Analytical solution for the lifetime of a spherical shell of arbitrary thickness under the pressure of corrosive environments: The effect of thermal and elastic stresses

2021 ◽  
pp. 1-25
Author(s):  
Yulia G. Pronina ◽  
Olga S. Sedova
Keyword(s):  
Corrosion Rate ◽  
Spherical Shell ◽  
Stress Component ◽  
Equivalent Stress ◽  
Circumferential Stress ◽  
Thermoelastic Stress ◽  
Decisive Role ◽  
Process Conditions ◽  
Corrosive Media ◽  
Arbitrary Thickness

Abstract The paper presents analytical solutions to initial boundary value problems of thermoelasticity with a priori unknown evolving boundaries. To be more precise, we consider a spherical shell of arbitrary thickness subjected to the internal and external pressures of corrosive media at generally different temperatures, with taking into account the mechanochemical effect and inhibition of corrosion process. Conditions under which the circumferential stress can serve as the equivalent stress are determined. It was found that the life of the shell was influenced by the competing effects of the pressures and temperatures on the corrosion rate and stress values, as well as by possible moving the location of the maximal stress. It was also concluded that the elastic stress component played a decisive role in the synergistic growth of the total thermoelastic stress and the corrosion rate.

Steady-State Thermal Stresses in Wedge-Shaped Cutting Tools

1975 ◽  
Vol 97 (3) ◽  
pp. 1060-1066
Author(s):  
P. F. Thomason
Keyword(s):  
Thermal Stress ◽  
Steady State ◽  
Metal Cutting ◽  
Thermal Stresses ◽  
Heat Conduction Problem ◽  
Equivalent Stress ◽  
Cutting Tools ◽  
Thermoelastic Stress ◽  
Plastic State ◽  
Steady State Heat

Closed form expressions for the steady-state thermal stresses in a π/2 wedge, subject to constant-temperature heat sources on the rake and flank contact segments, are obtained from a conformal mapping solution to the steady-state heat conduction problem. It is shown, following a theorem of Muskhelishvili, that the only nonzero thermal stress in the plane-strain wedge is that acting normal to the wedge plane. The thermal stress solutions are superimposed on a previously published isothermal cutting-load solution, to give the complete thermoelastic stress distribution at the wedge surfaces. The thermoelastic stresses are then used to determine the distribution of the equivalent stress, and this gives an indication of the regions on a cutting tool which are likely to be in the plastic state. The results are discussed in relation to the problems of flank wear and rakeface crater wear in metal cutting tools.

scholarly journals Wear and Corrosion of Wrought A6061 Aluminium Alloy in DOT3 Brake Fluid

2018 ◽  
Vol 7 (2.14) ◽  
pp. 512 ◽  
Author(s):  
Olawale Ajibola ◽  
Oladeji Ige ◽  
Peter Olubambi
Keyword(s):  
Corrosion Rate ◽  
Test Method ◽  
Alloy Sample ◽  
Corrosive Media ◽  
Chemical Corrosion ◽  
Brake Fluid ◽  
Wear And Corrosion ◽  
Cast Specimen ◽  
Fluid Environment ◽  
A6061 Alloy

The twofold impact of wear and corrosion on wrought A6061 alloy in hydraulic DOT3 brake fluid environment was studied. The wear studies were performed on the samples using a developed wear-jig. Weight loss corrosion test method was used to determine the corrosion rate of the wrought A6061 alloy samples immersed in the brake fluid for a total of 1680 hours. From the results of wear tests carried out on the A6061 alloy sample with brake oil, the highest wear value of 5.24x10-7 mg/mm2/cycle (approx.) was obtained from 6 N (approx) force after 130 minutes. The wrought A6061 alloy material demonstrated the highest corrosion rates nearly 3.0 x10-2 mg/mm2/yr within the early 168 hours of immersion in brake fluid. The result is practically lower than the corrosion rate of cast specimen in DOT3 brake oil or some other alloys immersed in other corrosive media that were previously reported in the literature. The results show that small amount of chemical corrosion is sufficient to cause and accelerate mechanical wear of the material in usage.

Corrosion of pipe steels 20 and 17G1S-U in ground electrolytes with a hydrogen indicator close to neutral

2021 ◽  
Vol 1 (108) ◽  
pp. 16-23
Author(s):  
M. Polutrenko ◽  
P. Maruschak ◽  
A. Babii ◽  
O. Prentkovskis
Keyword(s):  
Corrosion Rate ◽  
Protective Effect ◽  
Residual Life ◽  
Aggressive Medium ◽  
Borate Buffer ◽  
Soil Conditions ◽  
Process Conditions ◽  
Pipe Steels ◽  
Gas Pipelines ◽  
Protective Properties

Purpose: of this paper is to analyse the mechanism of near-neutral pH corrosion of main gas pipelines. The stages of main gas pipelines in model environments that meet the soil conditions of Ukraine have been studied. Design/methodology/approach: The corrosion rate of steel specimens from steels 17G1S-U and 20 and the influence of borate buffers on their protective properties were evaluated. The influence of corrosion time on changes in pH of model media is shown. Morphological features of surface damages of pipe steels are established. The defect analysis of specimens from steels 17G1S-U and 20 by electron scanning microscopy is carried out. Findings: The effect of borate buffers on the protective properties of the steel grades studied was revealed, and changes in the pH of the model media during corrosion processes were described. The main regularities in corrosion, as well as the surface morphology of damaged specimens, were studied by scanning electron microscopy. Research limitations/implications: Detailed investigation of localised corrosion phenomena induced by inclusions that are present in steels 17G1S-U and 20 is extremely critical. In particular, there is still ambiguity as to whether the localised corrosion initiation induced by non-metallic inclusions is an electrochemical process or a chemical process. Practical implications: The research findings will be used when testing specimens from pipe steels under cyclic loading in the model media studied, as well as for predicting the residual life of gas pipelines with corrosion defects. Their generalization will make it possible to develop the effective methods of ground diagnostics and prediction of SCC of main pipelines. Originality/value: It was found that the corrosion rate is determined by internal (nature and properties of the metal) and external (properties of the aggressive medium and the corrosion process conditions) factors. The protective effect for steel 17G1S in medium NS4 + borate buffer (1: 1) was 61.5%. Steel 20 had the greatest protective effect in medium NS4 + borate buffer (1: 3), which was 87.05%.

Axisymmetric Thermal Stresses in a Spherical Shell of Arbitrary Thickness

1957 ◽  
Vol 24 (3) ◽  
pp. 376-380
Author(s):  
E. L. McDowell ◽  
E. Sternberg
Keyword(s):  
Steady State ◽  
Spherical Shell ◽  
Spherical Cavity ◽  
Series Solution ◽  
Thermal Stresses ◽  
Solid Sphere ◽  
Theory Of Elasticity ◽  
Infinite Medium ◽  
Series Solutions ◽  
Arbitrary Thickness

Abstract This paper contains an explicit series solution, exact within the classical theory of elasticity, for the steady-state thermal stresses and displacements induced in a spherical shell by an arbitrary axisymmetric distribution of surface temperatures. The corresponding solutions for a solid sphere and for a spherical cavity in an infinite medium are obtained as limiting cases. The convergence of the series solutions obtained is discussed. Numerical results are presented appropriate to a solid sphere if two hemispherical caps of its boundary are maintained at distinct uniform temperatures.

scholarly journals Influence of Heat Treatment on the Corrosion Behaviour of Aluminium Silver Nano Particle/Calcium Carbonate Composite

2021 ◽  
Vol 5 (10) ◽  
pp. 280
Author(s):  
Omolayo Michael Ikumapayi ◽  
Esther T. Akinlabi ◽  
Olayinka Oluwatosin Abegunde ◽  
Precious Ken-Ezihuo ◽  
Henry A. Benjamin ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Corrosion Rate ◽  
Corrosion Behaviour ◽  
Stir Casting ◽  
Corrosion Properties ◽  
Corrosive Media ◽  
Loss Analysis ◽  
Weight Composition ◽  
Analysis Technique ◽  
Hybrid Reinforcement

Corrosion is one of the leading sources of material failure and deterioration in society. Scholars have proposed different techniques to mitigate corrosion. This research study explores and validates one of these techniques. An Aluminium metal matrix (AMC) was produced using the stir casting method with various weight percentages of AgNp and CaCO3 reinforcements. Heat treatment was performed on the samples to enhance the metallurgical and corrosion properties of the materials. The corrosion rate of the AMC samples was tested in different corrosive media (neutral and acidic) with different concentrations using the weight loss analysis technique for several days. It was observed that the corrosion rate of the AMC relies on the nature of the electrolyte and the percentage concentration of this electrolyte. The heat treatment improves the corrosion resistance of the AMC samples. In addition, an increase in the % weight composition of the reinforcement (AgNp + CaCO3) results in a reduction in the corrosion rate of the AMC in both corrosive media. The optimal %weight composition was found to be 4% for the hybrid reinforcement of AgNp + CaCO3 and 6% for the CaCO3 reinforcement in both the untreated and heat-treated samples.

Residual Stress and Circumferential Stress Distribution in a Finite Element Model of the Arterial Wall

Volume 2 ◽  
2004 ◽  
Author(s):  
Nooshin Haghighipour ◽  
Mohammad Tafazzoli Shadpour ◽  
Albert Avolio
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Stress Distribution ◽  
Tensile Stress ◽  
Arterial Wall ◽  
Stress Component ◽  
Circumferential Stress ◽  
Opening Angle ◽  
Human Aorta ◽  
Endothelial Lining

Stress distribution of the arterial wall is an important factor in biomechanics of arteries. It has been suggested that excessive stress leads to arterial degeneration and lesion formation. In addition to circumferential tensile stress caused by luminal pressure, arterial wall contains circumferential residual stress with compressive and tensile components with maximum values on intima and adventitia respectively. The compressive residual stress component compensates part of maximum tensile stress, and therefore decreases severity of tension on endothelial lining. If an arterial ring is cut in radial direction it opens. The degree of opening angle is a determinant of circumferential residual stress. In this investigation, Finite element modeling was used to evaluate circumferential residual stress in a typical model of cross section of human aorta with differing opening angle and Young’s modulus of elasticity. Results show that residual stress values are influenced by structural and mechanical parameters. Elevation of the opening angle and stiffening of the arterial wall resulted in increase of residual stress level.

Dual BEM Formulation Applied to Analysis of Multiple Crack Propagation

2013 ◽  
Vol 560 ◽  
pp. 99-106 ◽  
Author(s):  
H.L. Oliveira ◽  
Edson Denner Leonel
Keyword(s):  
Stress Intensity ◽  
Crack Propagation ◽  
Equivalent Stress ◽  
Circumferential Stress ◽  
Singular Integral Equations ◽  
Correlation Technique ◽  
Multiple Crack ◽  
Proposed Model ◽  
Length Increment ◽  
Crack Growth Path

The boundary element method (BEM) is used in this paper for modelling multiple crack propagation in two-dimensional domains. The formulation adopted is based on the dual BEM, in which singular and hyper-singular integral equations are used. An iterative scheme is proposed in order to predict the crack growth path and the crack length increment at each load step. This scheme is accurate enough to simulate localisation and coalescence phenomena, which is the main contribution of this paper. The displacement correlation technique is used to evaluate the stress intensity factors and the theory of maximum circumferential stress is adopted to determine the crack propagation angle and the equivalent stress intensity factor. One application is presented in order to illustrate the robustness and applicability of the proposed model.

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