Fatigue investigations on a forged “W-Link” to improve the transferability of specimen results to real components

AbstractTo improve computational lifetime calculation methods, a component specimen named “W-Link” is generated from the Ti-alloy Ti-6Al-4V. Based on specimen tests, S/N-curves were evaluated and integrated in the lifetime calculation program FEMFAT. Whereby, life time estimation for the component is made possible. In order to compare lifetime calculation to lifetime in reality, component tests were carried out. In this way not only the simulation of the lifetime and real tests on specimens are shown, also the transferability of specimen results to component is presented. Finally, fracture analysis and comparison of the different specimens is carried out

INVESTIGATIONS TO IMPROVE THE TRANSFERABILITY OF SPECIMEN RESULTS BY REAL COMPONENT

For the improvement of the lifetime calculation of components made of the titanium alloy Ti-6-4, a closed loop methodology from specimen to the component is presented. Based on forged pre-material specimens fatigue tests are done as a basic research, which are presented as S/N-curves. With the determined material data a lifetime calculation with the program FEMFAT is done on a typically fitting element. Finally the results of the lifetime calculation are compared to real component tests, which are done to evaluate the results of the lifetime calculation. The component tests are performed with constant and variable load. Therewith the transferability of specimen results to real components is shown. Additional fracture analysis by light microscope and scanning electron microscope is carried out to give further information of the influence factor of the lifetime and a further description between fracture behaviour of specimen and components

Material and component investigations on a Ti-6-4 fitting element

An improvement in the life time calculation is aspired by the characterisation of the life time behaviour of a typically lightweight aircraft titanium alloy by describing the microstructure. Therefore, extensive research on a Ti-6-4 fitting element has been carried out. In addition to static tensile tests, rotating bending tests and fracture mechanical tests, component tests with constant and variable load were performed. Simultaneously, the microstructures of the specimens and tested components are extensively analysed at several points including the lug area, as well as, the specimen’s microstructure taken out of the lower link fitting. A common consideration of life time results as well as results of the microstructure in the life time calculation shows the possibilities for more precise life time estimation