## Modeling a Sphere Falling on a Water Surface

##### Chandan Kumar January 4, 2018

A sphere slightly lighter than water is dropped into a small liquid-filled beaker. How do you model the resulting shape of the water surface and the motion of the sphere as it floats on the surface? In this blog post, we demonstrate how to model this system in the COMSOL Multiphysics® software. Although we are considering the case of a small sphere, the technique discussed here can be applied to other larger shapes as well.

Ler Mais##### Chandan Kumar October 8, 2015

MEMS resonators are microelectromechanical systems primarily used as sensor elements, filters, and frequency elements. Two common actuation methods for MEMS resonators are piezoelectric actuation and electrostatic actuation. In this blog post, we will discuss the modeling of electrostatically actuated MEMS resonators. When modeling such resonators, you will often come across terms such as equilibrium point, pull-in, pull-in voltage, and time harmonic response of a biased resonator. We will explain these phenomena using a simple representation of an actuator.

Ler Mais##### Chandan Kumar June 24, 2015

Previously on the blog, we have discussed the need for appropriate measured data to fit the material parameters that correspond to a material model. We have also looked at typical experimental tests, considerations for operating conditions when choosing a material model, and an example of how to use your measured data directly in a nonlinear elastic model. Our focus today will be on how to fit your experimental data to different hyperelastic material models.

Ler Mais##### Chandan Kumar January 28, 2014

Here is an interesting question: How can we easily probe the solution at a point that is moving in time, but associated with a stationary geometry? One option is to use the General Extrusion coupling operator. In this blog post, we will take a look at how to use the General Extrusion coupling operator to probe a solution at a point in your geometry, and illustrate how to implement a dynamic probe using an example model.

Ler Mais##### Chandan Kumar April 3, 2013

Some structural applications involve thin or high aspect ratio structures sandwiched between other relatively low aspect ratio structures. For example, if a piezoelectric transducer is glued on the surface of a mechanical system, the thickness of the adhesive layer is very small in comparison to the two structures it glues together. Numerical modeling of such a thin layer in two or three dimensions requires resolving it with an appropriate finite element mesh. This can result in a large concentration of […]

Ler Mais