PSI - Issue 18

Available online at www.sciencedirect.com Available online at www.sciencedirect.com ScienceDirect StructuralIntegrity Procedia 00 (2019) 000–000 Available online at www.sciencedirect.com ScienceDirect StructuralIntegrity Procedia 00 (2019) 000–000

www.elsevier.com/locate/procedia www.elsevier.com/locate/procedia

ScienceDirect

Procedia Structural Integrity 18 (2019) 406–412

25th International Conference on Fracture and Structural Integrity Failure analysis of a crane gear shaft Goran Vukelic a , D. Pastorcic b *, G. Vizentin a a University of Rijeka, Faculty of Maritime Studies, Marine Engineering Department, Studentska 2, 51000 Rijeka, Croatia bUniversity of Zadar, Maritime Department, Zadar, Croatia 25th International Conference on Fracture and Structural Integrity Failure analysis of a crane gear shaft Goran Vukelic a , D. Pastorcic b *, G. Vizentin a a University of Rijeka, Faculty of Maritime Studies, Marine Engineering Department, Studentska 2, 51000 Rijeka, Croatia bUniversity of Zadar, Maritime Department, Zadar, Croatia

Abstract This research deals with a teeth failure of a gear shaft that served as a part of shipyard crane drive train. Almost all of the teeth of a spiral bevel gear, part of a larger shaft, fractured during normal operation of the crane. Failure analysis combined experimental and numerical research. Visual inspection was employed to determine the fracture location and crack propagation paths. Microscopy, optical and scanning electron (SEM), was used to inspect damaged surfaces of the teeth, reveal possible flaws and fine microstructure of the material. Type of steel used for manufacturing was determined based on chemical composition of the material obtained using optical emission spectrometer with glow discharge source (GDS) sample stimulation. Further, tensile specimens were extracted from the shaft to test the strength of the steel. Additionally, hardness test was performed. All experimental research suggest it is a case of gear teeth spalling, probably caused by excessive contact stresses. To gain better understanding of the failure process, a 3D numerical model of the gear shaft was built and finite element (FE) stress analysis performed. Analysis showed excessive contact stresses at the teeth contact area. Time-varying meshing stiffness (TVMS), an important gear health condition parameter, is determined via FE procedure for several examples of healthy to gradually damaged gear. Obtained results show how spall propagation influences TVMS and, thus, affects gear performance leading to potential failure. Abstract This research d ls with a teeth failure of a gear shaft that served as a part of shipyard crane drive train. Almost all of th teeth of a spiral bevel gear, part of a larger shaft, fractured during normal operation of the crane. Failure analysis combined experimental and numerical research. Visual inspection was employed t determine the fracture location and crack propagation paths. Micros opy, optical and scanning electron (SEM), was used to inspect damaged surfac s of the teeth, reveal possible flaws and fine micr structure of the material. Type of steel used for manufacturing was determined based on che ical composition of th material obtained using optical emission spectrometer with glow discharge source (GDS) sample stimulation. Further, tensile specimens were extracted from the shaft to test the strength of the steel. Additionally, hardness test was performed. All xperimental research suggest it is a case of ge r teeth spalling, probably caused by excessive contact stresses. To g in better understanding of t e failure process, a 3D numerical model of the ge r shaft was built and finite element (FE) stress analysis performed. Analysis showed excessive contact stress s at the teeth contact ar a. Time-varying meshing stiffness (TVMS), an important gear health conditi n par meter, is determined via FE procedure for sev ral ex mples of healthy to gradually damaged gear. Obtained results show how spall propagation influences TVMS and, thus, affects gear performance leading to potential failure.

© 2019 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Gruppo Italiano Frattura (IGF) ExCo. © 2019 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Gruppo Italiano Frattura (IGF) ExCo. © 2019 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Gruppo Italiano Frattura (IGF) ExCo.

Keywords: gear; bevel gear; crane gear shaft; failure analysis Keywords: gear; bevel gear; crane gear shaft; failure analysis

* Corresponding author. Tel.: 0038598891042. E-mail address: dpastorci@unizd.hr * Correspon ing author. Tel.: 0038598891042. E-mail address: dpastorci@unizd.hr

2452-3216© 2019 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Gruppo Italiano Frattura (IGF) ExCo. 2452-3216© 2019 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Gruppo Italiano Frattura (IGF) ExCo.

2452-3216  2019 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Gruppo Italiano Frattura (IGF) ExCo. 10.1016/j.prostr.2019.08.182