# COMSOL Blog

## Modeling Bone Strength Using Isotropic and Anisotropic Materials

##### Laura Bowen | December 20, 2013

The question of exactly how strong living bones are poses many important considerations for the medical industry. There is not currently a single-purpose device in the field to test bone strength. However, it is possible for researchers to get measurements of bone strength by modeling the entire makeup of the bone and using multiphysics simulation to perform stress and strain analyses. Simulating bone strength starts with a simple map of the external topology of the bone and then delves into […]

### Why All These Stresses and Strains?

##### Henrik Sönnerlind | November 21, 2013

In structural mechanics you will come across a plethora of stress and strain definitions. It may be a Second Piola-Kirchhoff Stress or a Logarithmic Strain. In this blog post we will investigate these quantities, discuss why there is a need for so many variations of stresses and strains, and illuminate the consequences for you as a finite element analyst. The defining tensor expressions and transformations can be found in many textbooks, as well as through some web links at the […]

### Simulating Tensile Stress in a Tube Connection with Prestressed Bolts

##### Alexandra Foley | September 26, 2013

When analyzing a bolted joint, one thing to consider for an accurate analysis is the bolt pretension. With COMSOL Multiphysics, the effects of prestressing a bolt can be easily computed using the Bolt Pre-tension feature available in the Structural Mechanics Module. After modeling prestressed bolts, a further analysis can then be conducted on an external load applied to the structure. Here, we will explore how to include prestressed bolts in a tube connection model, and then carry out a stress […]

### Simulating Thermal Stress in a Turbine Stator Blade

##### Nicolas Huc | September 18, 2013

We can leverage simulation software to understand and optimize component design. Every simulation relies on a model that is a representation of the reality that the application finds itself in. Modeling enables us to represent this reality with enough detail to receive relevant information about the particular application or component. Let’s have a look at a thermal stress analysis of the turbine stator blade model from our Model Gallery and investigate the effects of heat transfer and thermal stress that […]

### Starting Small with Sonar Dome Design

##### Andrew Griesmer | September 13, 2013

Starting the design process by testing on a small scale is often the best way to tackle issues affecting large objects, like a ship. Detailed in COMSOL News 2013, researchers at INSEAN, The Italian Ship Model Basin, used small-scale testing and then simulation to analyze the effect of placing a sonar system within the bulbous bow at the hull of a ship. Using a small-scale model of a bulbous bow, the researchers at INSEAN performed fluid-structure interaction experiments, and subsequently […]

### Modeling Magnetostriction Using COMSOL

##### Supratik Datta | August 26, 2013

If you have ever stood next to a transformer, you have probably heard a humming sound coming from it and wondered if there were bees close by. When you hear that sound the next time, you can rest assured that it’s not bees but the magnetostriction of the transformer core that is making that humming sound.

### Fatigue Prediction Using Critical Plane Methods

##### Mateusz Stec | July 22, 2013

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 […]

### Simulating an Engine Governor, the Spring Loaded Centrifugal Governor

##### Alexandra Foley | July 5, 2013

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 […]

### Aircraft Landing Gear Mechanism Analysis

##### Fanny Littmarck | July 3, 2013

Aircraft rely on landing gear in order to taxi, take off, and land. The landing gear of your average commercial airplane consists of a shock-absorber cylinder and piston, and a pair of tires. Intuitively, the shock-absorber experiences stresses as the landing gear touches the ground — but how much? In order to design a landing gear mechanism that can withstand many landings, and to determine when it’s time to swap out an old one, we can perform a multibody dynamics […]

### Structural Mechanics Tutorials: Rigid Connector and Linear Buckling

##### Andrew Griesmer | June 6, 2013

Continuing our structural mechanics tutorial blog series, we have created two more videos of different functionality existing in COMSOL’s Structural Mechanics Module. The first post in the series introduced you to the Structural Mechanics Module via a linear elastic analysis of a bracket, and the following post included two supplemental videos for adding Initial Strain and Thermal Stress to the this model. Next up we have two more “mini-tutorials” — this time outlining the Rigid Connector feature and the Linear […]