عنوان البحث(Papers / Research Title)
Nonlinear Dynamic Characteristics of a Simple Blade with Breathing Crack Using Ansys Software
الناشر \ المحرر \ الكاتب (Author / Editor / Publisher)
نورس حيدر مصطفى أل سيد حيدر
Citation Information
نورس,حيدر,مصطفى,أل,سيد,حيدر ,Nonlinear Dynamic Characteristics of a Simple Blade with Breathing Crack Using Ansys Software , Time 5/5/2011 3:56:36 PM : كلية الهندسة
وصف الابستركت (Abstract)
البحث منشور في المجلة العالميه للميكانيك ( الولايات المتحدة الامريكية)
الوصف الكامل (Full Abstract)
Nonlinear Dynamic Characteristics of a Simple Blade with Breathing Crack Using Ansys SoftwareSalwan Obeed Waheed, Nawras Haidar Mostafa, Dhyai Hassan JawadMechanical Engineering Department, University of Babylon, Hilla, Iraq E-mail: bn.bn18@yahoo.com, nawras1980@gmail.com, dh_1970@yahoo.comReceived March 1, 2011; revised March 30, 2011; accepted April 2, 2011
Nonlinear dynamic response represents the most important studies for structures subjected to a dynamic mo-tion so that it provides the researcher by an excellent information especially at critical design levels. The un-predictable nonlinearity in the structure appears when damage is inherited. Most times, the failure of the structure is related to the dynamic nonlinearity. With regard to the breathing phenomena for nonlinear struc-tural systems, very little is known about how the nonlinearities influence the response and the dynamic char-acteristics of cracked structures. In this research, dynamic nonlinearity is presented in damaged structure due to presence of a crack. The crack is assumed to be open and close simultaneously and then breathing. Effect of breathing phenomenon was studied deeply. Crack breathing is simulated at the crack surfaces using con-tact elements. The contact, geometrical, penalty, and spin stiffnesses are taken in consideration. In addition, effect of several important parameters such as rotor angular velocity and crack ratio are studied. The study showed that the breathing natural frequency of any structure is ranged between opened (no contact) and closed crack natural frequencies. The larger crack length is, the more nonlinear disturbance in the dynamic response behavior. Also, at a critical crack length, some mode shapes tend to exchange and pass over with other modes. The presence of the mode interchanging and mode crossover was a guide on the nonlinear re-sponse for the cracked structure. The numerical modeling is achieved using ANSYS finite element program. Experimental data are used for validating the accurate use of contact elements in ANSYS environment.
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