Paper 5: Design Aspects of Large Marine Engines

1966 ◽  
Vol 181 (8) ◽  
pp. 10-19
Author(s):  
J. F. Butler ◽  
F. Ørbeck
Keyword(s):  
Thermal Loading ◽  
Bending Moments ◽  
Bending Stress ◽  
Slow Speed ◽  
Piston Head ◽  
Marine Engines ◽  
Concentration Factors ◽  
Stress Concentration Factors ◽  
Frame Stiffness

The paper deals with large slow-speed marine engines with a section on crankshaft stresses, including dynamic torque calculation; static bending moments owing to firing pressure, inertia, and misalignment; combined torque and bending stress; and experimental determination of stress concentration factors in the fillet radii. Other sections deal with top end bearing loading including cyclic variation, piston head stresses, deflection of bearing housings, prestressing of main bolts, frame stiffness, and stress in combustion chamber studs as a result of pressure and thermal loading.

Analysis of Stress Concentrations in Thick Cylinders With Sideholes and Crossholes

1972 ◽  
Vol 94 (3) ◽  
pp. 815-824 ◽  
Author(s):  
J. C. Gerdeen
Keyword(s):  
Stress Concentration ◽  
Stress Concentrations ◽  
Concentration Factors ◽  
Stress Concentration Factors ◽  
Experimental Values ◽  
Pressure Stress ◽  
Shrink Fit ◽  
Outside Diameter ◽  
Theoretical Results

An approximate theoretical analysis is presented for the determination of stress concentration factors in thick walled cylinders with sideholes and crossholes. The cylinders are subjected to both internal pressure and external shrink-fit pressure. Stress concentration factors are plotted as functions of the geometrical ratios of outside diameter-to-bore diameter, and bore diameter-to-sidehole diameter. Theoretical results are compared to experimental values available in the literature and results of experiments described in a separate paper.

Computer Aided Analysis of Bending Strength of Involute Spur Gears with Asymmetric Profile

2004 ◽  
Vol 127 (3) ◽  
pp. 477-484 ◽  
Author(s):  
Kadir Cavdar ◽  
Fatih Karpat ◽  
Fatih C. Babalik
Keyword(s):  
Computer Program ◽  
Bending Strength ◽  
Spur Gears ◽  
Bending Stress ◽  
Contact Ratio ◽  
Computer Aided Analysis ◽  
Tooth Form ◽  
Stress Concentration Factors ◽  
Stress Minimization

This paper presents a method for the determination of bending stress minimization of involute spur gears. A computer program has been developed to investigate the variation of bending stress and contact ratio depending on the pressure angle on the drive side. Since asymmetric tooth is not standard, the tooth model, which was introduced by DIN 3990/Method C and ISO/TC 60, has been adjusted for asymmetric tooth by the authors. The determination of the tooth form and stress concentration factors for asymmetric tooth has been accomplished for each different parameter (pressure angles, tool radius, rack shift, etc.). The sample results, which were obtained by using a developed computer program, are illustrated with numerical examples.

Stress-Concentration Factors in Shafts With Transverse Holes as Found by the Electroplating Method

1955 ◽  
Vol 22 (2) ◽  
pp. 193-196
Author(s):  
H. Ōkubo ◽  
S. Satō
Keyword(s):  
Stress Concentration ◽  
Outer Surface ◽  
Maximum Stress ◽  
Accurate Determination ◽  
Slicing Method ◽  
Concentration Factors ◽  
Mathematical Difficulties ◽  
Stress Concentration Factors ◽  
Maximum Stresses

Abstract In this paper the torsion of shafts with transverse holes has been investigated experimentally. Usual methods for stress measurements, such as the method of brittle coatings and the use of sensitive extensometers, are not applied effectively to the present problem because the maximum stress occurs in the bore and does not occur on the outer surface of the shaft. The stress may be measured by the stress-freezing and slicing method but we cannot expect too much from this method for the accurate determination of the stress when the diameter of the hole is comparatively small. In treating the problem theoretically, considerable mathematical difficulties are encountered on account of its axially nonsymmetrical nature. The electroplating method recently developed by one of the authors (1), however, has been proved to be useful in this case, so the maximum stresses in shafts are measured by this method and the stress-concentration factors are found for various diameters of the hole.

A Multidimensional FEA Approach for Determination of Hot Spot Stresses in Offshore Jacket Structures

2021 ◽  
Author(s):  
Kris Hectors ◽  
Hasan Saeed ◽  
Wim De Waele
Keyword(s):  
Fatigue Life ◽  
Stress Concentration ◽  
Hot Spot ◽  
Wave Spectrum ◽  
Wave Direction ◽  
Tubular Joints ◽  
Jacket Structures ◽  
Concentration Factors ◽  
Stress Concentration Factors

Abstract A new fatigue lifetime assessment approach for offshore jacket structures is presented. It combines a previously developed numerical framework for automated determination of stress concentration factors in tubular joints and a multidimensional finite element modelling approach. The approach is explained based on a case study of an OC4 type offshore jacket. To determine the fatigue life, a directional wave spectrum is combined with the JONSWAP spectrum. The fatigue life of the jacket is assessed for two different sea states. Based on the fatigue analysis the most fatigue critical wave direction is identified. The hot spot stresses in one of the most critical joints are determined and compared to stresses obtained with the Efthymiou equations. The shortcomings of these equations are highlighted and it is shown how the numerical framework can be used to improve the current fatigue design philosophy for offshore jackets which relies on the Efthymiou equations for stress concentration factors in the welded tubular joints.

Determination of the Eextreme Stress in the High-Pressure Drum Power Boilers

10.12737/7782 ◽  
2014 ◽  
Vol 2 (2) ◽  
pp. 83-90
Author(s):  
Михаил Сербиновский ◽  
Mikhail Serbinovskiy ◽  
Максим Курепин ◽  
Maksim Kurepin
Keyword(s):  
High Pressure ◽  
Low Cycle Fatigue ◽  
Steam Boiler ◽  
Extreme Stress ◽  
Stress Changes ◽  
Local Stresses ◽  
Concentration Factors ◽  
Stress Concentration Factors ◽  
Welded Pipe

The simulation results of the stress-strain state using the software ANSYS area pipe connection to the steam boiler high pressure drum for pipe connections of various diameters and wall thickness. The areas of extreme local stresses and values of strains caused by the pressure inside the drum and the pipe connection and the temperature gradient in their walls have been determined, stress concentration factors have been calculated. A comparison of the calculated stresses with the stresses obtained by the strain measurement of a physical model of the drum with welded pipe connections has been made. Functions of the extreme stress changes depending on the position of the diametrical section of the pipe connection has been determined. Using the obtained values of stress and concentration coefficients allow to specify the strength calculation of the high-pressure drum and their reliance on low-cycle fatigue

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