On the generation of a loading history with zero mean for structures subjected to multiaxial variable stresses

2010-06-07
When a component is subjected to an excitation that has a nonzero mean, this mean value could have a noteworthy effect on the stresses and thus on the fatigue life of the component. In fatigue calculations, mean stress effect can be taken into consideration rather easily but experimental verification is troublesome since with traditional testing equipment like vibration shakers, any mean value of an acceleration excitation other than 1g in the direction of gravity is difficult to simulate. In this study, a method is proposed to create a modified input loading history with a zero mean which causes fatigue damage approximately equivalent to that created by input loading with a nonzero mean. For this purpose, a mathematical procedure is developed to apply three dimensional mean stress correction to the output stress power spectral density data. A modified input acceleration power spectral density is generated by means of transfer functions calculated via frequency response analysis. In the implementation of the developed method, a plate subjected to base excitation is considered. The base excitation leads to a fully three dimensional multiaxial state of stress in the plate. It is shown that the developed method is useful in creating a modified input acceleration data with a zero mean that can simulate damage for a selected point in the structure under consideration. Equivalent input loading obtained by means of the aforementioned method is convenient for experimental applications. Besides being a time saving method, it is suitable to be implemented for any type of loading.
Citation Formats
B. Kocer, Y. Yazıcıoğlu, and S. Dağ, “On the generation of a loading history with zero mean for structures subjected to multiaxial variable stresses,” presented at the 9th International Conference on Multiaxial Fatigue and Fracture (ICMFF2010), Parma, Italy, 2010, Accessed: 00, 2021. [Online]. Available: https://hdl.handle.net/11511/75709.