## Applying and Interpreting Saint-Venant’s Principle

##### Henrik Sönnerlind January 22, 2018

All structural engineers use Saint-Venant’s principle, whether actively or subconsciously. You can find various formulations of this principle in most structural mechanics textbooks, but its exact meaning is not obvious. Saint-Venant’s principle tells us that the exact distribution of a load is not important far away from the loaded region, as long as the resultants of the load are correct. In this blog post, we will explore Saint-Venant’s principle, particularly in the context of finite element (FE) analysis.

### Analyzing a MEMS-Based Strain Gauge Design with Simulation

##### Bridget Paulus January 19, 2018

In civil engineering and the biomedical field, strain gauges are used to measure deformation sustained by various objects. Typically, foil gauges are used, but they have low sensitivity. MEMS-based gauges, like the double-ended tuning fork (DETF) strain gauge, offer better performance. To optimize the design of a new DETF strain gauge, researchers used the COMSOL Multiphysics® software and compared the results to an analytical model.

### Predicting Solute Transport in Groundwater Using Simulation

##### Caty Fairclough January 18, 2018

While our daily lives are clearly affected by the “flashier” parts of the water cycle (rain, snow, etc.), other parts of the cycle — such as the groundwater moving beneath our feet — are just as important. We use groundwater for irrigation and drinking water, and it affects natural processes and habitats. When studying groundwater, it’s often important to understand the movement of various solutes through the water. To predict solute transport, scientists can use multiphysics simulation.

### Model Deforming Objects with the Arbitrary Lagrangian-Eulerian Method

##### Edmund Dickinson January 17, 2018

As two of the greatest mathematicians to have ever lived, Leonhard Euler and Joseph-Louis Lagrange made numerous contributions to continuum mechanics. Combining their individual descriptions of the subject inspired the arbitrary Lagrangian-Eulerian (ALE) method, a technique that can be used for a multitude of simulation applications. Find out how the work of Euler and Lagrange helped create the ALE method and how it aids your simulations in the COMSOL Multiphysics® software.

### Studying the Safety of Tattoos with Mass Spectrometry and X-Rays

##### Brianne Costa January 12, 2018

“Where?” “Of what?” “Why?” These are questions often asked of someone who is planning on getting a tattoo. Another common question: “Is it safe?” You can vet the cleanliness of a tattoo parlor and the artist’s qualifications, but there hasn’t been much research into what happens to ink once it enters the body. A research group recently investigated if tattoo pigment can harm skin and the lymphatic system using techniques such as mass spectrometry and X-ray fluorescence.

### Analyzing the Mechanical Behavior of Cells for Biological Applications

##### GuestBjörn Fallqvist January 11, 2018

Today, guest blogger Björn Fallqvist of Lightness by Design, a COMSOL Certified Consultant, discusses using simulation to provide insight into the mechanical behavior of cells. Biological cells are essential for life as we know it. They not only store and replicate hereditary information in the form of DNA but also are instrumental in biological processes. In most, if not all, of these processes, the mechanical behavior of cells is a main factor in ensuring normal physiological functions.

### Analyzing White Pupil Échelle Spectrographs via Ray Tracing Simulation

##### Caty Fairclough January 10, 2018

11 light-years away from our solar system, an exoplanet called Ross 128 b orbits a red dwarf star. This planet has the potential to support life and is the second-closest temperate planet discovered, with a surface temperature that might be similar to Earth’s. Astronomers detected Ross 128 b by using data from an échelle spectrograph called HARPS. To further advance the search for Earth-mass exoplanets, we can improve the sensitivity of échelle spectrographs using the COMSOL Multiphysics® software.

### How to Use the Beam Envelopes Method for Wave Optics Simulations

##### Yosuke Mizuyama January 8, 2018

In the wave optics field, it is difficult to simulate large optical systems in a way that rigorously solves Maxwell’s equation. This is because the waves that appear in the system need to be resolved by a sufficiently fine mesh. The beam envelopes method in the COMSOL Multiphysics® software is one option for this purpose. In this blog post, we discuss how to use the Electromagnetic Waves, Beam Envelopes interface and handle its restrictions.

### Evaluating the Performance of a Steam Reformer with COMSOL®

##### Caty Fairclough January 5, 2018

Steam reformers are commonly used for power and energy generation processes. To accurately analyze the performance of a steam reformer design, you need to be able to couple mass, energy, and flow equations. Using the COMSOL Multiphysics® software, you can set up a model of a steam reformer that represents its real-world behavior and operating conditions.

### 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.

### Modeling Cables in COMSOL Multiphysics®: 6-Part Tutorial Series

##### Brianne Costa December 29, 2017

Want a roadmap to modeling cables? We have a six-part tutorial series for you. The Cable Tutorial Series shows how to model an industrial-scale cable in the COMSOL Multiphysics® software and add-on AC/DC Module, and also serves as an introduction to modeling electromagnetic phenomena in general. The numerical model is based on standard cable designs and validated by reported figures. Keep reading for a sneak peek of what you’ll learn when you roll up your sleeves and start the series.