Failure Analysis And Improvements Of A High Tower

With the emerging and development of broad-scale chemical enterprises, the number of towers with a high height-to-diameter ratio increases notably. As a result, the frequency of the tower vibration accidents induced by wind is quite high. This paper mainly focuses on the case that a 54 m high tower developed cracks, reveals the mechanism of the tower's damage. In particular, samples were taken from the cracked tower, and chemical composition analysis, mechanics performance testing, metallographic analysis and fracture analysis were carried out. Besides, modal analysis by software of ANSYS and corresponding fatigue stress calculation were also carried out in this paper.Analytically, it is found that coarse acicular and netted Widmanstaten structure appears at the welding line between head and skirt. Widmanstaten structure embrittles the material, increases the sensibility of weld seam cracking and let down the anti-fatigue ability of the weld seam notably. Besides, as wind-induced vibration happened, the tower developed cracks. Several measures are raised in the paper. It is advised that great attention should be attached to the control of the welding process during the repair, and low current and multi-pass welding are required. Besides, in order to reduce wind-induced vibration, it is also advised that flat roofs, ladders and pipes attached to towers should be installed as soon as possible.