in a model, from geometry parameters to settings in the physics definitions. Sweeps can also be performed using different materials and their defined properties, as well as over lists of defined functions.

Using the Optimization Module, optimization studies for topology optimization, shape optimization, or parameter estimations based on a multiphysics model can be performed. COMSOL Multiphysics^® offers both gradient-free and gradient-based methods for optimization. For parameter estimation, least-squares formulations and general optimization problem formulations are available. Built-in sensitivity studies are also available, where they compute the sensitivity of an objective function with respect to any parameter in the model.

Show off results to the world. COMSOL Multiphysics^® sports powerful visualization and evaluation tools so that results can be presented in a meaningful and polished manner. The built-in tools can be used or visualizations can be expanded with derived physical quantities by entering mathematical expressions into the software. Therefore, just about any quantity of interest related to simulation results can be visualized in COMSOL Multiphysics^®.

Visualization Capabilities

Visualization capabilities include surface, slice, isosurface, cut plane, arrow, and streamline plots, to name just a few plot types. A range of numerical postprocessing tools are available for evaluation of expressions, such as integrals and derivatives. The max, min, average, and integrated values of any quantity or derived quantities throughout volumes, on surfaces, along curved edges, and at points can be computed. Results evaluation tools specific to certain areas of engineering and science have also been included in many of the physics-based modules.

Exporting Results and Generating Reports with Other Software

Data can be exported and processed via third-party tools. Numerical results can be exported to text files on the .txt, .dat, and .csv formats as well as to the unstructured VTK format. With LiveLink™ for Excel^®, results can be exported to the Microsoft Excel^® spreadsheet software file format (.xlsx). Images can be exported to several common image formats, as well as the glTF™ file format for exporting 3D scenes. Animations can be exported in the WebM format and as animated GIF, Adobe Flash^® technology, or AVI files. Reports summarizing the entire simulation project can be exported to HTML (.htm, .html), Microsoft^® Word^® file format (.doc), or Microsoft^® PowerPoint^® fil e format (.pptx).