In real world applications all materials and products are subjected to a wide variety of vibrating or oscillating forces. Fatigue testing involves alternating, or cyclic application of stress or strain on a material or component. This loadings can cause damage or crack growth at stresses that are well below the yield strength of the material or component. Damage also includes materials or components losing their siffness beyond a certain degree.
Advanced Scientific and Engineering Services (AdvanSES) specializes in Fatigue Testing of Automotive Components including hoses, engine mounts, vibration isolators, silent bushes etc. Fatigue testing can be carried out in stress & force control, strain control or displacement control. The deformation modes under which fatigue tests are generally carried out are tension – tension, compression – compression, tension - compression and compression - tension.
Expert Fatigue Testing of Rubber, Elastomers, Polymers, Composites. Work with a true partner who understands your applications, creates the right testing setup, and adds value at every step of your material and product development cycle. AdvanSES has experience with metal, non-metals, polymers and rubbers and is a leading supplier to OEMs and Tier 1 suppliers worldwide.
Generating Fatigue Properties for Materials
A methodical procedure is used to generate the fatigue properties of materials. Generally 7 to 9 samples are tested at different stress levels. The stress levels and the testing is conducted so that by using progressively lower levels of stress, a stress value is obtained below which there are no failures. This stress level is termed as 'endurance limit' or 'fatigue limit' 0f the material.
The values of stress and the associated number of cycles at which failures occur at these levels is plotted on a graph and the plot is termed as an S-N Curve. For most steels the endurance limit is between 2.5 to 10 million cycles.
Graph below shows the S-N curve for Ferrous and Non-ferrous materials.
(Mark´s Standard- Handbook/Strength of Materials)
