Health-Monitoring Methodology for High-Temperature Steam Pipes of Power Plants Using Real-Time Displacement Data

We developed a health-monitoring methodology for high-temperature steam pipes that estimated the life prediction of creep–fatigue interaction by directly measuring the displacement of hot parts. Three different methods (boiler code, design stress, and operating stress) were used to estimate the stress of the high-temperature pipe system. As a theoretical approach, the German boiler standard code calculates the stress according to the pipe shape, while design stress, which is also called allowable stress, was determined by a function of the operating temperature. The operating stress was immediately calculated using the surrogate model, with maximum displacement measured using the 3D displacement measurement system. To achieve the surrogate model, the stress was estimated by the pipe-stress analysis under the given displacements, and the surface-response model was developed to relate the stress and displacement. We showed that those methods are efficient methods to predict the stress and are applicable in health-monitoring methodology. Finally, the creep life and the low-cycle fatigue life were investigated using the Larson–Miller parameter equation, as well as the Smith, Hirschberg, and Manson equations. Our proposed monitoring system can be used to predict the fatigue and creep life of high-temperature steam pipes in real time, and we believe that the system can be applied to actual maintenance in thermal power plants.

UPM CP TITANIUM GRADE 3 (UNS R50550)

UPM CP Titanium Grade 3 (UNS R50550) is an unalloyed commercially pure titanium that exhibits moderate strength (higher strength than that of Titanium Grade 2), along with excellent formability and corrosion resistance. It offers the highest ASME allowable design stress of any commercially pure grade of titanium, and can be used in continuous service up to 425 °C (800 °F) and in intermittent service up to 540 °C (1000 °F). This datasheet provides information on composition, physical properties, and elasticity. It also includes information on corrosion resistance as well as forming, heat treating, machining, and joining. Filing Code: Ti-167. Producer or source: United Performance Metals.

Stress Testing for Credit Risk Exposure in Islamic Banks

In this study, we investigate the link between default loans and macroeconomic and bank-specific variables to assess exposure of Islamic banks to credit risks, and then design stress testing scenarios to assess the banking system’s resilience to adverse shocks. The results suggest that credit risk exposure of Islamic banks in Sudan is mainly affected by bank-specific variables, which include changes in total assets, total deposits, and total loans; all of them have a negative and significant impact on the probability of default loans. The study also indicates that the macroeconomic variables, which include growth of domestic product, change in exchange rate premium, and change in money supply, have positive but insignificant effects on the risk of default loans. The study concludes by pointing out that the Islamic banking system in Sudan is more vulnerable to bank-specific risk exposure rather than macroeconomic indicators.

Stress Multiplier for Segmented Gaskets

The use of segmented joint technology allows gasket manufacturers to fabricate and supply gaskets in discrete segments, rather than the conventional one-piece construction. Segmented gaskets are required when using sheet type gaskets for flange diameters larger than the available sheet size. Typical gasket sheets are 60” × 60” or 70” × 70” square, for instance. Flanges designed for these lower stress sheet gaskets that are larger than the available sheet size to fabricate the gaskets are typically fabricated as segmented gaskets. Segmented gaskets are also utilized in smaller flange applications to facilitate maintenance activities. When replacing the tube sheet gasket in a shell and tube exchanger the entire tube sheet must be removed in order to utilize a solid, one-piece ring gasket. In some cases this is not practical or desired, so a segmented gasket is utilized which only requires the tube sheet to be removed a short distance to allow access to the sealing surface. This same scenario exists with other common process piping and vessel flanges including thermowells, lance tubes, agitator or mixer shafts, etc. Valid concerns exist when using segmented gaskets as potential leak paths are created at every joint. If the gasket material and joint design are not correctly specified and fabricated the segmented gasket may not provide the same sealing performance and reliability as the solid, un-segmented gasket. This paper will discuss the research and data found that identifies the stress multiplier for segmented/jointed gaskets to achieve the same (similar) leak rate as their solid, unsegmented gasket counterpart. This assembly or design stress multiplier will be a dynamic number that will vary based upon the gasket material and the joining technology used. Two jointing methods are evaluated in this research; the industry standard “dovetail” and the Engineered Interference Tortuous Path (EITP) joint. In practice there is currently no guidance available to guide the design or assembly of these segmented gasket applications. The purpose of this paper is to provide guidance for both design and assembly purposes.

Specifics of determining the tension forces of the cable-stayed bridge elements

Objective: to improve the method of determining the force in the cable stays by frequencies of natural transverse oscillations. Methods: synthesis and analysis of theoretical and experimental data, experimental methods for studying the structures. Results: in the paper, the problems of determining the tension forces of the cable stays by the frequencies of their natural oscillations are considered taking into account various factors (the design of anchor fastenings, the angle of inclination and sagging of the cable stay, the change of temperature). The estimation of possible errors in calculations is given. The degree of coincidence of the actual and design stress-strain state of the cable stays depends on the correctness of accounting the influence of the factors considered. The effect of the temperature change and the anchor fastening structure on the frequency of the natural oscillations of the cable stays has been experimentally tested. The recommendations on the determination of the forces in the cable stays by dynamic parameters are given. A method for controlling the tension forces of the cable stays and specialized software “Vant” (“Cable”) for automation of the measurement process are developed. The method has been tested on several bridge structures that have cable-stayed elements. Practical significance: the ability to use the developed method for controlling the tension forces of cable-stayed elements during the operation of artificial structures.