EFFECT OF CRACK DEPTH ON THE NATURAL FREQUENCY OF A PRESTRESSED FIXED-FIXED BEAM

The effect of crack depth on the transverse vibrational characteristic s of a prestressed fixed-fixed beam is investigated. The natural frequ ency of the system is obtained by modal analysis. The coupling effect between the crack depth and the axial load on the natural frequency of the system is investigated. Also, experimental work verifies the resu lts of the theoretical analysis. The study shows that there is a signi ficant coupling between the axial load and the crack depth, and this c oupling effect is directly proportional to the crack depth as well as the axial load. Therefore, the problem of a prestressed cracked beam c annot be treated as a superposition of two separate effects (crack plu s axial load) to find the natural frequency of the system. (C) 1998 Ac ademic Press.