Electrical

Walter Frei | April 2, 2013

A question that comes up occasionally is whether or not you can compute the inductance of a single straight wire. This seemingly simple question actually does not really have an answer, and gives us the opportunity to talk about a very interesting point when solving Maxwell’s equations. Anybody working in the field of computational electromagnetics should have an understanding of this key concept, as it will help you properly set up and interpret models involving magnetic fields.

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Fanny Littmarck | April 1, 2013

In the world of bearings, there are many different types to choose from. For certain applications, magnetic bearings trump their mechanical counterparts in several regards. In order to understand how the bearing will perform, using a simulation tool to calculate design parameters is a good idea.

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Fanny Littmarck | March 29, 2013

Smart materials are able to convert one form of energy to another. These materials can be either solid or fluid, and are typically located within what’s called a smart structure. What makes these materials and structures so “smart”? Let’s find out.

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Daniel Smith | March 27, 2013

In a previous blog entry I discussed some of the exotic properties of graphene. The fact that graphene consists of a single layer of atoms means the aspect ratio of any graphene-based structure may be very high. High aspect geometries present their own array of modeling challenges.

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Fanny Littmarck | March 4, 2013

Last week you saw how you can simulate the heating of a car’s brake discs. This reminded me of another type of brake — the eddy current brake (also known as magnetic brake). Whereas the other model was a study in heat transfer, eddy current brakes deal with electromagnetics.

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Phil Kinnane | February 22, 2013

“The Bumblebee Flies Anyway” was a book by Robert Cormier that I read as a young teenager. In it, Cormier describes how bumblebees are natural anomalies as they seemingly do not have the aerodynamic capability to actually fly. Their wing span and flapping speed should not provide enough lift to allow flying, and this is a fact that I have always associated with bumblebees since. Yet, this has been proven not to be true, as a closer investigation of the […]

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Andrew Griesmer | February 20, 2013

The electrical grid describes the network created for producing electricity, transmitting it and delivering it to the consumers. A “smart grid” is an electrical grid that gathers information on the suppliers and consumers automatically to improve efficiency and sustainability in the system. As the automated technology improves, the hardware that physically connects the electrical grid together must improve as well. This hardware, the “nuts and bolts” of the grid, is comprised of transformers, cable joints, terminations, bushings, and fault current […]

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Andrew Griesmer | February 18, 2013

Induction occurs when a metal object moves in the presence of a magnetic field inducing a current in that object. The induced current causes it to heat up (called inductive heating), as all current does. Yet, simulating these two coupled physics together can be difficult to do as they are intrinsically based on different time scales. COMSOL Multiphysics is able to cleverly simulate them through combining the frequency domain modeling of the magnetic field with a stationary simulation of the […]

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Phil Kinnane | February 6, 2013

In its natural state, air is a good insulator. However, if it’s adequately ionized, it can ultimately lead to “corona discharge”. What does that mean and why is it important? Let’s find out.

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Fanny Littmarck | January 29, 2013

One of the classic multiphysics couplings in engineering and science is Joule heating, also called resistive heating or ohmic heating. Some Joule heating examples include heating of conductors in electronics, fuses, electric heaters, and power lines. When a structure is heated by electric currents, the device can reach high temperatures and either structurally degenerate or even melt. The design challenge is to remove this heat as effectively as possible. COMSOL eases these challenges by providing a specialized multiphysics interface for […]

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Fanny Littmarck | December 12, 2012

A while back, I wrote about permanent magnet generators and how they generate electricity upon being set in motion. When browsing the papers from our conference in Bangalore, one on the topic of ultrasonic micro motors caught my eye. These motors are electromechanical in nature and instead initiate motion with the application of an electric voltage. Furthermore, these motors are miniaturized to fit a micro-scale environment.

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