## Simulating Powder Compaction with Porous Plasticity Models

##### Bridget Cunningham June 12, 2017

In the last seven years, the output of the manufacturing industry has increased by a total of around 10–20%. This growth is partly thanks to technologies and processes that save on time and costs, such as 3D printing and, as is described here, powder compaction. To model this process, we can use the new porous plasticity models in the latest version of the COMSOL Multiphysics® software.

### How to Model Heat and Moisture Transport in Air with COMSOL®

##### Claire Bost June 9, 2017

Whenever ambient air is considered in an engineering context, temperature and moisture are intrinsically related. Vapor reaches a saturation point depending on the temperature and pressure conditions, while the action of latent heat modifies temperature distribution. These phenomena must be considered to optimize processes affected by phase changes, particularly when trying to prevent condensation occurring in devices. Let’s see how to model heat and moisture transport in air with the COMSOL Multiphysics® software.

### Optimizing Microwave Furnaces for Solar-Grade Silicon Production

##### Bridget Paulus June 8, 2017

Solar-grade silicon is becoming more popular for applications such as communications and photovoltaics. While it’s important to keep up with this growing demand, the current method of producing solar-grade silicon is energy intensive and expensive. To find a more efficient process, researchers at JPM Silicon GmbH explored a novel method using a microwave furnace. By simulating the internal processes, they aim to optimize their microwave furnace design to produce low-cost solar-grade silicon.

### How to Calculate a Capacitance Matrix in COMSOL Multiphysics®

##### Sven Friedel June 7, 2017

Capacitance calculations in the COMSOL Multiphysics® software seem easy. If you only have two conductors, the recipe is simple: Take one conductor and set it to grounded, set the other as a terminal, and compute the solution. Then, a built-in variable delivers the capacitance. But what if you have more than two conductors, like in touchscreens, transmission lines, and capacitive sensors? If standard textbook terminology has you lost, follow along with this working example of calculating a capacitance matrix.

### How to Model the Optical Properties of Rough Surfaces

##### Walter Frei June 6, 2017

Whenever light is incident on a dielectric material, like glass, part of the light is transmitted while another part is reflected. Sometimes, we add a metal coating, such as gold, which alters the transmittance and reflectance as well as leads to some absorption of light. The dielectric surface and the metal coating also often have some random variations in height and thickness. In this blog post, we will introduce and develop a computational model for this situation.

### How to Create a Randomized Geometry Using Model Methods

##### Walter Frei June 5, 2017

Have you ever wanted to include a randomly created geometry in your model? Perhaps you want to simulate a natural material or an arrangement of parts that has some known statistical distribution of dimensional variations. In such cases, we may want to create a random geometry in the COMSOL Multiphysics® software. With the release of version 5.3, we can now create random geometries using a model method. Let’s take a look at how to do so with a tasty example.

### How to Generate Random Surfaces in COMSOL Multiphysics®

##### Bjorn Sjodin June 2, 2017

To easily generate random-looking geometric surfaces, the COMSOL Multiphysics® software provides a powerful set of built-in functions and operators, such as functions for uniform and Gaussian random distributions and a very useful sum operator. In this blog post, we show you how to generate a randomized surface with what amounts to a “one liner” expression with detailed control of the constituent spatial frequency components that determine the nature of the surface’s roughness.

### Computing the Band Gap in Superlattices with the Schrödinger Equation

##### Chien Liu May 31, 2017

You can use the new Schrödinger Equation interface for modeling with the Semiconductor Module in the latest release of the COMSOL® software. Let’s look at a simple example app that uses this interface to estimate the electron and hole ground state energy levels for a superlattice structure. By building apps like this one, device engineers are able to calculate the band gap for a given periodic structure and adjust the design parameters until a desired band gap value is achieved.

### Studying Stress in Threaded Pipe Fitting Designs from CAD Assemblies

##### Bridget Cunningham May 30, 2017

Every year, over 40 million fire sprinkler systems are fitted worldwide. These systems are effective due to their piping designs, which are resistant to high heat and mechanical damage. A popular choice for such designs is threaded steel pipe. But analyzing a complex pipe design is challenging because of the detailed geometry. What approach can we take to efficiently combine accurate geometrical designs with reliable stress analyses? Version 5.3 of the COMSOL® software offers functionality for this purpose.

### Efficiently Optimizing Solar Dish Receiver Designs

##### Caty Fairclough May 29, 2017

When designing a solar dish receiver, you may need to rerun your simulation multiple times to find an optimized design iteration. To save time, you can build an app that enables you to rapidly test different geometries and more easily create improved designs. Let’s explore a new simulation app in COMSOL Multiphysics® version 5.3, the Solar Dish Receiver Designer, which you can use as inspiration for building apps of your own.

### Analyzing Critical Speeds with the Rotor Bearing System Simulator

##### Prashant Srivastava May 25, 2017

Rotating components are important elements in machines such as gas turbines, turbochargers, pumps, compressors, electric generators, and motors. Designing such a component requires studying its critical speed, which is the speed at which the amplitude of the vibration in the system becomes large — often leading to failure. Let’s explore how to find the critical speeds for a wide range of rotors via the Rotor Bearing System Simulator, created using the COMSOL Multiphysics® software.