Exact and simplified estimations for elastic buckling pressures of structural pipe-in-pipe cross sections under external hydrostatic pressure

Two machined models were collapsed under external hydrostatic pressure to determine the elastic buckling strength of complete prolate spheroidal shells. The test results demonstrated that collapse pressures 40 percent greater than predicted by available theory can be achieved for a prolate spheroidal shell with a major to minor axis ratio of 3.0 and a thickness to diameter ratio of 0.015.

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Study of Ductile-to-Brittle Transition in Single Grit Diamond Scribing of Silicon: Application to Wire Sawing of Silicon Wafers

Journal of Engineering Materials and Technology ◽

10.1115/1.4006177 ◽

2012 ◽

Vol 134 (4) ◽

Cited By ~ 55

Author(s):

Hao Wu ◽

Shreyes N. Melkote

Keyword(s):

Hydrostatic Pressure ◽

Silicon Wafers ◽

Depth Of Cut ◽

Critical Depth ◽

External Hydrostatic Pressure ◽

Tensile Stresses ◽

Brittle Transition ◽

Ductile Mode Cutting ◽

Critical Depth Of Cut ◽

Ductile To Brittle Transition

The ductile-to-brittle cutting mode transition in single grit diamond scribing of monocrystalline silicon is investigated in this paper. Specifically, the effects of scriber tip geometry, coefficient of friction, and external hydrostatic pressure on the critical depth of cut associated with ductile-to-brittle transition and crack generation are studied via an eXtended Finite Element Method (XFEM) based model, which is experimentally validated. Scribers with a large tip radius are shown to produce lower tensile stresses and a larger critical depth of cut compared with scribers with a sharp tip. Spherical tipped scribers are shown to generate only surface cracks, while sharp tipped scribers (conical, Berkovich and Vickers) are found to create large subsurface tensile stresses, which can lead to nucleation of subsurface median/lateral cracks. Lowering the friction coefficient tends to increase the critical depth of cut and hence the extent of ductile mode cutting. The results also show that larger critical depth of cut can be obtained under external hydrostatic pressure. This knowledge is expected to be useful in optimizing the design and application of the diamond coated wire employed in fixed abrasive diamond wire sawing of photovoltaic silicon wafers.

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On the elastic buckling of cross-ply composite closed cylindrical shell under hydrostatic pressure

Ocean Engineering ◽

10.1016/j.oceaneng.2021.108633 ◽

2021 ◽

Vol 227 ◽

pp. 108633

Author(s):

Muhammad Imran ◽

Dongyan Shi ◽

Lili Tong ◽

Ahsan Elahi ◽

Muqeem Uddin

Keyword(s):

Cylindrical Shell ◽

Hydrostatic Pressure ◽

Elastic Buckling ◽

Closed Cylindrical Shell

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Buckling of Multiple-Bay Ring-Reinforced Cylindrical Shells Subject to Hydrostatic Pressure

Journal of Applied Mechanics ◽

10.1115/1.4010749 ◽

1953 ◽

Vol 20 (4) ◽

pp. 469-474

Author(s):

W. A. Nash

Keyword(s):

Cylindrical Shell ◽

Hydrostatic Pressure ◽

Strain Energy ◽

Elastic Strain Energy ◽

Middle Surface ◽

Elastic Buckling ◽

Elastic Instability ◽

Total Potential ◽

External Forces ◽

Work Done

Abstract An analytical solution is presented for the problem of the elastic instability of a multiple-bay ring-reinforced cylindrical shell subject to hydrostatic pressure applied in both the radial and axial directions. The method used is that of minimization of the total potential. Expressions for the elastic strain energy in the shell and also in the rings are written in terms of displacement components of a point in the middle surface of the shell. Expressions for the work done by the external forces acting on the cylinder likewise are written in terms of these displacement components. A displacement configuration for the buckled shell is introduced which is in agreement with experimental evidence, in contrast to the arbitrary patterns assumed by previous investigators. The total potential is expressed in terms of these displacement components and is then minimized. As a result of this minimization a set of linear homogeneous equations is obtained. In order that a nontrivial solution to this system of equations exists, it is necessary that the determinant of the coefficients vanish. This condition determines the critical pressure at which elastic buckling of the cylindrical shell will occur.

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OPTIMUM BUCKLING DESIGN OF CYLINDRICAL STIFFENER SHELL UNDER EXTERNAL HYDROSTATIC PRESSURE

THE IRAQI JOURNAL FOR MECHANICAL AND MATERIALS ENGINEERING ◽

10.32852/iqjfmme.vol18.iss2.91 ◽

2018 ◽

Vol 18 (2) ◽

pp. 239-252 ◽

Cited By ~ 1

Author(s):

Rawa Hamed M. Al-Kalali

Keyword(s):

Hydrostatic Pressure ◽

Numerical Optimization ◽

Collapse Load ◽

Ansys Software ◽

External Hydrostatic Pressure ◽

Buckling Mode ◽

Design Elements ◽

Design Variables ◽

Thick Cylinder ◽

Strength Constraints

This paper present an investigation of the collapse load in cylinder shell under uniformexternal hydrostatic pressure with optimum design using finite element method viaANSYS software. Twenty cases are studied inclusive stiffeners in longitudinal and ringstiffeners. Buckling mode shape is evaluated. This paper studied the optimum designgenerated by ANSYS for thick cylinder with external hydrostatic pressure. The primarygoal of this paper was to identify the improvement in the design of cylindrical shell underhydrostatic pressure with and without Stiffeners (longitudinal and ring) with incorporativetechnique of an optimization into ANSYS software. The design elements in this researchwas: critical load, design variable (thickness of shell (TH), stiffener’s width (B) andstiffener’s height (HF). The results obtained illustrated that the objective is minimizedusing technique of numerical optimization in ANSYS with optimum shell thickness andstiffener’s sizes. In all cases the design variables (thickness of shell) was thicker than themonocoque due to a shell’s thicker is essential to achieve the strength constraints. It can beconcluded that cases (17,18,19, and 20) have more than 90% of un-stiffened critical load.The ring stiffeners causes increasing buckling load than un-stiffened and longitudinalstiffened cylinder.

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