Structural & Acoustics Blog Posts
Specific Absorption Rate (SAR) in the Human Brain
It seems everyone and their kid brother has a cell phone these days — and we are constantly using them. We don’t just rely on them to make calls anymore, either; they serve as our maps, calendars, to-do lists, channel for social interaction, and so forth. This continuous use begs the question: “What about the radiation our phones emit, and how much of it is absorbed by our brains?” When considering this, scientists use the specific absorption rate (SAR) to […]
Turbine Stator Blade Cooling and Aircraft Engines
Technology and mechanics enthusiasts might agree that engines are very cool — and they also know how fussy they get when running into cooling problems. When it comes to aircraft propulsion, overheating is not an option. Most planes can’t fly safely without an engine, so why run the risk of overheating? While current engine designs limit that risk using clever cooling systems, another path to solve this problem would be to design more energy-efficient engines, exempt from excessive heat release. […]
Simulating the Freeze-Drying Process
When thinking about freeze-drying processes, I am reminded of astronaut food like the freeze-dried ice cream I tried as a kid. While this application of freeze-drying is important for preserving food being launched into space, there is also an incredible number of noteworthy applications that are used a little closer to home. Let’s take a look at the freeze-drying process, how it can be simulated, and some of the products and designs that rely on it to function.
Analyzing Electrical and Thermal Conductance in a Contact Switch
A contact switch is used to regulate whether or not an electrical current is passing from a power source and into an electrical device. These switches are found in many types of equipment and they are used to control, for example, the power output from a wall socket into a device when it is plugged in; the currents passing across the circuit board of a computer; or the electricity powering a light bulb when the switch is flipped on. Because of their […]
Fatigue Prediction Using Critical Plane Methods
Research on fatigue started in the 19th century, initiated following failing railroad axles that caused train accidents. In a rotating axle, stress varies from tension to compression and back to tension in one revolution. The load history is simple because it is uniaxial and proportional. Fatigue can then be evaluated with the S-N curve, also known as the Wöhler curve, which relates stress amplitude to a component’s life. In many applications we deal with multiaxiality and non-proportional loading. In this […]
Acoustics Tutorial for Modeling Organ Pipe Design
The way the sound is shaped as it passes through the pipe of an organ is the result of a carefully calculated and intricate pipe design. Browsing through the Model Gallery, I came across a model of an organ pipe, and it happens to be a great acoustics tutorial for using the Pipe Acoustics, Frequency Domain interface in COMSOL Multiphysics. Let’s talk organ pipe design, and walk through how we can model it with multiphysics software.
Can You Use Heat Transfer to Predict Migration of Contaminants?
The flow of fluid through a porous medium is usually described by Darcy’s Law. However, what if you wanted to look at a combination of fluid flow, heat transfer, and mass transport in a porous medium? Instead of using Darcy’s Law, which calculates an average linear velocity for fluid flow in porous media, the Navier-Stokes equations would be necessary in order to obtain accurate results. In addition, heat convection and conduction, as well as mass transport would need to be […]
Simulating an Engine Governor, the Spring Loaded Centrifugal Governor
We’ve probably all seen centrifugal force in action in one way or another, whether it be riding on a merry-go-round as a child, spinning a bucket of water upside and observing as the contents hug the insides of the bucket, or watching mud spinning off of a turning tire. In addition to making dizzying carnival rides, this force can be used in the design of many mechanical applications, where it is harnessed to control a variety of effects. One such […]