Effect of creep characteristics on pipeline durability

• Autorzy: Mutwil K.
• Języki publikacji: EN

Abstrakty

EN

Purpose: The paper presents an assessment of durability of a steam pipeline operating above the threshold temperature. The durability calculations take into account the creep characteristics of the material. Design/methodology/approach: The results of calculations of the degree of wear caused by the creep of a pipeline, made using numerical methods, are presented. The calculation model takes into consideration the basic geometric and material properties of the pipeline, its operating parameters, and the displacement of valve and turbine chambers which force an initial displacement of the pipeline in the cold state. Findings: As a result of the calculations made, the effect of redistribution and relaxation of stresses induced by the initial guy wire tension has been found. This leads to a rapid loss of stresses, the consequence of which is enhanced durability of the investigated object. Research limitations/implications: Due to the lack of data regarding objects operated for a long time, the calculations of their durability made under this study provide preliminary information on the expected further operational life of a specific structural element. The comprehensive evaluation of the life of an object should be supplemented by research on the material to enable determining the actual degree of material wear in the areas of the analyzed element subject to the highest effort. Practical implications: To ensure operational safety of pipelines operated for a long time, a method is presented to evaluate their durability, which takes into account the effect of additional loads on the effort of the pipeline. Originality/value: In the calculations of wear caused by creep, carried out in line with the EN-13480 standard, the criterion is the stress in the wall of a component under internal pressure. The paper presents the results of stress calculations while taking account of additional operational load, which has a significant influence on the degree of material wear.

Słowa kluczowe

EN

pipeline durability; material creep; calculation model; numerical methods; stress relaxation

• Wydawca: International OCSCO World Press
• Czasopismo: Journal of Achievements in Materials and Manufacturing Engineering
• Rocznik: 2011
• Tom: Vol. 48, nr 1
• Strony: 97--102
• Opis fizyczny: Bibliogr. 15 poz., rys.

Twórcy

autor

Mutwil K.

• Department of Materials Technology, Faculty of Materials Science and Metallurgy, Silesian University of Technology, ul. Krasińskiego 8, 40-019 Katowice, Poland

Bibliografia

• [1] PN-EN 13480-3. Industrial metal pipelines. Part 3: Design and calculations.
• [2] Technische Reglen fur Damfkessel -TRD 301 Anl.1 Ausg 4.75 (in German).
• [3] Technische Reglen fur Damfkessel -TRD 508 Anl.1 Ausg 6.86 (in German).
• [4] K. Mutwil, J. Okrajni, Forecasting of the durability of energy objects with the use of the numerical modelling, Gloryhole Mining 4-5 (2008) (in Polish).
• [5] J. Okrajni, K. Mutwil, M. Cieśla, The durability and the security of the exploitation of pipelines of intermediate WP and SP on the example of the turbine 18K360, Proceedings of the 7th Conference Scientifically Technical „Thermal Power Stations - The exploitation, Modernizations, Overhauls” Słok, 2005 (in Polish).
• [6] C.C. Spyrakos, Finite Element Modeling in Engineering Practice, West Virginia University Morgantown, 1994.
• [7] T. Łodygowski, W. Kakol, The finite element method in chosen issues of the mechanics of the construction, Poznan Technical University Publishing House, 2003 (in Polish).
• [8] H. Kraus, Creep Analysis, John Wiley & Sons Inc., New York, 1990.
• [9] A. Hernas, J. Dobrzański, The durability and the deterioration of elements of boilers and steam turbines, Silesian University of Technology Publishing House, Gliwice, 2003 (in Polish).
• [10] A. Tjan, Y. Adrian, Analysis of creep properties of bituminous mixture with constant rate of load increment method, Eastern Asia Society for Transportation Studies, Indonesia, vol. 4, 2003.
• [11] J. Skrzypek, Plasticity and the creep. The Theory, Uses, Tasks, PWN, Warsaw, 1986 (in Polish).
• [12] Characteristics obtained thanks to courtesy of Engineer J. Dobrzański, Ph.D. from the Institute for Ferrous Metallurgy, Gliwice.
• [13] PN-EN 12952-4. Part 1: Water-tube boilers and auxiliaries. Part 4: Calculations of boiler durability expectancy in service.
• [14] M. Bielecki, J. Badur, The computer expectation of the durability of steam-pipelines, IMP PN, 2003 (in Polish).
• [15] M. Bielecki, The implementation of the model of the creep with the destruction in FEM, IMP PN, 2004 (in Polish).