Stiffness variation due to cracks in rotors is a well-known problem; plenty of studies to prevent/avoid catastrophic accidents and rotor bursts exist. FEM numerical results calculating natural modal frequencies for open cracked beams at different notch depths and slenderness ratios, are compared versus experimental laboratory measurements. Shaft beams under simply supported and free-free boundary conditions, focusing on solids and Timoshenko beam finite elements, are studied. Timoshenko beams employ the Mayes and Davies equivalent-length concept for crack modeling. Notched shafts provide useful upper bound frequency reductions values (breathing cracks display up to, and smaller decrements). Modal frequency splitting for each natural frequency are confirmed and validated by numerical simulation and tests. Modal frequencies splitting functions are given, obtained by simulation and experiments which reflect strong crack depth and slenderness ratio influences. Vibrational coupling energy of the frequency splitting reaches a maximum when the excitation is orthogonal to the crack orientation, conclusions are given.

Experimental and Numerical Analysis of Transversal Open Cracked Shafts Considering Beam Slenderness and Crack Depth

BREGANT, LUIGI
2015

Abstract

Stiffness variation due to cracks in rotors is a well-known problem; plenty of studies to prevent/avoid catastrophic accidents and rotor bursts exist. FEM numerical results calculating natural modal frequencies for open cracked beams at different notch depths and slenderness ratios, are compared versus experimental laboratory measurements. Shaft beams under simply supported and free-free boundary conditions, focusing on solids and Timoshenko beam finite elements, are studied. Timoshenko beams employ the Mayes and Davies equivalent-length concept for crack modeling. Notched shafts provide useful upper bound frequency reductions values (breathing cracks display up to, and smaller decrements). Modal frequency splitting for each natural frequency are confirmed and validated by numerical simulation and tests. Modal frequencies splitting functions are given, obtained by simulation and experiments which reflect strong crack depth and slenderness ratio influences. Vibrational coupling energy of the frequency splitting reaches a maximum when the excitation is orthogonal to the crack orientation, conclusions are given.
978-3-319-06589-2
File in questo prodotto:
File Dimensione Formato  
iftomm_garciamancillabregant.pdf

non disponibili

Descrizione: articolo
Tipologia: Documento in Versione Editoriale
Licenza: Digital Rights Management non definito
Dimensione 341.08 kB
Formato Adobe PDF
341.08 kB Adobe PDF   Visualizza/Apri   Richiedi una copia

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/11368/2841559
Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus 1
  • ???jsp.display-item.citation.isi??? ND
social impact