scholarly journals The indentation of pressurized elastic shells: from polymeric capsules to yeast cells

2011 ◽  
Vol 9 (68) ◽  
pp. 448-455 ◽  
Author(s):  
Dominic Vella ◽  
Amin Ajdari ◽  
Ashkan Vaziri ◽  
Arezki Boudaoud
Keyword(s):  
Internal Pressure ◽  
Osmotic Pressure ◽  
Elastic Shell ◽  
Turgor Pressure ◽  
Plant Cells ◽  
Pressure Vessels ◽  
Yeast Cells ◽  
Experimental Investigations ◽  
Oil Refineries ◽  
Elastic Capsules

Pressurized elastic capsules arise at scales ranging from the 10 m diameter pressure vessels used to store propane at oil refineries to the microscopic polymeric capsules that may be used in drug delivery. Nature also makes extensive use of pressurized elastic capsules: plant cells, bacteria and fungi have stiff walls, which are subject to an internal turgor pressure. Here, we present theoretical, numerical and experimental investigations of the indentation of a linearly elastic shell subject to a constant internal pressure. We show that, unlike unpressurized shells, the relationship between force and displacement demonstrates two linear regimes. We determine analytical expressions for the effective stiffness in each of these regimes in terms of the material properties of the shell and the pressure difference. As a consequence, a single indentation experiment over a range of displacements may be used as a simple assay to determine both the internal pressure and elastic properties of capsules. Our results are relevant for determining the internal pressure in bacterial, fungal or plant cells. As an illustration of this, we apply our results to recent measurements of the stiffness of baker's yeast and infer from these experiments that the internal osmotic pressure of yeast cells may be regulated in response to changes in the osmotic pressure of the external medium.

A Comprehensive Study on Burst Pressure Performance of Aluminum Liner for Hydrogen Storage Vessels

2021 ◽  
Vol 143 (4) ◽  
Author(s):  
Serkan Kangal ◽  
A. Harun Sayı ◽  
Ozan Ayakdaş ◽  
Osman Kartav ◽  
Levent Aydın ◽  
...  
Keyword(s):  
Internal Pressure ◽  
Axial Strain ◽  
Cylindrical Part ◽  
Pressure Vessels ◽  
Fe Analysis ◽  
Burst Pressure ◽  
Experimental Investigations ◽  
Fe Model ◽  
Stress Criterion ◽  
Analytical Approaches

Abstract This paper presents a comparative study on the burst pressure performance of aluminum (Al) liner for type-III composite overwrapped pressure vessels (COPVs). In the analysis, the vessels were loaded with increasing internal pressure up to the burst pressure level. In the analytical part of the study, the burst pressure of the cylindrical part was predicted based on the modified von Mises, Tresca, and average shear stress criterion (ASSC). In the numerical analysis, a finite element (FE) model was established in order to predict the behavior of the vessel as a function of increasing internal pressure and determine the final burst. The Al pressure vessels made of Al-6061-T6 alloy with a capacity of 5 L were designed. The manufacturing of the metallic vessels was purchased from a metal forming company. The experimental study was conducted by pressurizing the Al vessels until the burst failure occurred. The radial and axial strain behaviors were monitored at various locations on the vessels during loading. The results obtained through analytical, numerical, and experimental work were compared. The average experimental burst pressure of the vessels was found to be 279 bar. The experimental strain data were compared with the results of the FE analysis. The results indicated that the FE analysis and ASSC-based elastoplastic analytical approaches yielded the best predictions which are within 2.2% of the experimental burst failure values. It was also found that the elastic analysis underestimated the burst failure results; however, it was effective for determining the critical regions over the vessel structure. The strain behavior of the vessels obtained through experimental investigations was well correlated with those predicted through FE analysis.

Very thin torispherical pressure vessel ends under internal pressure: Test procedure and typical results

1981 ◽  
Vol 16 (3) ◽  
pp. 171-186 ◽  
Author(s):  
P Stanley ◽  
T D Campbell
Keyword(s):  
Stainless Steel ◽  
Internal Pressure ◽  
Elastic Stress ◽  
Test Procedure ◽  
Pressure Vessels ◽  
Time Dependent ◽  
Test Installation ◽  
Stress Indices ◽  
Pressure Test ◽  
Strain Data

Very thin cylindrical pressure vessels with torispherical end-closures have been tested under internal pressure until buckles developed in the knuckles of the ends. These were prototype vessels in an austenitic stainless steel. The preparation of the ends and the closed test vessels is outlined, and the instrumentation, test installation, and test procedure are described. Results are given and discussed for three typical ends (diameters 54, 81, and 108in.; thickness to diameter ratios 0.00237, 0.00158, and 0.00119). These include measured thickness and curvature distributions, strain data and the derived elastic stress indices, and pole deflection measurements. Some details of the observed time-dependent plasticity (or ‘cold creep’) are given. Details of two types of buckle that developed eventually in the vessel ends are also reported.

A Noncyclic Method for Determination of Accumulated Strain in Stainless Steel 304 Pressure Vessels

2014 ◽  
Vol 136 (6) ◽  
Author(s):  
Gongfeng Jiang ◽  
Gang Chen ◽  
Liang Sun ◽  
Yiliang Zhang ◽  
Xiaoliang Jia ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Internal Pressure ◽  
Pressure Vessel ◽  
Peak Stress ◽  
Pressure Vessels ◽  
Experimental Results ◽  
Elastic Domain ◽  
Ratcheting Strain ◽  
Stainless Steel 304 ◽  
Accumulated Strain

Experimental results of uniaxial ratcheting tests for stainless steel 304 (SS304) under stress-controlled condition at room temperature showed that the elastic domain defined in this paper expands with accumulation of plastic strain. Both ratcheting strain and viscoplastic strain rates reduce with the increase of elastic domain, and the total strain will be saturated finally. If the saturated strain and corresponded peak stress of different experimental results under the stress ratio R ≥ 0 are plotted, a curve demonstrating the material shakedown states of SS304 can be constituted. Using this curve, the accumulated strain in a pressure vessel subjected to cyclic internal pressure can be determined by only an elastic-plastic analysis, and without the cycle-by-cycle analysis. Meanwhile, a physical experiment of a thin-walled pressure vessel subjected to cyclic internal pressure has been carried out to verify the feasibility and effectiveness of this noncyclic method. By comparison, the accumulated strains evaluated by the noncyclic method agreed well with those obtained from the experiments. The noncyclic method is simpler and more practical than the cycle-by-cycle method for engineering design.

A Single Technically Consistent Design Formula for the Thickness of Cylindrical Sections Under Internal Pressure

2006 ◽  
Vol 129 (1) ◽  
pp. 211-215 ◽  
Author(s):  
John D. Fishburn
Keyword(s):  
Experimental Data ◽  
Internal Pressure ◽  
State Of The Art ◽  
Original Data ◽  
Pressure Vessels ◽  
Time Dependent ◽  
Design Codes ◽  
Recent Developments ◽  
Current Design ◽  
Single Formula

Within the current design codes for boilers, piping, and pressure vessels, there are many different equations for the thickness of a cylindrical section under internal pressure. A reassessment of these various formulations, using the original data, is described together with more recent developments in the state of the art. A single formula, which can be demonstrated to retain the same design margin in both the time-dependent and time-independent regimes, is shown to give the best correlation with the experimental data and is proposed for consideration for inclusion in the design codes.

scholarly journals MOS1 Osmosensor of Metarhizium anisopliae Is Required for Adaptation to Insect Host Hemolymph

2007 ◽  
Vol 7 (2) ◽  
pp. 302-309 ◽  
Author(s):  
Chengshu Wang ◽  
Zhibing Duan ◽  
Raymond J. St. Leger
Keyword(s):  
Osmotic Pressure ◽  
Stress Responses ◽  
Metarhizium Anisopliae ◽  
Turgor Pressure ◽  
Adaptor Proteins ◽  
Reverse Transcription Pcr ◽  
Oxidative Stresses ◽  
Hyphal Bodies ◽  
Increased Sensitivity ◽  
Src Homology

ABSTRACT Entomopathogenic fungi such as Metarhizium anisopliae infect insects by direct penetration of the cuticle, after which the fungus adapts to the high osmotic pressure of the hemolymph and multiplies. Here we characterize the M. anisopliae Mos1 gene and demonstrate that it encodes the osmosensor required for this process. MOS1 contains transmembrane regions and a C-terminal Src homology 3 domain similar to those of yeast osmotic adaptor proteins, and homologs of MOS1 are widely distributed in the fungal kingdom. Reverse transcription-PCR demonstrated that Mos1 is up-regulated in insect hemolymph as well as artificial media with high osmotic pressure. Transformants containing an antisense vector directed to the Mos1 mRNA depleted transcript levels by 80%. This produced selective alterations in regulation of genes involved in hyphal body formation, cell membrane stiffness, and generation of intracellular turgor pressure, suggesting that these processes are mediated by MOS1. Consistent with a role in stress responses, transcript depletion of Mos1 increased sensitivity to osmotic and oxidative stresses and to compounds that interfere with cell wall biosynthesis. It also disrupted developmental processes, including formation of appressoria and hyphal bodies. Insect bioassays confirmed that Mos1 knockdown significantly reduces virulence. Overall, our data show that M. anisopliae MOS1 mediates cellular responses to high osmotic pressure and subsequent adaptations to colonize host hemolymph.

Fracture of laminated woven GFRP composite pressure vessels under combined low-velocity impact and internal pressure

2018 ◽  
Vol 18 (4) ◽  
pp. 1715-1728 ◽  
Author(s):  
Shokrollah Sharifi ◽  
Soheil Gohari ◽  
Masoumeh Sharifiteshnizi ◽  
Reza Alebrahim ◽  
Colin Burvill ◽  
...  
Keyword(s):  
Internal Pressure ◽  
Pressure Vessels ◽  
Low Velocity Impact ◽  
Low Velocity ◽  
Velocity Impact ◽  
Gfrp Composite ◽  
Composite Pressure Vessels

Statics and Dynamics of Elastic Shells with Cutouts —A Review

1974 ◽  
Vol 18 (02) ◽  
pp. 113-126
Author(s):  
J. Pattabiraman ◽  
V. Ramamurti ◽  
D. V. Reddy
Keyword(s):  
Dynamic Loading ◽  
Nuclear Reactors ◽  
High Reliability ◽  
Pressure Vessels ◽  
Experimental Investigations ◽  
Concentrated Loads ◽  
Stress Concentrations ◽  
Elastic Shells ◽  
Statics And Dynamics ◽  
Static And Dynamic Loading

The purpose of this survey is to give a review of the methods and results of analytical and experimental investigations for stress concentrations in thin elastic shells subjected to static and dynamic loading. The increasing use of higher-strength materials in the design of pressure vessels, aircraft, ships, and nuclear reactors with high reliability necessitates more precise analyses in the regions of cutouts and concentrated loads.

Maximum Condensable Pressure in a Sealed Container With Arbitrary Temperature Distribution

2020 ◽  
Author(s):  
J. I. Watjen ◽  
M. T. Schifano ◽  
M. N. Sexton
Keyword(s):  
Temperature Distribution ◽  
Internal Pressure ◽  
Strong Relationship ◽  
Pressure Vessels ◽  
Large Temperature ◽  
Internal Temperature ◽  
Seal Integrity ◽  
Arbitrary Temperature ◽  
Vapor Mixtures ◽  
Saturated Boiling

Abstract Pressure vessels and sealed canisters are designed to maintain seal integrity under a maximum internal pressure. When the temperature inside the canister rises, the internal pressure rises accordingly. The presence of condensable liquid-vapor mixtures can create a strong relationship between the pressure and temperature. An isothermal container admits a straightforward thermodynamic pressure calculation; however, large temperature gradients inside the container require complex multiphase conjugate heat transfer calculations to predict accurate pressures. A simplified prediction using the peak internal temperature to find the saturated pressure of the condensable fluid may introduce unrealistic pressures when significant fluid mass exists in a cooler location of the container. This work presents methodology to calculate the pressure of a condensable fluid in a sealed container with large internal temperature differences using a two-temperature approach to predict saturated boiling and superheating of the vapor phase. An arbitrary temperature distribution allows for pressure calculations by considering the expected location of the liquid mass and the peak internal temperature. An enthalpy balance provides the effects of the temperature distribution and the peak pressure condition is easily predicted using the proposed method. This work provides a means to calculate the maximum internal pressure of a sealed container with a condensable fluid without the need for complex multiphase computer modeling.

Sign in / Sign up

Export Citation Format

Share Document