scholarly journals Biaxial creep-fatigue behavior of materials for solar thermal systems

1980 ◽  
Author(s):  
S. Majumdar
Keyword(s):  
Fatigue Behavior ◽  
Solar Thermal ◽  
Thermal Systems ◽  
Creep Fatigue ◽  
Biaxial Creep

Biaxial Cyclic Deformation and Creep-Fatigue Behavior of Materials for Solar Thermal Systems

1982 ◽  
Vol 104 (2) ◽  
pp. 88-95 ◽  
Author(s):  
S. Majumdar
Keyword(s):  
Stainless Steel ◽  
Internal Pressure ◽  
Cyclic Deformation ◽  
Fatigue Behavior ◽  
Axial Stress ◽  
Thermal Systems ◽  
Creep Fatigue ◽  
Incoloy 800 ◽  
The Difference ◽  
Tubular Specimens

Biaxial cyclic deformation and creep-fatigue data for Incoloy 800 and Type 316H stainless steel at elevated temperature are presented. Tubular specimens were subjected to constant internal pressure and strain-controlled axial cycling with and without hold times in tension as well as in compression. The results show that the internal pressure affects diametral ratchetting and axial stress range significantly. However, the effect of a relatively small and steady hoop stress on the cyclic life of the materials is minimal. A 1-min compressive hold per cycle does not seriously reduce the fatigue life of either material; a tensile hold of equal duration causes a significant reduction in life for Type 316H stainless steel, but none for Incoloy 800. Fracture surfaces of specimens made of both materials were studied by scanning electron microscopy to determine the reason for the difference in behavior.

Environmental assessment of solar thermal systems for the industrial sector

2018 ◽  
Vol 176 ◽  
pp. 99-109 ◽  
Author(s):  
Angeliki Kylili ◽  
Paris A. Fokaides ◽  
Andreas Ioannides ◽  
Soteris Kalogirou
Keyword(s):  
Environmental Assessment ◽  
Industrial Sector ◽  
Solar Thermal ◽  
Thermal Systems

Component Low Cycle Fatigue Behavior Based on Standard Calculation Procedure and Non-Linear FEA

2017 ◽  
Author(s):  
Jürgen Rudolph ◽  
Adrian Willuweit ◽  
Steffen Bergholz ◽  
Christian Philippek ◽  
Jevgenij Kobzarev
Keyword(s):  
Power Plants ◽  
Low Cycle Fatigue ◽  
Fatigue Behavior ◽  
Hybrid Approach ◽  
Combined Cycle ◽  
Cycle Fatigue ◽  
Element Analysis ◽  
Constitutive Material Model ◽  
Standard Design ◽  
Creep Fatigue

Components of conventional power plants are subject to potential damage mechanisms such as creep, fatigue and their combination. These mechanisms have to be considered in the mechanical design process. Against this general background — as an example — the paper focusses on the low cycle fatigue behavior of a main steam shut off valve. The first design check based on standard design rules and linear Finite Element Analysis (FEA) identifies fatigue sensitive locations and potentially high fatigue usage. This will often occur in the context of flexible operational modes of combined cycle power plants which are a characteristic of the current demands of energy supply. In such a case a margin analysis constitutes a logical second step. It may comprise the identification of a more realistic description of the real operational loads and load-time histories and a refinement of the (creep-) fatigue assessment methods. This constitutes the basis of an advanced component design and assessment. In this work, nonlinear FEA is applied based on a nonlinear kinematic constitutive material model, in order to simulate the thermo-mechanical behavior of the high-Cr steel component mentioned above. The required material parameters are identified based on data of the accessible reference literature and data from an own test series. The accompanying testing campaign was successfully concluded by a series of uniaxial thermo-mechanical fatigue (TMF) tests simulating the most critical load case of the component. This detailed and hybrid approach proved to be appropriate for ensuring the required lifetime period of the component.

Fault Analysis of Solar Thermal Systems in Bhutan

2021 ◽  
pp. 60-71
Author(s):  
Tshewang Darjay ◽  
Cheku Dorji ◽  
Tshewang Lhendup ◽  
Martin Elborg
Keyword(s):  
User Behavior ◽  
Policy Instrument ◽  
Fault Analysis ◽  
Solar Thermal ◽  
Second Phase ◽  
Thermal Systems ◽  
Field Surveys ◽  
Government Sector ◽  
Solar Thermal Applications ◽  
Secondary Information

The Royal Government of Bhutan has accorded the highest priority towards diversifying the energy-mix through the promotion of renewable energy technologies. There is a national target to generate 3 MW equivalent of energy from the installation of solar thermal systems alone. However, little investment and priority are given for development of solar thermal applications. Some of the present existing solar water heating (SWH) systems are exhibiting faults which leads to low consumer confidence in SWH technology due to the non-functioning of previous installations which is very detrimental in this introductory stage. This study aims to identify problems of existing SWH systems through field surveys and develop a draft guideline to avoid faults in the future. To analyse the problems with existing SWH systems in Bhutan, the first phase of the study consists of collecting secondary information and opinion from the relevant government sector, local installing companies and end-users. The information on the manufacturer’s products, policy barriers, markets and consumer challenges is also collected. Base on this information, findings on the limitation of existing policy instrument and gap in demand and supply side is described. The second phase of the study comprises field visits to existing SWH system sites. The field surveys of twelve representative existing SWH systems are analyzed. Out of twelve sites, eight SWH systems had critical faults which causes major failure of the system and the other four sites had minor faults. To analyse the faults of existing SWH systems, faults are classified into design faults, plumbing circuit faults, solar collector faults, absorber faults, installation faults and user behavior faults. The major faults which lead to the failure of the existing SWH system are plumbing failure, condensation inside the collector and absorber tube leakage. The causes and solutions of the faults are discussed.

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