# Blog

## 19 JulLarge Deformation

Large deformation, or geometric non-linearity, is one of the three non-linear behaviours in structural analysis, see: (https://fea-solutions.co.uk/non-linear-behaviour/) In linear analysis, the equilibrium of forces (and moments) is established on the undeformed structure. That means, although one of the results of the FEA are deformations, the calculation...

## 10 JulNon-Linear Material

Non-linear material behaviour is one of the three non-linear behaviours in structural analysis, see: (https://fea-solutions.co.uk/non-linear-behaviour/) When talking about non-linear materials, most people think about plastic behaviour. This is however just one of several non-linear materials. They are: Plasticity This describes the non-reversible deformation of a solid part, see:...

## 05 JulNon-Linear Behaviour

Numerical simulation, including FEA, is well suited to realistically predict non-linear behaviour of physical phenomena. Looking just at structural analysis, there are three different types of non-linear behaviour. They are: Non-Linear Material This has to be considered if the material doesn't behave linear-elastically. Read more about these...

## 27 JunFactor of Safety

To assess if a structure is suitable for the intended purpose, the results of a FE analysis have to be compared to acceptance criteria, also called allowables. For a stress analysis, allowables could be e.g. equivalent stresses (see https://fea-solutions.co.uk/equivalent-stress/) or deflections. The Factor of Safety (FoS) is...

## 21 JunEquivalent Stress

The stress results of a FE analysis are three-dimensional tensors, see: (https://fea-solutions.co.uk/stress-tensor/) Material properties including Yield Strength and Ultimate Strength are however usually derived from uniaxial tests, e.g. tensile tests, see: (https://fea-solutions.co.uk/tensile-tests/) Depending on the material used and its failure mode, there are different conversions done: For...

## 14 JunStress Tensor

For anybody who wants to assess FEA results, it is important to understand the concept of the Stress Tensor. A tensor is a mathematical entity. Other, more commonly known mathematical entities are scalars and vectors (although these two are actually just special forms of tensors). Simply speaking,...

## 07 JunEngineering Stress vs True Stress

The data obtained from a Tensile Test (https://fea-solutions.co.uk/tensile-tests/) are forces and displacements. In order for this to be useful to an engineer, the applied force has to be converted into a stress. (https://fea-solutions.co.uk/stress-strain-curves/) There are two types of stress which can be calculated, Engineering Stress and True...

## 31 MayElastic Modulus

In Hooke's Law (https://fea-solutions.co.uk/law-of-elasticity/), the Spring Constant k describes the relation between an applied load and the resulting deformation of a body. It depends on both the shape (geometry) of the part as well as its material. To have a constant that is just depending on the...

## 24 MayLaw of Elasticity

The Law of Elasticity, or Hooke's Law, is a brilliantly simple form to express the elastic deformation of a body. In our times, this Law of Physics is practically known by most people, but it was revolutionary when first stated in 1660 by the British...

## 17 MayDeformation Behaviour

The shape of a Stress-Strain Curve allows a handy overview on the deformation behaviour of a material. Please read (https://fea-solutions.co.uk/stress-strain-curves/) for information on how Stress-Strain Curves are generated. For many materials, the Stress-Strain Curve is a straight line up to the Yield point. Such a behaviour is...