## How to Evaluate Gear Mesh Stiffness in a Multibody Dynamics Model

##### Pawan Soami December 9, 2016

When performing a noise, vibration, and harshness (NVH) analysis of a transmission system, the elasticity of the gear mesh plays a crucial role in obtaining useful results. To help you create an accurate gear simulation, new features and functionality in the COMSOL Multiphysics® software enable you to evaluate gear mesh stiffness. Today, we’ll explain why it’s important to account for gear mesh elasticity as well as how to compute and include gear mesh stiffness in your multibody dynamics model.

### Analyze a Variety of Rotating Machines with the Rotordynamics Module

##### Caty Fairclough December 6, 2016

When modeling a rotating machine, it’s important to study the vibrations influencing its behavior in order to avoid machine failure. One way to accomplish this is with the new Rotordynamics Module, an expansion to the add-on Structural Mechanics Module for the COMSOL Multiphysics® software. Today, we’ll introduce you to the Rotordynamics Module and walk you through its helpful features and functionality for improving your rotating machinery design process.

### Can a Stiffness Be Negative?

##### Henrik Sönnerlind December 5, 2016

In finite element modeling, you may encounter formulations where a force does not monotonically increase with displacement. You can see this property in many material models that include degradation of the material. Such behavior is represented by a negative stiffness. In this blog post, we discuss some examples of negative stiffness, including the physical backgrounds and numerical implications. These ideas are not confined to mechanical analysis, even though the term stiffness originates in that field.

### Why Is Ice Slippery Enough for Skiing and Skating?

##### Brianne Costa December 2, 2016

Finding a scientific explanation for why ice is slippery seems simple enough, but it has actually been a subject of debate and confusion for centuries. As part of the world begins to bundle up for a blustery winter, let’s explore the science behind how the slipperiness of ice enables us to ski, skate, and even fall down in the parking lot.

### Why Doesn’t the Ice Cream in a Baked Alaska Melt?

##### Magnus Ringh November 18, 2016

One dessert that is sure to amaze your dinner guests is the baked Alaska. This classic treat consists of ice cream placed on a bed of sponge cake and covered in meringue. Although the dessert goes into a hot oven to caramelize the meringue, the ice cream inside surprisingly remains frozen. In this blog post, we use the heat transfer simulation capabilities of the COMSOL Multiphysics® software to find out how the baked Alaska works.

### Identify a Cricket Bat’s Sweet Spots with Structural Mechanics Analysis

##### Caty Fairclough November 11, 2016

In the highly competitive world of professional cricket, every swing is important. To deliver powerful shots, a batsman needs a well-designed bat and knowledge of how to best use it. One way to improve a player’s batting skills, and perhaps design better bats, is to locate their so-called “sweet spots”. A research team from the University of the West Indies achieved this by performing a structural analysis with the COMSOL Multiphysics® software.

### How to Use Acoustic Topology Optimization in Your Simulation Studies

##### GuestRené Christensen November 3, 2016

Today, guest blogger René Christensen of GN ReSound discusses the importance of acoustic topology optimization and how to apply it in COMSOL Multiphysics. Topology optimization is a powerful tool that enables engineers to find optimal solutions to problems related to their applications. Here, we’ll take a closer look at topology optimization as it relates to acoustics and how we optimally distribute acoustic media to obtain a desired response. Several examples will further illustrate the potential of this optimization technique.

### Optimizing a Tunable Organ Pipe for Ocean Acoustic Tomography

##### Caty Fairclough November 1, 2016

Ocean acoustic tomography systems measure temperature using an acoustic signal that travels between two instruments. These systems often need to cover a broad frequency band with low-frequency signals and require a high-power sound source. One option to achieve these goals is a tunable organ pipe, which balances efficiency and functionality. A researcher at the Advanced Technology Group, Teledyne Marine Systems used simulation to improve his tunable organ pipe design and compared the results to experimental tests.

### Modeling Fatigue Failure in Elastoplastic Materials

##### Mateusz Stec October 28, 2016

Imagine bending a metallic paper clip back and forth until, after a few repetitions, it breaks entirely. This is one example of fatigue failure, the most common type of structural collapse. In more severe cases, such failure can lead to collapse or malfunction in structures like car exhaust pipes and aircraft jet engines. To better understand and predict fatigue failure in elastoplastic materials, we can use the COMSOL Multiphysics® software to accurately model both the materials and the fatigue process.

### Analyze a Vacuum Dryer’s Speed with Multiphysics Modeling

##### Caty Fairclough October 19, 2016

In certain food and pharmaceutical industries, different types of dryers are used to dry heat-sensitive products. Vacuum dryers offer one solution for removing water and organic solvents from these sensitive substances. For optimal vacuum dryer design performance, engineers need to balance the dual needs of a rapid drying time and high-quality end products. To achieve this, you can study the vacuum drying process with the COMSOL Multiphysics® software.

### Understanding the Different Elements of Gear Modeling

##### Pawan Soami October 18, 2016

To accurately simulate a gear and obtain useful results, it is important to consider a number of elements behind the device’s design and how they are modeled. New features and functionality in the COMSOL Multiphysics® software provide you with the tools to address such properties and thus advance the reliability of your simulation studies. Today, we’ll review the various elements of gear modeling and explain how to account for them in our modeling processes.