Author: fea_user

25 Jul 2019Non-Linear Contact

Non-linear contact is one of the three non-linear behaviours in structural analysis, see: https://www.fea-solutions.co.uk/non-linear-behaviour/ Non-linear contact is required where the load path between parts of an assembly is affected by the load direction. A typical example where non-linear contact has to be taken into account is a bolted...

19 Jul 2019Large Deformation

Large deformation, or geometric non-linearity, is one of the three non-linear behaviours in structural analysis, see: https://www.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 has...

10 Jul 2019Non-Linear Material

Non-linear material behaviour is one of the three non-linear behaviours in structural analysis, see: https://www.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: https://www.fea-solutions.co.uk/elasticity-and-plasticity/ Viscoelasticity This is...

05 Jul 2019Non-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 Jun 2019Factor 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://www.fea-solutions.co.uk/equivalent-stress/) or deflections. The Factor of Safety (FoS) is...

21 Jun 2019Equivalent Stress

The stress results of a FE analysis are three-dimensional tensors, see: https://www.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://www.fea-solutions.co.uk/tensile-tests/ Depending on the material used and its failure mode, there are different conversions done: For ductile materials...

14 Jun 2019Stress 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 Jun 2019Engineering Stress vs True Stress

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

31 May 2019Elastic Modulus

In Hooke's Law, the Spring Constant k describes the relation between an applied load and the resulting deformation of a body. https://www.fea-solutions.co.uk/law-of-elasticity/ 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 material...

24 May 2019Law 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...