Tham khảo tài liệu 'failure analysis case studies ii episode 8', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | 233 Axial coil Transverse coil a 1 2 inch flange size Axial coil Transverse coil Frequency Hz b 1 inch flange size Fig. 10. Frequency response of node 33 showing peak displacement for the transverse and axial coil configurations. 234 Table 2. Natural frequencies for 1 in. flange connections with axial coil showing the effects of reducing tube height and flange size A infield configuration B modified configuration Mode A B 1 2 3 4 5 6 7 8 9 10 REFERENCES 1. Al-Asmi K. Seibi A. Samanta B. and Siddiqui R. Investigation into the Failure of Pressure Transmitter Impulse Line. Sahma Booster Station Internal Report ME SQU July 1995. 2. Callistcr Jr w. D. Materia Science and Engineering An Introduction 3rd ed. John Wiley Sons Inc. 1994. 3. Hertzberg R. w. Deformation and Fracture Mechanics of Engineering Materials 2nd ed. John Wiley Sons Inc. 1983. 4. Shtgley J. s. and Mischke c. R. Mechanical Engineering Design 5th ed. McGraw-Hill 1989. F ailure Analysis Case Studies ll . Jones Editor 2001 Elsevier Science Ltd. All rights reserved 235 MALFUNCTIONS OF A STEAM TURBINE MECHANICAL CONTROL SYSTEM J. H. BULLOCH and A. G. CALLAGY Power Generation ESB. Lower Fitzwilliam Street Dublin 2 Ireland Received 13 October 1997 Abstract This paper is aimed at elucidating the cause of a series of malfunctions involving the bending or breaking of main steam turbine throttle valve spindles which occurred at service times ranging from hundreds to several thousand hours in a number of 270 MW steam raising units. It was clearly established by two distinct approaches one engineering one micromechanistic that the stresses which produced these malfunctions were bending in nature and were the result of out-of alignment deflections. In the case of the bent spindles the stresses were very high and approached flow strength levels of around 8000 MPa while the broken spindles were the .
