FEM MODAL ANALYSIS FOR DAMAGE DETECTION IN AIRPLANE STRUCTURES

Technics for damage and fatigue detection has become an essential part of Aeronautic industry safety. The duration of service lives of such vehicles can be considerably extended by systematic monitoring of small, possibly undetected, damages to their structures. In this paper, we propose damage detection in airplane structures via modal analysis. By using Finite Element Method numerical models, developed in commercial software, as a first step, we make comparisons of the free vibration frequencies of undamaged models and models where we deliberately introduce damage. We observe the difference in frequency values. In future work we will propose numerical damage indicators based on the modal analysis. Keywords: Aeronautical Structure, Damage Detection, Modal Analysis, FEM

Warthin's Tumour Of The Parotid Gland: Our Experience [tumori Di Warthin Della Ghiandola Parotide: Nostra Esperienza]

Benign tumours account for approximately 60-80% of parotid neoplasms and among these, Warthin's tumour is the second most common benign neoplasm accounting for approximately 15% of all parotid epithelial tumours. The medical records of 100 consecutive patients with Warthin's tumour of the parotid gland admitted for treatment at the Department of Head and Neck Surgery and Otorhinolaryngology, Hospital A.C. Camargo, São Paulo, Brazil, between 1983 and 2011 were retrospectively analyzed. The surgical procedures included 104 (96%) subtotal parotidectomies and 4 (3.7%) total parotidectomies. One hundred and eight parotidectomies were performed in 100 patients with Warthin's tumour. Postoperative complications occurred in 67 (62.3%) of surgical procedures, and facial nerve dysfunction was the most frequent complication, occurring in 51 of 108 surgeries (47.2%). The marginal mandibular branch of the facial nerve was affected in 46 of the 48 cases (95.8%) of facial nerve dysfunction. Frey's syndrome was diagnosed in the late postoperative period in 19 patients (17.6%). We conclude that either superficial or total parotidectomy with preservation of facial nerve are the treatment of choice for Warthin's tumour with no case of recurrence seen after long-term follow-up. Facial nerve dysfunction and Frey's syndrome were the main complications associated with this surgery. Thus, if on one hand total parotidectomy is an appropriate radical resection of parotid parenchyma reducing, in theory, the risk of recurrence, on the other hand superficial parotidectomy is also a radical and efficient method with lower morbidity in terms of facial nerve dysfunction and Frey's syndrome.336393397Freedman, L.S., Oberman, B., Sadetzki, S., Using time-dependent covariate analysis to elucidate the relation of smoking history to Warthin's tumor risk (2009) Am J Epidemiol, 170, pp. 1178-1185Bussu, F., Parrilla, C., Rizzo, D., Clinical approach and treatment of benign and malignant parotid masses, personal experience (2011) Acta Otorhinolaryngol Ital, 31, pp. 135-143Barnes, L., Eveson, J.W., Reichart, P., Pathology and genetics, head and neck tumours (2005) World Health Organization classification of tumors., pp. 209-281. , In: Lyon: IARC PressNeville, B.W., Damm, D.D., Allen, C.M., Salivary Gland Pathology (2009) Oral and Maxillofacial Pathology., 11, pp. 461-462. , In: 3rd ed. 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The anatomicoclinical, diagnostic and therapeutic aspects of 2 cases. Review. Italian (1994) Minerva Stomatol, 43, pp. 535-542Ascani, G., Pieramici, T., Rubini, C., Synchronous bilateral Warthin's tumours of the parotid glands: A case report (2010) Acta Otorhinolaryngol Ital, 30, pp. 310-312Baj, A., Beltramini, G.A., Demarchi, M., Bilateral SMAS rhytidectomy in parotid recurrent pleomorphic adenoma (2011) Acta Otorhinolaryngol Ital, 31, pp. 256-258Arida, M., Barnes, E.L., Hunt, J.L., Molecular assessment of allelic loss in Warthin tumors (2005) Mod Pathol, 18, pp. 964-968García Purrinõs, F.J., Thirteen years' experience with superficial partial parotidectomy as treatment for benign parotid tumours (2011) Acta Otorrinolaringol Esp, 62, pp. 10-13Rigante, M., Visocchi, M., Petrone, G., Synovial sarcoma of the parotid gland: A case report and review of the literature (2011) Acta Otorhinolaryngol Ital, 31, pp. 43-46Koch, M., Zenk, J., Iro, H., Long-term results of morbidity after parotid gland surgery in benign disease (2010) Laryngoscope, 120, pp. 724-730Upton, D.C., McNamar, J.P., Connor, N.P., Parotidectomy: Ten-year review of 237 cases at a single institution (2007) Otolaryngol Head Neck Surg, 136, pp. 788-792Yuan, X., Gao, Z., Jiang, H., Predictors of facial palsy after surgery for benign parotid disease: Multivariate analysis of 626 operations (2009) Head Neck, 31, pp. 1588-1592Govindaraj, S., Cohen, M., Genden, E.M., The use of acellular dermis in the prevention of Frey's syndrome (2001) Laryngoscope, 111 (11 PART 1), pp. 1993-1998de Bree, R., van der Waal, I., Leemans, C.R., Management of Frey syndrome (2007) Review. Head Neck, 29, pp. 773-778Bron, L.P., O'Brien, C.J., Facial nerve function after parotidectomy (1997) Arch Otolaryngol Head Neck Surg, 123, pp. 1091-1096Gaillard, C., Peries, S., Susini, B., Facial nerve dysfunction after parotidectomy: The role of local factors (2005) Laryngoscope, 115, pp. 287-291Eisele, D.W., Wang, S.J., Orloff, L.A., Electrophysiologic facial nerve monitoring during parotidectomy (2010) Head Neck, 32, pp. 399-405Nouraei, S.A., Ismail, Y., Ferguson, M.S., Analysis of complications following surgical treatment of benign parotid disease (2008) ANZ J Surg, 78, pp. 134-138Filho, W.Q., Dedivitis, R.A., Rapoport, A., Sternocleidomastoid muscle flap preventing Frey syndrome following parotidectomy (2004) World J Surg, 28, pp. 361-364Sanabria, A., Kowalski, L.P., Bradley, P.J., Sternocleidomastoid muscle flap in preventing Frey's syndrome after parotidectomy: A systematic review (2012) Head Neck, 34, pp. 589-59