# Blog

## 21 Sep 2021Stress Concentration Factor

Besides the surface factor (https://www.fea-solutions.co.uk/surface-factor/), the stress concentration factor or notch sensitivity is another key modification that could reduce the endurance limit. The stress concentration factor is used to account for the effect of irregularities or discontinuities such as holes, grooves or notches that are not...

## 14 Sep 2021Surface Factor

The endurance limit (https://www.fea-solutions.co.uk/s-n-curves/) of a material is either obtained from a fatigue test (https://www.fea-solutions.co.uk/static-test-vs-fatigue-test/) or estimated using the ultimate tensile strength of the material if the test data is not available. Such an endurance limit does however not take into account the effects of...

## 07 Sep 2021E-N Curves

When conducting a strain based fatigue analysis (https://www.fea-solutions.co.uk/strain-based-fatigue-analysis/), the E-N curves of the materials used are required, where E stands for ε (epsilon), the symbol for strain, and N for the number of loading cycles with the graph showing the mean stress over the number...

## 31 Aug 2021S-N Curves

When conducting a stress based fatigue analysis (https://www.fea-solutions.co.uk/stress-based-fatigue-analysis/), the S-N curves of the materials used are required, where S stands for σ (sigma), the symbol for stress, and N for the number of loading cycles with the graph showing the mean stress over the number...

## 24 Aug 2021Static Test vs Fatigue Test

Static Test vs Fatigue Test To obtain mechanical properties for a material, physical specimen tests are performed depending on the types of material properties that are desired. Two examples of these tests are: - Static specimen test - Fatigue specimen test. Static tests are used to obtain the mechanical...

## 17 Aug 2021Fatigue Analysis

A fatigue analysis is performed to calculate whether a structure will fail after a certain number of repeated loading and unloading, so-called load cycles, rather than after one load cycle as simulated in a static analysis. The fatigue failure is due to initiation and propagation...

## 10 Aug 2021Fatigue

Since the beginning of mechanical engineering, static (https://www.fea-solutions.co.uk/static-vs-dynamic-analysis/) tests have been used to determine the strength of designs. This was suitable for structures such as houses, towers and bridges, subjected to static loads due to self weight (https://www.fea-solutions.co.uk/mass-and-weight/). With the Industrial Revolution, machines were introduced...

## 03 Aug 2021Neuber’s Rule

When performing a FEA stress analysis, a linear-elastic (https://www.fea-solutions.co.uk/elasticity-and-plasticity/) material model is usually selected. In case the resulting peak stresses are found to be above the yield strength of the material, the underlying assumption that the material would behave in a linear-elastic manner has been...

## 27 Jul 2021Weld Representation in FEA

When a welded component is simulated in FEA, there are two ways to represent the welds: - Treating the welded components as a single part. - Modelling the weld seam in detail. As in most cases the weld geometry is small compared to the overall size of the...

## 20 Jul 2021Hyperelastic Material

The most common construction materials in mechanical engineering are metals and plastics. In the normal range of use, their mechanical behaviour can be mathematically described as linear-elastic https://www.fea-solutions.co.uk/elasticity-and-plasticity/. Soft rubbers and foams are elastic as well, but their stress-strain curves (https://www.fea-solutions.co.uk/stress-strain-curves/) are highly non-linear. This is...