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Finite element analysis (FEA) has been carried out utilizing the ANSYS software package to assess the failure of thick and thin‐walled steel cylindrical pressure vessels. A simple experimental stress analysis (ESA) procedure is described to evaluate the stress components on inner and outer surfaces of the vessels under internal pressure from the measured surface strains. The procedure is validated considering the strain values of FEA for the applied pressure as measured quantities and obtained the corresponding stress components considering the stress‐strain data of the material from ESA and compared with those of FEA results. Failure pressure estimates from FEA (based on the global plastic deformation) were found to be in good agreement with test results of thin as well as thick‐walled cylindrical vessels made of ductile steel materials.

IN a previous paper (AIRCRAFT ENGINEERING, Vol. XIX, February 1947, pp. 52–4) expressions were derived for the maximum bending moment and shearing force in vessels closed at one end and subjected internally to (a) gas pressure, (b) hydrostatic pressure. The method of solution has been extended in this paper to include the cases of cylindrical vessels, closed at both ends by flat plates or hemispherical shells and subjected to gas pressure.

The objective of the research work is to predict the volume of fluid drained from a cylindrical vessel without entrapping air through the drainpipe, and hence predict the location of the free surface of the liquid in the vessel.

A two‐dimensional axi‐symmetric numerical simulation has been made using a finite volume method that employs unstructured grids with cell‐wise local refinement and an interface capturing scheme to predict the shape of the free surface of water in a cylindrical vessel, thus simulating the entrapment of air in the drainpipe connected to the vessel.

A drain cover was placed on top of the drainpipe to delay the entry of air into the drainpipe. It was found that an increase in the diameter of the drain cover increases the amount of liquid to be drained out before the air could enter into the drainpipe. It was found that air enters the drainpipe at a particular height of the liquid in the vessel. However, when an initial rotational velocity was imparted to the liquid, the height of liquid when air enters the drainpipe depends on the initial bath height. As the initial bath height increases, air enters the drainpipe at a progressively higher bath height. But surprisingly when the drain cover is put in place the initial bath height, again, has no effect on the height of the liquid (in the vessel).

The outcome of the present research work has direct implications for steel making. If the drainpipe can be connected to the ladle the way it has been discussed in this paper then more steel can be drained before stopping the drainage in order to avoid air or slag entrapment.

The idea of putting a drain cover, using a larger diameter drainpipe and making the drainpipe connection to the vessel different so as to delay the appearance of air at the drainpipe is a new finding and the idea can be used by steel makers.

Filament wound pressure vessels have a characteristic pattern observed in their helical layers. These are mosaic‐shaped patterns and affect the layer structural behavior. The present research aims to focus on the influence of mosaic patterns on stress‐strain field and structural design of thin‐walled internally pressurized filament wound pressure vessel. The widely used stress analysis procedures and the commercially available finite element tools usually neglect the effect of the mosaic patterns. The present work seeks to deal with the modeling and stress analysis of complete pressure vessel, incorporating mosaic patterns.

The incorporation of the mosaic effect provides more realistic modeling of the real stress distribution and the stress values compared to the conventional analyses (the effect would depend on the shell structure, i.e. number of plies, relative thicknesses, etc.). The structural analysis is performed using commercial finite element analysis (FEA) tools ANSYS.

The comparison of results of analytical solution and conventional FEA provides close values of the stresses in the plies. As for the stress and strain distributions obtained by incorporating the effect of mosaic patterns are considerably different. The distribution of the stress and strain fields are not uniform along the length of the vessel and along its circumference and the maximum stresses acting in the direction of the fibers are higher than those calculated using conventional FEA techniques.

Previous work was limited to composite cylindrical shells, without incorporating the end domes. The present work deals with the modeling and stress analysis of complete pressure vessel, incorporating mosaic patterns.

The numerical simulation of two‐dimensional incompressible complex flows of viscoelastic fluids is presented. The context is one, relevant to the food industry (dough kneading), of stirring within a cylindrical vessel, where stirrers are attached to the lid of the vessel. The motion is driven by the rotation of the outer vessel wall, with various stirrer locations. With a single stirrer, both a concentric and an eccentric configuration are considered. A double‐stirrer eccentric case, with two symmetrically arranged stirrers, is also contrasted against the above. A parallel numerical method is adopted, based on a finite element semi‐implicit time‐stepping Taylor‐Galerkin/pressure‐correction scheme. For viscoelastic fluids, constant viscosity Oldroyd‐B and two shear‐thinning Phan‐Thien/Tanner constitutive models are employed. Both linear and exponential models at two different material parameters are considered. This permits a comparison of various stress, shear and extensional properties and their respective influences upon the flow fields generated. Variation with increasing speed of vessel and change in mixer geometry are analysed with respect to the flow kinematics and stress fields produced. Optimal kneading scenarios are commended with asymmetrical stirrer positioning, one‐stirrer proving better than two. Then, models with enhanced strain‐hardening, amplify levels of localised maxima in rate‐of‐work done per unit power consumed. Simulations are conducted via distributed parallel processing, performed on work‐station clusters, employing a conventional message passing protocol (PVM). Parallel results are compared against those obtained on a single processor (sequential computation). Ideal linear speed‐up with the number of processors has been observed.

Pressure vessel is a closed cylindrical vessel for storing gaseous, liquids or solid products. The stored medium is at a particular pressure and temperature. The cylindrical vessel is closed at both ends by means of dished head, which may be hemispherical, ellipsoidal. The pressure vessels may be horizontal or vertical. The supporting system of this vertical vessel plays an important role in the performance of the equipment. Proper supporting system gives better efficiency. The bottom supports are critical components since they are to be designed with much care to avoid failure due to internal pressure with temperature. In this analysis, skirt support for vertical vessel was analyzed as per the guidelines given in the ASME (American Society of Mechanical Engineering) section VIII division 2 and IBR (Indian Boiler Regulations) standards. The stress analysis was carried out for this support using a general purpose FEM code, ANSYS macros. The coupled field (Structural and Thermal) Analysis was carried out for skirt support to find out the stresses in the support. The analysis’s results were compared with ASME code allowable stress values.

Integrity assessment is used to ensure reliability operation of a pressurized equipment containing defects. Based on data of cylindrical shell dimensions, operation conditions, material properties and crack dimensions, an assessment can be carried out, using either Level 1, Level 2 or Level 3 procedure. Assessment using Level 3 procedure within the code requires a finite element simulation in order to generate both the evaluation point and the failure assessment diagram (FAD) that serves as the acceptance criteria. The purpose of this paper is to provide the numerical data which are used for integrity assessment of a pressure vessel containing crack. Here, a parametric study has been carried out to generate such result for the cases of longitudinal crack defect in a cylindrical shell for a number of common cases, in terms of thickness-to-radius ratio, crack size ratio and crack aspect ratio.

The evaluation of stress intensity factor is determined through J-integral parameter found using a finite element analysis with a specially meshed strategy incorporating the crack. A comparison is made against stress intensity factor provided by the code.

A good agreement is obtained with percent error of 2.13 percent for low aspect ratio crack, and 0.57 percent for high aspect ratio crack. Furthermore, a study has been carried out using the methodology for 160 cases, covering both cases already available in the code and other cases of crack in cylindrical shells. The result can be used as a complement to the existing tabular data available in the code for Level 2 assessment, to be used for integrity analysis of damaged cylindrical shells based on the FAD criteria.

The result can be used as a complement to the existing tabular data available in the API 579 code for Level 2 assessment, to be used for integrity analysis of damaged cylindrical shells based on the FAD criteria. New equations were generated based on finite element analysis and can be used for Level 3 assessment of the code.

USING the general theory of cylindrical shells, expressions have been derived for the maximum bending moment and shearing force in vessels closed at one end and subjected internally to (a) gas pressure, (b) hydrostatic pressure. The method has been used by S. Timoshenko (Theory of Plates and Shells, McGraw‐Hill, pp. 412–3) for the special case where one end of the vessels is built into a rigid foundation.

The rate of diffusion‐controlled corrosion of the copper walls of a cylindrical agitated vessel in acidified FeCl3 solution was studied by measuring the weight loss and the increase of Cu2+ concentration with time using iodometry. Variables studied were impeller rotation speed, physical properties of the blank solution and oil concentration in the emulsion. The rate of dissolution of copper was found to increase with increase in impeller speed according to the equation: K = a′ V0.1, where K is the mass transfer coefficient, a′ is a function of oil concentration; V is the linear velocity of the impeller. The mass transfer coefficient of the corrosion process in blank solution was related to other variables by the equation: Sh = 0.000575 Re0.1 Sc0.33, where Sh is the Sherwood number, Re the Reynolds number and Sc Schmidt number. This equation could be used in the design stage, to calculate the thickness of the vessel which covers a certain life span in service under a given set of operating conditions.

The objective of the present work is to present the design optimization of composite cylindrical shell subjected to an axial compressive load and lateral pressure.

A novel optimization method is developed to predict the optimal fiber orientation in composite cylindrical shell. The optimization is carried out by coupling analytical and finite element (FE) results with a genetic algorithm (GA)-based optimization scheme developed in MATLAB. Linear eigenvalue were performed to evaluate the buckling behaviour of composite cylinders. In analytical part, besides the buckling analysis, Tsai-Wu failure criteria are employed to analyse the failure of the composite structure.

The optimal result obtained through this study is compared with traditionally used laminates with 0, 90, ±45 orientation. The results suggest that the application of this novel optimization algorithm leads to an increase of 94% in buckling strength.

The proposed optimal fiber orientation can provide a practical and efficient way for the designers to evaluate the buckling pressure of the composite shells in the design stage.