All posts by Walter Frei

Walter Frei | September 2, 2015

Modeling geometries with high aspect ratios can be one of the more challenging tasks for the finite element analyst. You want to have a mesh that will accurately represent the geometry and the solution, but you do not want too many elements, as solving your models would then require excessive computational resources. Here, we will look at using swept meshing to generate efficient and accurate finite element meshes in the context of some common modeling cases.

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Walter Frei | August 11, 2015

In the course of building multiphysics models, we often encounter situations in which the solution to one physics is periodic — or very nearly so — while the solutions to other physics of interest are nonperiodic. If we know this ahead of time, it is possible to exploit the periodicity to reduce computational requirements. Here, we will demonstrate how to accomplish this using the General Extrusion component couplings in COMSOL Multiphysics.

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Walter Frei | August 5, 2015

One useful — but in my experience, rarely used — capability available within COMSOL Multiphysics is the ability to compute design sensitivities. Assuming that you have a single objective function that is computed based on your finite element model, you can easily compute how sensitive this objective function is with respect to any model input, using only the core COMSOL Multiphysics package. In this blog post, we will look at how to use this functionality.

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Walter Frei | July 21, 2015

When modeling a manufacturing process, such as the heating of an object, it is possible for irreversible damage to occur due to a change in temperature. This may even be a desired step in the process. With the Previous Solution operator, we can model such damage in COMSOL Multiphysics. Here, we will look at the “baking off” of a thin coating on a wafer heated by a laser.

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Walter Frei | June 30, 2015

Over the last several weeks, we’ve published a series of blog posts addressing the various domain and boundary conditions available for wave electromagnetics simulation in the frequency domain; as well as modeling, meshing, and solving options. In this blog post, I will tie all of this information together and provide an introduction to the various types of problems that you can solve in the RF and Wave Optics modules.

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Walter Frei | June 25, 2015

COMSOL Multiphysics version 5.1 includes a Previous Solution operator within time-dependent studies. This operator allows you to evaluate quantities at the previous time step when using the default implicit time-stepping algorithm. Let us take a look at how this operator is implemented and then examine how it can be used for various modeling needs.

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Walter Frei | June 22, 2015

A question that we are asked all of the time is if COMSOL Multiphysics can model laser-material interactions and heating. The answer, of course, depends on exactly what type of problem you want to solve, as different modeling techniques are appropriate for different problems. Today, we will discuss various approaches for simulating the heating of materials illuminated by laser light.

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Walter Frei | June 18, 2015

When solving wave electromagnetics problems with either the RF or Wave Optics modules, we use the finite element method to solve the governing Maxwell’s equations. In this blog post, we will look at the various modeling, meshing, solving, and postprocessing options available to you and when you should use them.

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Walter Frei | June 2, 2015

The COMSOL Conference is a great way for those in the simulation community to learn about COMSOL Multiphysics® software and its family of products. This year’s multiphysics simulation event will feature a variety of new learning opportunities for conference attendees. See what’s on the schedule for the COMSOL Conference 2015 at its first two stops — Boston and Grenoble.

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Walter Frei | May 27, 2015

Whenever we are solving a wave electromagnetics problem in COMSOL Multiphysics, we build a model that is composed of domains and boundary conditions. Within the domains, we use various material models to represent a wide range of substances. However, from a mathematical point of view, all of these different materials end up being handled identically within the governing equation. Let’s take a look at these various material models and discuss when to use them.

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Walter Frei | May 14, 2015

Metals are materials that are highly conductive and reflect an incident electromagnetic wave — light, microwaves, and radio waves — very well. When using the RF Module or the Wave Optics Module to simulate electromagnetics problems in the frequency domain, there are several options for modeling metallic objects. Here, we will look at the Impedance and Transition boundary conditions as well as the Perfect Electric Conductor boundary condition, offering guidance on when to use each one.

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