Abstract. When a crack is present in a structure then the probability of failure of that structure is higher. Failure occurs when the natural frequency of the periodic force and the natural frequency of the structure are in a state of superposition. To avoid this phenomenon, it is essential to calculate the natural frequency. The aim of this study is to analyze the behavior of natural frequency for different parameters such as crack position, crack depth, crack opening and mesh sensitivity. In this study, the first five modes of vibration of both cracked and uncracked I beam has been extracted. A further analysis of resonance for a fixed vertical load has also been done. An amalgamation of hexahedral and wedge elements has been used to study the behavior of the cracked structure. As this is a problem of discontinuity, thus it is very troublesome to make a solution analytically. Therefore, ‘ABAQUS CAE’, one of the most popular finite element analysis software, was used for the analysis of cracke structure. The discoveries of this examination are that the presence of crack decreases the natural frequency of the beam, this decrease is identified with the position of the crack, its opening and its depth. Another finding of this examination is that the impact of vibration is huge for I beam when the break arrives at its web segment. It was also discovered that resonance happens before if the crack profundity is bigger or the existence of the crack is nearer to the fixed end.