Papers by Keyword: Creep Strain

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Authors: Mohammed Ali Morovat, Jin Woo Lee, Michael D. Engelhardt, Eric M. Taleff, Todd A. Helwig, Victoria A. Segrest
Abstract: In moving towards an engineered performance-based approach to structural fire safety, a sound knowledge of the elevated-temperature properties of structural steel is crucial. Of all mechanical properties of structural steel at elevated temperatures, material creep is particularly important. Under fire conditions, behavior of steel members and structures can be highly time-dependent. As a result, understanding the time-dependent mechanical properties of structural steel at high temperatures becomes essential. This paper presents preliminary results of a comprehensive on-going research project aimed at characterizing the material creep behavior of ASTM A992 steel at elevated temperatures. Such creep properties are presented in the form of strain-time curves for materials from the web and the flanges of a W4×13 wide flange section and from the web of a W30×99 section. The test results are then compared against material creep models for structural steel developed by Harmathy, and by Fields and Fields to evaluate the predictions of these models. The preliminary results clearly indicate that material creep is significant within the time, temperature, and stress regimes expected in a builing fire. The results also demonstrate the need for a more reliable creep model for steel for strcutural-fire engineering analysis.
Authors: F. Masuyama, M. Matsui, N. Komai
Authors: Karen M. Taminger, John A. Wagner, W. Barry Lisagor
Authors: T. Muraki, Yuki Hasegawa, M. Ohgami
Authors: Khairul Azhar Mohammad, Edi Syam Zainudin, S.M. Sapuan, Nur Ismarrubie Zahari, Ali Aidy
Abstract: The aim of this study is to investigate the creep test on static loading of stainless steel materials. Theestablished creep analytical modeling was used to predict the creep life of stainless steel at high temperature. In order to conduct creep testing, the materials were subjected to constant load and high temperature at 565°Cin comparisons with different stresses at the similar temperatures.Time dependent deformation of 316L stainless steel at high temperature at different loading was investigated in this study.The variationof creep strain rates is clearly shown that the secondary creep obeyed and well agreement with a power law relationship as the constant increase creep rate till the tertiary stages of specimen test.
Authors: Andrew Morris, John P. Dear, Miltiadis Kourmpetis, Chris Maharaj, Amit Puri, Alexander D. Fergusson
Abstract: Cost effective and reliable operation of a power station plant and achieving low carbon dioxide emissions can be very dependent on maintenance activities. Planning maintenance to minimise the down-time of the plant is a key cost factor. It is important to have the latest data as to the age and state of the components and parts at the time of plant shut down. Indeed, deciding on the best time to shut down the plant for maintenance can depend upon trends in these data. For steam pipes, the required ageing information is the creep strain rate. These creep strain data obtained at shut down provide key information as to the needed replacement of pipes to maintain reliable plant operation. This paper presents the E.ON UK ARCMAC creep strain measurement systems that are being further developed by Imperial College London with the use of DIC and other techniques.
Authors: Ling Cheng, Zheng Nan Chen, Jian Gao
Abstract: By the finite element analysis codes ABAQUS and the function of RESTART, a sequential coupling calculating program for creep based on welding residual stress has been developed by establishing the model of temperature field, residual field and creep analysis. The welding residual stress and creep of welded joint for Cr5Mo furnace tubes was simulated by the program. This method established the basis for calculating the effects of welding residual stress on the creep of welded joint. A creep comparison between the welded joint tubes with welding residual stress and with internal pressure was made in the paper. The results show that although the residual stress is greatly decreased due to the creep relaxation behavior at high temperature, the initial welding residual stress has a great influence on the tube creep. The research results provide a reference for strength design of high temperature components.
Authors: Andina Sprince, Aleksandrs Korjakins, Leonids Pakrastinsh
Abstract: This research deals with experimentally studied time-dependent deformations of polyvinyl alcohol (PVA) fiber reinforced high performance concrete (HPFRC). The creep in compression and crack propagation of the new concrete compositions were determined. Several kind of concrete mixes adding microsilica and nanosilica have been made. For each composition cylinders with dimensions 190x47mm and Compact Tension (CT) specimens with dimensions 150x150x12mm were prepared. Concrete specimens were tested in a controlled constant temperature and with a constant level of moisture. Creep specimens were put into a creep lever test stand and subjected to a uniform, constant compressive load but CT specimens were subjected to a tension load. Deformations and crack mouth opening displacements were measured with extensometers. The compression strength and modulus of elasticity also were determined. The results have shown that nanosilica dont have significant influence on the high performance fiber reinforced concrete time-dependent behavior.
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