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. In COMSOL Multiphysics® 5.2a, you can model large-strain viscoelasticity besides linear viscoelasticity. See how to use this material model in a biomedical application.

Pressure vessels are designed to confine liquids or gases. These containers are used in nuclear plants, throughout the chemical and petroleum industries, and even as water heaters in homes. In principle, the vessels’ internal pressure is much higher (or sometimes lower) than the ambient pressure, so the vessels must be carefully designed, as failure can result in severe damage. Today, we’ll show you how to use the Application Builder in COMSOL Multiphysics to create an efficient and accurate design workflow.

When performing structural mechanics analyses, you will inevitably encounter the concept of geometric nonlinearity. In this blog post, we discuss what is meant by geometric nonlinearity and when you should take this effect into consideration.

When an earthquake strikes, the force from its seismic waves can weaken the stability of buildings. By implementing seismic control measures, designers can enhance the flexibility of such structures as well as strengthen their safety levels. See how one research team used COMSOL Multiphysics to study the impact of base isolation systems and explore approaches to optimizing their performance.

Nonlinear elastic materials present nonlinear stress-strain relationships even at infinitesimal strains — as opposed to hyperelastic materials, where stress-strain curves become significantly nonlinear at moderate to large strains. Important materials of this class are Ramberg-Osgood for modeling metals and other ductile materials and nonlinear soils models, such as the Duncan-Chang model.

For gas pipeline maintenance standards, the adage “rules are meant to be broken” may not apply, but “rules are meant to be updated” certainly does. Specifically, the generous distance requirements between pipeline squeeze-off locations and pipe fittings cause potentially unnecessary digging. This prompted Operations Technology Development (OTD), a partnership of natural gas distribution companies, to initiate a project with Gas Technology Institute (GTI), where researchers used simulation to investigate the standard distance requirements for streamlined and safe pipeline maintenance.

Arteries are designed to carry blood containing oxygen and nutrients from the heart to other areas of the body. Studying this biological soft tissue from a mechanical standpoint requires a reliable model that can fully describe the arteries’ anisotropic nonlinear response. Our tutorial of arterial wall mechanics illustrates such a design.

Piezoelectric valves are opened and closed by stacked piezoelectric actuators that are positioned above a seal. By applying a voltage to the stacked piezoelectric actuator, it can be made to expand or contract and the resulting deformation is used to open and close the valve. In this blog post, we feature a tutorial model of a stacked piezoelectric actuator in a pneumatic valve, new with COMSOL Multiphysics version 5.1.

Commonly used in the automotive industry, snap hooks are a type of fastener that involve the insertion of a hook into a slot. When designing snap hooks, it is important to analyze the forces required for the insertion of the hook as well as its removal. We can address this through simulation.

We have introduced a new interface for simulating piezoelectric devices in version 5.0 of the COMSOL Multiphysics simulation software. This interface aims to achieve several things. In this blog post, I will explain what these things are and how you can use them.