Material Models Blog Posts
Modeling the Hydrostatic Pressure of a Fluid in a Deformable Container
Picture a water balloon being compressed at the center. As you squeeze the balloon, the locations of the highest point and depth of fluid change, altering the hydrostatic pressure distribution.
Computing and Controlling the Volume of a Cavity
See a method for modeling enclosed volumes containing incompressible fluids (under the additional assumption that the momentum and energy transfer via the fluid is small) in COMSOL Multiphysics®.
Submodeling: How to Analyze Local Effects in Large Models
Modeling a particularly large structure with a lot of boundary conditions? Learn how to use submodeling, a technique for analyzing local effects in large models in COMSOL Multiphysics®.
Why All These Stresses and Strains?
In structural mechanics you will come across a plethora of stress and strain definitions. It may be a Second Piola-Kirchhoff Stress or a Logarithmic Strain. In this blog post we will investigate these quantities, discuss why there is a need for so many variations of stresses and strains, and illuminate the consequences for you as a finite element analyst. The defining tensor expressions and transformations can be found in many textbooks, as well as through some web links at the […]
Fatigue Prediction Using Critical Plane Methods
Research on fatigue started in the 19th century, initiated following failing railroad axles that caused train accidents. In a rotating axle, stress varies from tension to compression and back to tension in one revolution. The load history is simple because it is uniaxial and proportional. Fatigue can then be evaluated with the S-N curve, also known as the Wöhler curve, which relates stress amplitude to a component’s life. In many applications we deal with multiaxiality and non-proportional loading. In this […]
Fatigue — When Cyclic Stress Produces Fractures
Many of the products that engineers design experience cyclic stresses during use that are below the material’s yield stress; unfortunately, these stresses can still be the primary reason for failure. Thus, engineers and designers must find ways of including the effects of cyclic stresses when designing products for long-term use.