Implosion tests of aluminium-alloy ring-stiffened cylinders subjected to external hydrostatic pressure

2021 ◽  
Vol 78 ◽  
pp. 102980
Author(s):  
Teguh Muttaqie ◽  
Sang Hyun Park ◽  
Jung Min Sohn ◽  
Sang-Rai Cho ◽  
In Sik Nho ◽  
...  
Keyword(s):  
Hydrostatic Pressure ◽  
Aluminium Alloy ◽  
External Hydrostatic Pressure

Implosion Tests of Aluminium Alloy Tubes Under External Hydrostatic Pressure

2018 ◽  
Author(s):  
Teguh Muttaqie ◽  
Jung-Min Sohn ◽  
Sang-Rai Cho ◽  
Sang-Hyun Park ◽  
Gulgi Choi ◽  
...  
Keyword(s):  
Hydrostatic Pressure ◽  
Aluminium Alloy ◽  
Pressure Pulse ◽  
Deep Ocean ◽  
External Hydrostatic Pressure ◽  
Nitrogen Gas ◽  
Pressure Drops ◽  
Hydrostatic Loading ◽  
Quantitative Validation ◽  
Alloy 6061

This paper reports the implosion tests of aluminium alloy 6061-T6 tube models under external hydrostatic pressure. The investigations took an emphasis on how to replicate the deep-ocean pressure environment of the implosion phenomenon on a laboratory scale. The parameters which affected the implosion pressure pulse were also observed. Two kinds of implosion tests were conducted, namely, dynamic implosion test and quasi-static implosion test. The pressure drops in the post ultimate regime was negligible in the dynamic implosion test which performed using compressed nitrogen gas. The pressure and strain histories of the both implosion tests were compared and analysed. In addition, non-linear FE analyses for quantitative validation and comparison of the imploded tubes were conducted. The numerical quantities including the initial ovality, thickness unevenness, and air backed fluid cavity parameters are investigated to propose more realistic imploded tubes induced by the external hydrostatic loading.

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

2012 ◽  
Vol 134 (4) ◽  
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.

scholarly journals OPTIMUM BUCKLING DESIGN OF CYLINDRICAL STIFFENER SHELL UNDER EXTERNAL HYDROSTATIC PRESSURE

2018 ◽  
Vol 18 (2) ◽  
pp. 239-252 ◽  
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.

Plastic buckling of ring-stiffened conical shells under external hydrostatic pressure

2005 ◽  
Vol 32 (1) ◽  
pp. 21-36 ◽  
Author(s):  
Carl T.F. Ross ◽  
Andrew P.F. Little ◽  
Kehinde A. Adeniyi
Keyword(s):  
Hydrostatic Pressure ◽  
External Hydrostatic Pressure ◽  
Plastic Buckling ◽  
Conical Shells
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