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General Blog Posts

How to Model Large-Strain Viscoelasticity in COMSOL Multiphysics®

October 11, 2016

Many polymers and biological tissues exhibit viscoelastic deformation, which has a time-dependent response even if the loading is constant in time. Linear viscoelasticity, where the stress depends linearly on the strain and strain rate, is a common approximation. We usually assume that the viscous part of the deformation is incompressible, so the volumetric deformation is purely elastic. As of COMSOL Multiphysics® 5.2a, you can model large-strain viscoelasticity besides linear viscoelasticity. See how to use this material model in a biomedical […]

Understand the Dynamics of the FitzHugh-Nagumo Model with an App

October 7, 2016

In 1961, R. Fitzhugh (Ref. 1) and J. Nagumo proposed a model for emulating the current signal observed in a living organism’s excitable cells. This became known as the FitzHugh-Nagumo (FN) model of mathematical neuroscience and is a simpler version of the Hodgkin-Huxley (HH) model (Ref. 2), which demonstrates the spiking currents in neurons. In today’s blog post, we’ll examine the dynamics of the FN model by building an interactive app in the COMSOL Multiphysics® software.

Integrals with Moving Limits and Solving Integro-Differential Equations

October 6, 2016

In a previous blog post, we discussed integration methods in time and space, touching on how to compute antiderivatives using integration coupling operators. Today, we’ll expand on that idea and show you how to analyze spatial integrals over variable limits, whether they are prescribed explicitly or defined implicitly. The technique that we will describe can be helpful for analyzing results as well as for solving integral and integro-differential equations in the COMSOL Multiphysics® software.

Guidelines for Equation-Based Modeling in Axisymmetric Components

October 5, 2016

Cylindrical coordinates are useful for efficiently solving and postprocessing rotationally symmetric problems. The COMSOL Multiphysics® software has built-in support for cylindrical coordinates in the axisymmetry physics interfaces. When defining custom partial differential equations (PDEs) using the mathematical interfaces, paying close attention to their meaning is important. The PDE interfaces assume partial differentiation in a Cartesian system, requiring manual coordinate transformations to change to a cylindrical system. See how to account for such coordinate transformations when using your own PDEs.

Improved Capabilities for Meshing with Tetrahedral Elements

September 27, 2016

To help optimize your modeling processes, we are continuously striving to enhance the quality of our meshing capabilities. The recent improvements to the algorithm for generating tetrahedral meshes in the COMSOL Multiphysics® software are one such example. Follow along as we guide you through the process of generating a tetrahedral mesh to highlight this improved functionality and its correlating features, while discussing its role in helping you obtain better simulation results.

Efficiently Assign Materials in Your COMSOL Multiphysics® Model

September 20, 2016

To optimize your modeling processes, there are a number of built-in materials available for you to use in the COMSOL Multiphysics® software. Along with these materials are features and functionality that allow you to efficiently assign materials to geometric entities in your model. These tools help expedite the process of assigning materials, specifying material properties, and even comparing the impact of different materials on your simulation results. Here, we’ll highlight three tutorial videos that showcase how to use such tools.

Improved Functionality and Tips for Importing STL and NASTRAN® Files

September 14, 2016

STL files originating from 3D scan sources and meshes in the NASTRAN® file format are often used as bases for geometries. However, performing simulations on these realistic objects can be challenging, particularly when preparing the geometry. The COMSOL Multiphysics® software contains features for dealing with these files. Learn how to utilize this functionality as well as how to achieve good results when importing STL and NASTRAN® files.

Study the Design of a Polarizing Beam Splitter with an App

September 12, 2016

Polarizing beam splitters are optical devices used to split a single light beam into two beams of varying linear polarizations. These devices are useful for splitting high-intensity light beams like lasers as, unlike absorptive polarizers, they do not absorb or dissipate the energy of the rejected polarization state. See why creating a numerical modeling app offers a more efficient approach to analyzing and optimizing the design of these devices.