What is BS 3518-1 – Methods of fatigue testing about?
BS 3518-1 standard is a part of the BS 3518 series that discusses the general principles for fatigue testing methods. Fatigue tests are performed to measure the reduction in stiffness and strength of materials under repeated loading and to determine the total number of load cycles to failure.
BS 3518-1 recommends the general principles to be followed in conducting fatigue tests on metallic materials. It gives definitions of recommended terms, guidance on the planning of the tests, and describes effective methods for the graphical presentation of the results. The forms of fatigue testing considered encompass both the use of uncracked and precracked test pieces; the former under either stress or strain control, and the latter under stress control and within the limits imposed by linear elastic fracture mechanics.
The general principles are presented initially in terms of the fatigue testing of plain test pieces under a constant amplitude loading in a normal laboratory environment. Subsequently, the general principles are extended to include additional concepts and recommendations associated with the testing of notched test pieces or structural components, testing in different environments and testing under variable amplitude loadings.
Note: BS 3518-1 does not cover the welded test pieces.
Who Is BS 3518-1 – Methods of fatigue testing for?
BS 3518-1 on the fatigue testing methods applies to:
- Manufacturer of fatigue testing machine
- Quality testing personnel
- Engineers
Why should you use BS 3518-1 – Methods of fatigue testing?
Fatigue relates to the initiation and growth of cracks in metallic materials due to the repeated application of mechanical stresses or strains and any associated changes in mechanical properties. The term stress control is used to describe tests in which the force acting on a known specimen cross-sectional area is controlled, whilst strain control refers to tests in which the displacement of an extensometer of known gauge length is controlled.
BS 3518-1 provides various types of test programmes for fatigue testing which include: Stress controlled testing in which the objectives containing are:
- To obtain a well-defined S/N fatigue curve for design
- To determine the fatigue strength at a specified life
- To determine whether a change of material or surface treatment affects fatigue resistance
- To accept or reject material for manufacturing purposes
- To answer questions posed by a service failure.
Strain controlled in which the objective of this test is to determine the total strain amplitude versus fatigue life relationship for material, either in an exploratory manner or to generate data for design purposes. BS 3518-1 also includes crack growth testing, notched specimen testing, variable amplitude testing and component testing which helps you in the method for fatigue testing.
BS 3518-1 provides you with comprehensive guidance useful throughout the process of fatigue testing.
