General Blog Posts
Nonlinearity Ramping for Improving Convergence of Nonlinear Problems
As we saw in “Load Ramping of Nonlinear Problems“, we can use the continuation method to ramp the loads on a problem up from an unloaded case where we know the solution. This algorithm was also useful for understanding what happens near a failure load. However, load ramping will not work in all cases, or may be inefficient. In this posting, we introduce the idea of ramping the nonlinearities in the problem to improve convergence.
Dedicated Multiphysics Node Introduced in COMSOL 4.4
To make it easier and more transparent to define models involving multiple physics phenomena in COMSOL, a separate Multiphysics node has been added as a new feature in COMSOL version 4.4. The Multiphysics node gives you control over the couplings for thermal stress and electromagnetic thermal effects involved in your models. Future versions will include further multiphysics couplings through the Multiphysics node in addition to the multiphysics couplings methods already available since previous versions.
Video Tutorial: Introducing the New User Interface in COMSOL 4.4
Each COMSOL release aims to create a better modeling experience for our users, usually in the form of new add-on modules and new functionality in existing products. COMSOL 4.4 brings you all that, but it also includes another significant change: a brand new user interface (UI). The new UI contains a ribbon at the top of the interface (for our Windows® users) to make your modeling easier and faster. The ribbon gives you direct access to the functions you would […]
Load Ramping of Nonlinear Problems
As we saw previously in the blog entry on Solving Nonlinear Static Finite Element Problems, not all nonlinear problems will be solvable via the damped Newton-Raphson method. In particular, choosing an improper initial condition or setting up a problem without a solution will simply cause the nonlinear solver to continue iterating without converging. Here we introduce a more robust approach to solving nonlinear problems.
Solving Nonlinear Static Finite Element Problems
Here, we begin an overview of the algorithms used for solving nonlinear static finite element problems. This information is presented in the context of a very simple 1D finite element problem, and builds upon our previous entry on Solving Linear Static Finite Element Models.
Solutions to Linear Systems of Equations: Direct and Iterative Solvers
In this blog post we introduce the two classes of algorithms that are used in COMSOL to solve systems of linear equations that arise when solving any finite element problem. This information is relevant both for understanding the inner workings of the solver and for understanding how memory requirements grow with problem size.
Meshing Your Geometry: When to Use the Various Element Types
In a previous blog entry, we introduced meshing considerations for linear static problems. One of the key concepts there was the idea of mesh convergence — as you refine the mesh, the solution will become more accurate. In this post, we will delve deeper into how to choose an appropriate mesh to start your mesh convergence studies for linear static finite element problems.
Philosophy of the Ribbon
Over the past few years, Microsoft® has introduced updates to the user interface (UI) for its Office programs. Microsoft® Office 2013 is all about being touch-screen friendly, and Microsoft® Office 2007 brought the Ribbon interface. The Microsoft® Ribbon was designed to be easier to use than the nested drop-down menus of yore. These days, it’s what we’re used to seeing when working with their tools — and we’ve come to appreciate the ease-of-use, guidance, and clear workflow overview it provides. […]