## What Is Geometric Nonlinearity?

##### Henrik SÃ¶nnerlind 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.

### Modeling a Stacked Piezoelectric Actuator in a Valve

##### Brianne Costa May 13, 2015

Piezoelectric valves are opened and closed by stacked piezoelectric actuators that are positioned above a seal. By applying a voltage to the stacked piezoelectric actuator, it can be made to expand or contract and the resulting deformation is used to open and close the valve. In this blog post, we feature a tutorial model of a stacked piezoelectric actuator in a pneumatic valve, new with COMSOL Multiphysics version 5.1.

### Simulating the Insertion of a Snap Hook

##### Bridget Cunningham March 31, 2015

Commonly used in the automotive industry, snap hooks are a type of fastener that involve the insertion of a hook into a slot. When designing snap hooks, it is important to analyze the forces required for the insertion of the hook as well as its removal. We can address this through simulation.

### Introducing Nonlinear Elastic Materials

##### Ed Gonzalez January 9, 2015

Nonlinear elastic materials present nonlinear stress-strain relationships even at infinitesimal strains — as opposed to hyperelastic materials, where stress-strain curves become significantly nonlinear at moderate to large strains. Important materials of this class are Ramberg-Osgood for modeling metals and other ductile materials and nonlinear soils models, such as the Duncan-Chang model.

### New Piezoelectric Modeling Interface in COMSOL 5.0

##### Supratik Datta December 30, 2014

We have introduced a new interface for simulating piezoelectric devices in version 5.0 of the COMSOL Multiphysics simulation software. This interface aims to achieve several things. In this blog post, I will explain what these things are and how you can use them.

### Membrane Interface Improvements in Version 5.0

##### Ashish Kumar Singh December 11, 2014

The Membrane interface has undergone a number of changes with the release of COMSOL Multiphysics version 5.0. This includes a restructured menu, new feature nodes, improvements to the Linear Elastic Material model, and support for the Hyperelastic Material model. You might remember the Nonlinear Structural Materials model Inflation of a Spherical Rubber Balloon. We have now rebuilt it using the Membrane interface. I will discuss these changes and the new model in today’s blog post.

### How to Model Residual Stresses Using COMSOL Multiphysics

##### Fabio Bocchi June 5, 2014

Today, we will introduce the concept of residual stresses in structural mechanics and find out how to compute them by taking the example of a deep metal drawing process. First, we will explain how they can be computed and interpreted in a bending beam example with or without work hardening. Then, we will introduce a sheet metal forming model.