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All posts by Henrik Sönnerlind

Applying and Interpreting Saint-Venant’s Principle

January 22, 2018

Saint-Venant’s principle is found in most structural engineering textbooks, but what is its exact meaning? We go over its history, definition, and relevance to mechanical analyses.

How to Analyze Eigenfrequencies That Change with Temperature

May 22, 2017

In certain scenarios, such as in the MEMS field, the eigenfrequencies of a device can change with temperature. Here’s a guide to studying temperature-dependent eigenfrequencies.

Introduction to Modeling Stress Linearization in COMSOL Multiphysics®

May 16, 2017

Your complete introduction to the theory and process for modeling stress linearization in COMSOL Multiphysics®, as well as an overview of common real-world uses for this phenomenon.

Can a Stiffness Be Negative?

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.

How to Model Adhesion and Decohesion in COMSOL Multiphysics

July 28, 2016

As of COMSOL Multiphysics® version 5.2a, we bring you features designed to enhance your structural mechanics contact modeling. You can, for instance, simulate objects that stick together once they come in contact (adhesion) as well as those that pull apart (decohesion), including full cohesive-zone modeling. Learn how to address each of these scenarios using the new functionality in COMSOL Multiphysics.

How to Make Boundary Conditions Conditional in Your Simulation

June 27, 2016

Say you are working on a modeling case where loads are moving in such a way that they cross over different mesh elements and boundaries during the simulation. In these cases, among other instances, you may want to apply a boundary condition to only part of the geometrical boundary or only under certain conditions. In this blog post, we’ll discuss how you can utilize the flexibility of COMSOL Multiphysics to handle such situations.

Modeling the Dynamics of a Gyroscope

December 22, 2015

After recently encountering the equations of motion for rotating bodies for the first time, one of my sons came home with a number of interesting questions. His questions brought about a flashback, as I remembered sharing this sense of confusion when studying mechanics many years ago. In today’s blog post, I will present two COMSOL Multiphysics models — one of a gyroscope and one of a spinning top — that illustrate the remarkable properties of rotating bodies.

What Is Geometric Nonlinearity?

September 14, 2015

When performing structural mechanics analyses, you will inevitably encounter the concept of geometric nonlinearity. In this blog post, we discuss what is meant by geometric nonlinearity and when you should take this effect into consideration.