Abstract

In this research development the derivation of general equation of motion for beam with crack effect presented in paper [1], to derivation the general equation of motion of beam with oblique crack effect. The derivation of equation of motion of beam included suggested analytical solution for effect of oblique in crack on the natural frequency of beam with added the effect oblique of crack in stiffness (EI) beam with calculated the equivalent stiffness, (EI), for a rectangular beam to involve an exponential function with depth, location and ordination of oblique crack effect, with solution of assuming equivalent stiffness beam (EI) by using of Fourier series method. The natural frequency of a cracked beam with simply supported beam is investigated analytically, with solution of general equation of motion of beam with oblique crack effect, and numerically by finite element method, with using of ANSYS program ver. 14, for different crack depth, location and crack orientation effect and the results are compared. The same beam materials studied in paper, [1], are study in this research as, low carbon steel, Alloys Aluminum, and Bronze materials with different beam length, depth and crack orientation. A comparison made between analytical results from theoretical solution of general equation of motion of beam with oblique crack effect with numerical solution by finite element method with using ANSYS results, where the biggest error percentage is about (1.8 %). The results of natural frequency of beam shows that the natural frequency of beam increasing with increasing the crack orientation, the effect of crack orientation decreasing with increase the orientation of crack.