ISSN: 2350-0328 International Journal of Advanced Research in Science, Engineering and Technology Vol. 3, Issue 1 , January 2016 Copyright to IJARSET www.ijarset.com 1266 Experimental and Finite Element Model Analysis of an un-cracked and cracked Cantilever beam Lanka Ramesh , P.Srinivasa Rao , K.Ch.Kishore Kumar, D.Kiran Prasad Assistant Professor, Mechanical Engineering Department, Gudlavalleru Engineering College, Sheshadri Rao Knowledge Village, Gudlavalleru- 521356 , Andhra Pradesh ,INDIA Professor, Mechanical Engineering Department, Andhra University, Visakha Patnam-530003,Andhra Pradesh Associate Professor, Mechanical Engineering Department, Gudlavalleru Engineering College, Sheshadri Rao Knowledge Village, Gudlavalleru- 521356, Andhra Pradesh ,INDIA Associate Professor, Mechanical Engineering Department, Gudlavalleru Engineering College, Sheshadri Rao Knowledge Village, Gudlavalleru- 521356, Andhra Pradesh ,INDIA ABSTRACT :Health monitoring and the analysis of damage in the form of crack in beam like structures are important not only for leading safe operation but also retraining system performance. Since long efforts are on their way to find a realistic solution for crack detection in beam structures in this regard many approaches have so far being taken place. When a structure suffers from damages, its dynamic properties can change and damage leads to reduction in stiffness also with an inherent reduction in natural frequency. The objective of this paper is to lend a viable relationship between the modal natural frequencies for the different crack depth for that vibration analysis is carried out on a cantilever beam with two open transverse cracks on universal vibration apparatus. Modelling and simulation is established using commercially available finite element analysis software package ANSYS.The results obtained from simulation are validated with the result obtained from the experiment. KEYWORDS: Experimental Modal Analysis, ANSYS, Cantilever Beam, Crack, Mode shape, Natural Frequency, universal vibration apparatus. I. INTRODUCTION It is required that structures must safely work during its service life. But, damages initiate a breakdown period on the structures. Cracks are among the most encountered damage types in the structures. Cracks in a structure may be hazardous due to static or dynamic loadings, so that crack detection plays an important role for structural health monitoring applications. Beam type structures are being commonly used in steel construction and machinery industries. The most common structural defect is the existence of a crack. Cracks are present in structures due to various reasons. The presence of a crack could not only cause a local variation in the stiffness but it could affect the mechanical behaviour of the entire structure to a considerable extent. Cracks may be caused by fatigue under service conditions as a result of the limited fatigue strength. They may also occur due to mechanical defects. Studies based on structural health monitoring for crack detection deal with change in natural frequencies and mode shapes of the beam. So in this paper develops viable relationship between natural frequency and mode shape at the different crack depth. In the past,. analytical expression for large amplitude free vibration of beam. They have also considered geometric non- linearity and have solved the expression using variational Iteration Method (VIM). Also the different nonlinear frequencies have been considered for different shapes of modes presented by Baghani, H. Mazaheri and H. Salarieh [1].study on variation of characteristics that are dependent on the amplitude of the functionally graded sandwich beams. The nonlinear characteristic of the material is also considered by applying it with the help of an exponential function. Also along with taking all this into consideration they have derived the governing equation of free vibration by means of finite element method carried by Allahverdizadeh, I. Eshraghi, M.J. Mahjoob and N. Nasrollahzadeh [2].Lianhua Wang, Jianjun Ma, JianPeng and Lifeng Li have investigated the nonlinear vibrations and the parametric instability of