scholarly journals Assessment of the Durability of Threaded Joints

2021 ◽  
Vol 11 (24) ◽  
pp. 12162
Author(s):  
Žilvinas Bazaras ◽  
Mindaugas Leonavičius ◽  
Vaidas Lukoševičius ◽  
Laurencas Raslavičius
Keyword(s):  
Shape Change ◽  
Failure Process ◽  
Experimental Studies ◽  
Pressure Vessels ◽  
Experimental Investigations ◽  
Engineering Practice ◽  
Calculation Methods ◽  
Limit States ◽  
Plastic Failure ◽  
Threaded Joints

The article deals with the determination of the resistance to cyclic loading of the threaded joints of pressure vessels and defective elements according to the failure mechanics criteria. Theoretical and experimental studies do not provide a sufficient basis for the existing calculation methods for the cyclic strength of the threaded joints of pressure vessels. The short crack kinetics in the threaded joints, a shakedown in one of the joint elements of pressure vessels, i.e., in the bolt or stud, has not been studied sufficiently. The calculation methods designed and improved within the study were based on theoretical and experimental investigations and were simplified for convenient application to engineering practice. The findings could be used to investigate the shakedown of studs of a different cross-section with an initiating and propagating crack. Value: the developed model for the assessment of durability of the threaded joints covers the patterns of resistance to cyclic failure (limit states: crack initiation, propagation, final failure) and shakedown (limit states: progressive shape change and plastic failure). Analysis-based solutions of plastic failure conditions and progressive shape change were accurate (the result was reached using a two-sided approach; the solutions were obtained in view of the parameters of the cyclic failure process in the stud (bolt) and based on experimental investigations of the threaded joints).

Numerical and Experimental Analysis of Stress and Strains in Flat Ends of High-Pressure Vessels

2011 ◽  
Vol 490 ◽  
pp. 226-236 ◽  
Author(s):  
Bogdan Szybiński ◽  
Paweł Romanowicz ◽  
Andrzej P. Zieliński
Keyword(s):  
High Pressure ◽  
Numerical Study ◽  
Stress Relief ◽  
Pressure Vessels ◽  
Experimental Investigations ◽  
Engineering Practice ◽  
Junction Area ◽  
Definite Answer ◽  
Asme Code ◽  
Relief Groove

Application of flat welded ends with stress relief grooves in high-pressure vessels is a common alternative to use of dished vessel ends. It is well established and follows calculation rules given in codes: EN-12952-3 [1], EN-13445-3 [2], or in ASME code [3]. However the calculation rules do not give any definite answer what should be the choice of parameters defining a circular stress relief groove, for example, position of the groove and its radius. Usually the choice of them relies on engineering practice. The present paper clearly shows the influence of this choice on stress concentration in the cylinder-endplate junction area. The results of numerical study are verified in experimental investigations performed for a cylindrical high-pressure vessel.

scholarly journals PECULIARITIES OF CALCULATING THE CYCLIC STRENGTH OF IMPORTANT THREADED JOINTS

2002 ◽  
Vol 8 (1) ◽  
pp. 42-48
Author(s):  
Mindaugas Leonavičius ◽  
Algimantas Krenevičius ◽  
Stanislav Stupak ◽  
Marijonas Šukšta
Keyword(s):  
Nuclear Power ◽  
Cyclic Strength ◽  
Minimum Size ◽  
Power Equipment ◽  
Calculation Methods ◽  
Limit States ◽  
Theoretical Investigations ◽  
Asme Code ◽  
Threaded Joints ◽  
Definition Of

The calculation of the strength of important threaded joints is started by defining the minimum size of the cross-section of bolts (studs). Then the static and cyclic strength is tested. The studs of the demountable joints of nuclear power equipment are calculated in accordance with the norms of the Russian Federation and the ASME Code. The calculation methods coincide in essence, they are based on similar limit states; however, there also some differences exist. The authors investigate and compare both methods in their work. There is a brief analysis of calculation methods in the article. For closer definition of standards and their substantiation the authors used experimental and theoretical investigations performed at Laboratory of Strength Mechanics of Vilnius Gediminas Technical University. In order to develop a uniform cyclic strength and shakedown calculation procedure for critical threaded joints, a completely new calculation of a progressive profile change is recommended to be performed before the calculation of cyclic strength. The results have been used in the development of calculation standards for nuclear power equipment, in designing mineral grinding machines and evaluating their residual resource.

Computational and experimental studies of the strength of full-scale samples of pipes with defects "metal loss" and "dent with groove"

2020 ◽  
Vol 10 (3) ◽  
pp. 226-233
Author(s):  
Dmitry A. Neganov ◽  
◽  
Victor M. Varshitsky ◽  
Andrey A. Belkin ◽  
◽  
...  
Keyword(s):  
Internal Pressure ◽  
Experimental Studies ◽  
Full Scale ◽  
The Other ◽  
Metal Loss ◽  
Calculation Methods ◽  
Reliable Operation ◽  
Sufficient Stability ◽  
Comparative Results ◽  
The Moment

The article contains the comparative results of the experimental and calculated research of the strength of a pipeline with such defects as “metal loss” and “dent with groove”. Two coils with diameter of 820 mm and the thickness of 9 mm of 19G steel were used for full-scale pipe sample production. One of the coils was intentionally damaged by machining, which resulted in “metal loss” defect, the other one was dented (by press machine) and got groove mark (by chisel). The testing of pipe samples was performed by applying static internal pressure to the moment of collapse. The calculation of deterioration pressure was carried out with the use of national and foreign methodical approaches. The calculated values of collapsing pressure for the pipe with loss of metal mainly coincided with the calculation experiment results based on Russian method and ASME B31G. In case of pipe with dent and groove the calculated value of collapsing pressure demonstrated greater coincidence with Russian method and to a lesser extent with API 579/ASME FFS-1. In whole, all calculation methods demonstrate sufficient stability of results, which provides reliable operation of pipelines with defects.

scholarly journals Roll Bonding of Al-Based Composite Reinforced with C10 Steel Expanded Mesh Inlay

Metals ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1044
Author(s):  
Yaroslav Frolov ◽  
Maxim Nosko ◽  
Andrii Samsonenko ◽  
Oleksandr Bobukh ◽  
Oleg Remez
Keyword(s):  
Impact Energy ◽  
High Efficiency ◽  
Shape Change ◽  
Experimental Investigations ◽  
Aluminum Composite ◽  
Rolling Mills ◽  
Roll Bonding ◽  
Finite Element Software ◽  
Steel Mesh ◽  
Bonded Composite

The most complex issue related to the design of high efficiency composite materials is the behavior of the reinforcing component during the bonding process. This study presents numerical and experimental investigations of the shape change in the reinforcing inlay in an aluminum-steel mesh-aluminum composite during roll-bonding. A flat composite material consisting of two outer strips of an EN AW 1050 alloy and an inlay of expanded C10 steel mesh was obtained via hot roll bonding with nominal rolling reductions of 20%, 30%, 40% and 50% at a temperature of 500 °C. The experimental procedure was carried out using two separate rolling mills with diameters equal to 135 and 200 mm, respectively. A computer simulation of the roll bonding was performed using the finite element software QForm 9.0.10 by Micas Simulations Limited, Oxford, UK. The distortion of the mesh evaluated via the change in angle between its strands was described using computer tomography scanning. The dependence of the absorbed impact energy of the roll bonded composite on the parameters of the deformation zone was found. The results of the numerical simulation of the steel mesh shape change during roll bonding concur with the data from micro-CT scans of the composites. The diameter of rolls applied during the roll bonding, along with rolling reduction and temperature, have an influence on the resulting mechanical properties, i.e., the absorbed bending energy. Generally, the composites with reinforcement exhibit up to 20% higher impact energy in comparison with the non-reinforced composites.

scholarly journals Experimental Evaluation of Airlift Performance for Vertical Pumping of Water in Underground Mines

2021 ◽  
Author(s):  
Parviz Enany ◽  
Oleksandr Shevchenko ◽  
Carsten Drebenstedt
Keyword(s):  
Water Flow ◽  
High Efficiency ◽  
Experimental Studies ◽  
Theoretical Models ◽  
Injection System ◽  
Experimental Investigations ◽  
Flow Mode ◽  
New Device ◽  
Riser Pipe ◽  
Airlift Pump

AbstractThis paper presents experimental studies on the optimization of air–water flow in an airlift pump. Airlift pumps use compressed gas to verticall transport liquids and slurries. Due to the lack of theoretical equations for designing and predicting flow regimes, experimental investigations must be carried out to find the best condition to operate an airlift pump at high efficiency. We used a new air injection system and different submergence ratios to evaluate the output of a simple pump for vertical displacement of water in an underground mine. The tests were carried out in a new device with 5.64 m height and 10.2 cm circular riser pipe. Three air-jacket pipes, at different gas flows in the range of 0.002–0.09 m3/s were investigated with eight submergence ratios. It was found that with the same air flow rate, the most efficient flow of water was achieved when an air jacket with 3 mm diameter holes was used with a submergence ratio between 0.6 and 0.75. In addition, a comparison of practical results with two theoretical models proposed by other investigators showed that neither was able to accurately predict airlift performance in air–water flow mode.

Numerical and experimental studies on the thermal and static characteristics of multi-leaf foil thrust bearing

2021 ◽  
pp. 135065012110110
Author(s):  
Yu Guo ◽  
Yu Hou ◽  
Qi Zhao ◽  
Xionghao Ren ◽  
Shuangtao Chen ◽  
...  
Keyword(s):  
High Speed ◽  
Thrust Bearing ◽  
Load Capacity ◽  
Failure Process ◽  
Experimental Studies ◽  
Elastic Model ◽  
Static Characteristics ◽  
Bearing Load ◽  
Foil Thrust Bearing ◽  
Cooling Air

Foil bearing is considered to be a promising supporting technology in high-speed centrifugal machinery. Due to the high-speed shearing effect in the viscous lubricant film, heat generation could not be ignored. In this paper, a thermo-elastic model of the multi-leaf foil thrust bearing is proposed to predict its thermal and static characteristics. In the model, modified Reynolds equation, energy equation, and Kirchhoff equation are solved in a coupling way. The contact area between the foil and welding plate is taken into account. Besides, the effect of cooling air on the bearing temperature is investigated. The ultimate load capacity and transient overload failure process of the bearing is analyzed and discussed. The effect of rotation speed on the bearing temperature is more obvious than that of the bearing load. The bearing temperature drops obviously by introducing the cooling air, and the cooling effect is improved with the supply pressure. The transient overload failure of the bearing occurs when the bearing load exceeds the ultimate value.

scholarly journals ДОСЛІДЖЕННЯ ГІГІЄНІЧНИХ ВЛАСТИВОСТЕЙ МАТЕРІАЛІВ НАТІЛЬНОЇ ЛІКАРНЯНОЇ БІЛИЗНИ

2020 ◽  
Vol 140 (6) ◽  
pp. 38-47
Author(s):  
І. О. Іванов ◽  
Н. П. Супрун ◽  
Ю. О. Ващенко
Keyword(s):  
Comparative Analysis ◽  
Materials Science ◽  
Experimental Studies ◽  
Operating Conditions ◽  
Raw Material ◽  
Experimental Investigations ◽  
Textile Materials ◽  
Composition And Structure ◽  
Innovative Materials ◽  
Basic Functions

Investigation of the influence of the peculiarities of raw material composition and structure of traditional and innovative linen textile materials on their hygienic properties. Theoretical and experimental investigations are based on the main positions of textile materials science. In experimental studies, modern standardized methods for determining the hygienic properties of textile materials were used, as well as techniques specially developed taking into account the peculiarities of the operating conditions of underwear. The peculiarities of the operating conditions and the basic functions of hospital underwear were determined. The comparative analysis of hygienic properties of traditional and modern fabrics for underwear was carried out. Using the standardized and the developed methods, adapted to the peculiarities of the conditions of use of the products, the indicators characterizing the processes of water absorption of the materials were experimentally determined. On the basis of the obtained values of quality indicators, a comprehensive assessment of the ability of materials to transfer moisture and air, with the calculation of the arithmetic complex quality index was done. This allowed to determine the material that is optimal in properties, which provides thermophysiological comfort when operating hospital underwear. Using the developed methods, which take into account the specifics of the operating conditions, a comparative analysis of the hygienic properties of traditional and innovative materials for underwear was carried out. A new range of textile materials for underwear has been proposed, taking into account the peculiarities of the operational situation of consumption.

scholarly journals Aerodynamics and Heat Transfer Investigations on a High Reynolds Number Turbine Cascade

1991 ◽  
Author(s):  
Taher Schobeiri ◽  
Eric McFarland ◽  
Frederick Yeh
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
High Reynolds Number ◽  
Test Facility ◽  
Experimental Investigations ◽  
Turbine Cascade ◽  
Calculation Methods ◽  
Transfer Coefficients ◽  
Pressure Distributions ◽  
High Reynolds

In this report the results of aerodynamic and heat transfer experimental investigations performed in a high Reynolds number turbine cascade test facility are analyzed. The experimental facility simulates the high Reynolds number flow conditions similar to those encountered in the space shuttle main engine. In order to determine the influence of Reynolds number on aerodynamic and thermal behavior of the blades, heat transfer coefficients were measured at various Reynolds numbers using liquid crystal temperature measurement technique. Potential flow calculation methods were used to predict the cascade pressure distributions. Boundary layer and heat transfer calculation methods were used with these pressure distributions to verify the experimental results.

scholarly journals Design and Experimental Investigations on NOx Emission Control Using FOCDM (Fractional-Order-Based Coefficient Diagram Method)-PIλDµ Controller

2020 ◽  
Vol 53 (5) ◽  
pp. 695-703
Author(s):  
Maheswari Chennippan ◽  
Priyanka E. Bhaskaran ◽  
Thangavel Subramaniam ◽  
Balasubramaniam Meenakshipriya ◽  
Kasilingam Krishnamurthy ◽  
...  
Keyword(s):  
Fractional Order ◽  
Packed Column ◽  
Experimental Studies ◽  
Pso Algorithm ◽  
Experimental Investigations ◽  
Nox Removal ◽  
Diagram Method ◽  
Coefficient Diagram Method ◽  
Fractional Order Controller ◽  
G Ratio

This paper aims to explore experimental studies on the NOx removal process by using pilot plant packed column experimental hardware. Physical modeling based on chemical absorption equations is used to estimate the diameter concerning the height and L/G ratio. Hydrogen peroxide is used as the additive for achieving high NOx removal efficiency. The absorbent entering into the packed column has been controlled by varying its flow rate through the fractional order controller. The FOCDM-PIλDµ controller tuning parameters such as KP, τI, τD are determined using CDM (Coefficient Diagram Method) PID control strategy and the additional parameters of FOCDM-PIλDµ controller such as λ and µ are determined based on the PSO algorithm. The comparative analysis is performed with classical controllers like ZN-PID along with the CDM-PID controllers.

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