Abstract
Complex stresses, which occur on the mechanical surfaces of transport machinery in service, bring a drastic degradation in fatigue life. However, it is hard to reproduce such complex stress states for evaluating the fatigue life with conventional multiaxial fatigue machines. We have developed a fatigue testing machine that enables reproduction of such complex stresses. The testing machine can reproduce arbitrary in-plane stress states by applying three independent loads to the test specimen using actuators which apply loads in the 0, 45, and 90 degree directions. The reproduction was tested with complex stress data obtained from the actual operation of transport machinery. As a result, it was found that the reproduced stress corresponded to the measured stress with an error range of less than 10 %. Then, we made a comparison between measured fatigue lives under random non-proportional loading conditions and predicted fatigue lives. It was found that predicted fatigue lives with ?cr, stress on critical plane, were over a factor of 10 against measured fatigue lives. On the other hand, predicted fatigue lives with ?ma, stress in consideration of a non-proportional level evaluated by using amplitude and direction of principal stress, were within a factor of 3 against measured fatigue lives. KEYWORDS. Fatigue; Non-proportional; Random; Plane stress; Fatigue life prediction; Testing machine.
Highlights
The main objective of this study is to develop a fatigue testing machine that enables reproduction of complex stresses occurring on the mechanical surfaces of transport machinery in service such as automobiles and railway vehicles
We have developed a fatigue testing machine that enables generation of arbitrary in-plane stress states which occur on a mechanical surface where fatigue crack initiates
Fatigue testing results under non-proportional loading conditions We made a comparison between measured fatigue lives and predicted fatigue lives under random non-proportional loading conditions
Summary
The main objective of this study is to develop a fatigue testing machine that enables reproduction of complex stresses occurring on the mechanical surfaces of transport machinery in service such as automobiles and railway vehicles. It is well-known that non-proportional loading generating such complex stresses brings a drastic degradation in fatigue life [1, 2]. It is hard to reproduce such complex stress states with conventional multiaxial fatigue testing machines. We have developed a fatigue testing machine that enables generation of arbitrary in-plane stress states which occur on a mechanical surface where fatigue crack initiates. Fatigue tests under random non-proportional loading conditions were performed with the advanced tasting machine
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
