## Introduction to Numerical Integration and Gauss Points

##### Henrik Sönnerlind May 1, 2019

In this comprehensive blog post, we go over the theory behind numerical integration, Gaussian quadrature, Gauss points, weak contributions, and much more.

### How to Model Different Types of Damping in COMSOL Multiphysics®

##### Henrik Sönnerlind March 15, 2019

Structural dynamics analyses can be difficult if you have to account for damping. Get a demonstration of how to use the different numerical models for damping in COMSOL Multiphysics. Part 2 of 2.

### Damping in Structural Dynamics: Theory and Sources

##### Henrik Sönnerlind March 14, 2019

Here’s your introduction to the theory behind damping in vibrating structures, as well as its sources, including internal losses, friction, sound emission, and more. Part 1 of 2.

### How to Perform Structural Analyses Using Shock Response Spectra

##### Henrik Sönnerlind January 30, 2019

Mechanical engineers: Learn how to find shock response spectra, use combination methods for eigenmodes, perform missing mass correction, and display your results with the COMSOL® software.

### Finding Answers to the Tuning Fork Mystery with Simulation

##### Henrik Sönnerlind April 13, 2018

If you strike a tuning fork and hold it against a tabletop, the peak frequency of the emitted sound doubles. Is there a physical explanation for this “tuning fork mystery”?

### Applying and Interpreting Saint-Venant’s Principle

##### Henrik Sönnerlind 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

##### Henrik Sönnerlind 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®

##### Henrik Sönnerlind 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?

##### 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.

### How to Model Adhesion and Decohesion in COMSOL Multiphysics

##### Henrik Sönnerlind 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

##### Henrik Sönnerlind 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.