Evaluation of the Residual Service Life of a Disk of the Rotor of Steam Turbine with Regard for the Number of Shutdowns of the Equipment

2018 ◽  
Vol 53 (5) ◽  
pp. 637-644 ◽  
Author(s):  
I. Ya. Dolins’ka
Keyword(s):  
Service Life ◽  
Steam Turbine ◽  
Residual Service Life ◽  
Residual Service

Functional and operational risk as a criterion for assessing the durability of an autonomous energy system

2019 ◽  
Vol 12 (1) ◽  
pp. 56-62 ◽  
Author(s):  
A. O. Nedosekin ◽  
A. V. Smirnov ◽  
D. P. Makarenko ◽  
Z. I. Abdoulaeva
Keyword(s):  
Service Life ◽  
Structural Reliability ◽  
Residual Life ◽  
Fuzzy Random Variable ◽  
Operational Risk ◽  
Energy System ◽  
Technical System ◽  
Residual Service Life ◽  
Technological Parameters ◽  
Residual Service

The article presents new models and methods for estimating the residual service life of an autonomous energy system, using the functional operational risk criterion (FOR). The purpose of the article is to demonstrate a new method of durability evaluation using the fuzzy logic and soft computing framework. Durability in the article is understood as a complex property directly adjacent to the complex property of system resilience, as understood in the Western practice of assessing and ensuring the reliability of technical systems. Due to the lack of reliable homogeneous statistics on system equipment failures and recoveries, triangular fuzzy estimates of failure and recovery intensities are used as fuzzy functions of time based on incomplete data and expert estimates. The FOR in the model is the possibility for the system availability ratio to be below the standard level. An example of the evaluation of the FOR and the residual service life of a redundant cold supply system of a special facility is considered. The transition from the paradigm of structural reliability to the paradigm of functional reliability based on the continuous degradation of the technological parameters of an autonomous energy system is considered. In this case, the FOR can no longer be evaluated by the criterion of a sudden failure, nor is it possible to build a Markov’s chain on discrete states of the technical system. Assuming this, it is appropriate to predict the defi ning functional parameters of a technical system as fuzzy functions of a general form and to estimate the residual service life of the technical system as a fuzzy random variable. Then the FOR is estimated as the possibility for the residual life of the technical system to be below its warranty period, as determined by the supplier of the equipment.

Expected residual service life of reinforced concrete structures from current strength considerations

2019 ◽  
Vol 22 (7) ◽  
pp. 1631-1643
Author(s):  
Sushil Kumar Dhawan ◽  
Abhinav Bindal ◽  
Suresh Bhalla ◽  
Bishwajit Bhattacharjee
Keyword(s):  
Reinforced Concrete ◽  
Service Life ◽  
Residual Life ◽  
Concrete Structures ◽  
Present Condition ◽  
Material Strength ◽  
Reinforced Concrete Structures ◽  
Residual Service Life ◽  
Remaining Service Life ◽  
Residual Service

Concrete is primarily used in the form of reinforced concrete for construction of buildings, bridges and other important structures. Due to normal usage and environmental effects, the structure would gradually deteriorate. The actual residual life needs to be worked at a given time vis-à-vis the design life of the structure, commensurate with the fulfilment of essential requirements of structural integrity and safety and from strength as well as serviceability considerations. Requirements for residual life assessment would depend upon the current parameters, such as the residual cross-sectional area of concrete as well as steel, Young’s modulus of elasticity and the in situ material strength of the constituent materials, namely, concrete and steel. This article aims to develop a rigorous methodology for expected remaining service life of a reinforced concrete structure from wind/seismic considerations, based on the present condition of the structure encompassing the residual material strength and the residual reinforcement/sectional areas. The methodology development section is followed by an illustrative example and a parametric study involving a 10-storeyed reinforced concrete building frame under wind and earthquake loads. Influences of various parameters such as concrete strength and residual rebar area on the expected remaining service life are studied in detail. The proposed methodology provides a simple but rational estimation of the residual service life for reinforced concrete structures.

Reliability and residual service life of the steampipe welded joints at the temperature of 540°C

1993 ◽  
Vol 12 (2) ◽  
pp. 99-104
Author(s):  
V. Pilous ◽  
K. Stránský ◽  
P. Drybčák ◽  
P. Šlechta
Keyword(s):  
Service Life ◽  
Welded Joints ◽  
Residual Service Life ◽  
Residual Service

Influence of Corrosive Hydrogenating Media on the Residual Service Life of Structural Elements in the Maneuvering Mode of Operation

2018 ◽  
Vol 54 (1) ◽  
pp. 61-68 ◽  
Author(s):  
О. E. Andreikiv ◽  
V. R. Skal’s’kyi ◽  
І. Ya. Dolins’ka ◽  
А. R. Dzyubyk
Keyword(s):  
Service Life ◽  
Residual Service Life ◽  
Structural Elements ◽  
Mode Of Operation ◽  
Maneuvering Mode Of Operation ◽  
Residual Service
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