Experimental and numerical investigation on the influence of a large crack on the modal behaviour of a Kaplan turbine blade
A large crack was discovered on one blade of a Kaplan turbine prototype after the inspection of the machine. In order to know the origin of the crack, a failure analysis was previously carried out (Zhang et al., 2019). To know the modal behaviour of cracked structures is of interest in order to dete...
| Autores: | , , , , , |
|---|---|
| Tipo de recurso: | artículo |
| Fecha de publicación: | 2020 |
| País: | España |
| Institución: | Universitat Politècnica de Catalunya (UPC) |
| Repositorio: | UPCommons. Portal del coneixement obert de la UPC |
| Idioma: | inglés |
| OAI Identifier: | oai:upcommons.upc.edu:2117/375160 |
| Acceso en línea: | https://hdl.handle.net/2117/375160 https://dx.doi.org/10.1016/j.engfailanal.2020.104389 |
| Access Level: | acceso abierto |
| Palabra clave: | Hydraulic turbines Kaplan turbine Crack monitoring Modal behaviour Turbines hidràuliques Àrees temàtiques de la UPC::Enginyeria mecànica::Mecànica de fluids |
| Sumario: | A large crack was discovered on one blade of a Kaplan turbine prototype after the inspection of the machine. In order to know the origin of the crack, a failure analysis was previously carried out (Zhang et al., 2019). To know the modal behaviour of cracked structures is of interest in order to detect the crack while in operation. For this purpose, an experimental and numerical investigation of the damaged blade and of another non-damaged blade was performed. Results of natural frequencies and mode-shapes of both blades have been compared in order to identify the main differences in modal behaviour when a crack appears. The crack was so large than one part of the blade was deformed by its own weight, causing contact between the two surfaces of the crack. This fact gives an additional stiffness to the crack, which should be considered in the numerical models. For that, a stiffness change in this zone was included. The influence of this stiffness on the natural frequency values and mode-shapes has been studied in detail. In that way, a numerical model for estimating the modal behaviour of large cracks have been implemented and validated. |
|---|