Composite Construction for Resisting External Pressure

2009 ◽  
Author(s):  
C.D. Goode
Keyword(s):  
External Pressure ◽  
Composite Construction

Buckling of Long Sandwich Cylindrical Shells Under External Pressure

2004 ◽  
Vol 72 (4) ◽  
pp. 493-499 ◽  
Author(s):  
G. A. Kardomateas ◽  
G. J. Simitses
Keyword(s):  
Transverse Shear ◽  
Shell Thickness ◽  
Shell Theory ◽  
Cylindrical Shells ◽  
Three Dimensional ◽  
Stability Loss ◽  
External Pressure ◽  
Composite Construction ◽  
The Core ◽  
Sandwich Construction

An elasticity solution to the problem of buckling of sandwich long cylindrical shells subjected to external pressure is presented. In this context, the structure is considered a three-dimensional body. All constituent phases of the sandwich structure, i.e., the facings and the core, are assumed to be orthotropic. The loading is a uniform hydrostatic pressure, which means that the loading remains normal to the deflected surface during the buckling process. Results are produced for laminated facings, namely, boron/epoxy, graphite/epoxy and kevlar/epoxy laminates with 0deg orientation with respect to the hoop direction, and for alloy-foam core. Shell theory results are generated with and without accounting for the transverse shear effect. Two transverse shear correction approaches are compared, one based only on the core, and the other based on an effective shear modulus that includes the face sheets. The results show that the shell theory predictions without transverse shear can produce highly non-conservative results on the critical pressure, but the shell theory formulas with transverse shear correction produce reasonable results with the shear correction based on the core only being in general conservative (i.e., critical load below the elasticity value). The results are presented for four mean radius over shell thickness ratios, namely 15, 30, 60, and 120 in order to assess the effect of shell thickness (and hence that of transverse shear). For the same thickness, the differences between elasticity and shell theory predictions become larger as the mean radius over thickness ratio is decreased. A comparison is also provided for the same shell with homogeneous composite construction. It is shown that the sandwich construction shows much larger differences between elasticity and shell theory predictions than the homogeneous composite construction. The solution presented herein provides a means of a benchmark for accurately assessing the limitations of shell theories in predicting stability loss in sandwich shells.

Trust: A National Project

2015 ◽  
pp. 138-146
Author(s):  
N. Rozinskaya ◽  
I. Rozinskiy
Keyword(s):  
Social Capital ◽  
Civil Society ◽  
Everyday Life ◽  
Western Europe ◽  
External Pressure ◽  
National Project ◽  
Low Level ◽  
General Trust

This article deals with the genesis of general trust and social capital in contemporary Russia, which faces the external pressure. The low level of general trust is noted, its economic, social and everyday life implications are considered, an explanation of Russia’s lower than in western Europe level of trust is provided. Considering society’s level of trust and social capital as externalia, the authors conclude that there is a necessity to "produce" trust intentionally. Promotion of collective charity is proposed as a mechanism of such "production". It is stressed that in order to activate the potential of trust in a society, there is a need for ideological and symbolic basis linked to its history. Russian People’s Unity Day, understood as the birthday of Russian civil society, is proposed to be used in this respect.

Under Pressure: Mechanochemical Effects on Structure and Ion Conduction in the Sodium-Ion Solid Electrolyte Na3PS4

2020 ◽  
Author(s):  
Theodosios Famprikis ◽  
O. Ulas Kudu ◽  
James Dawson ◽  
Pieremanuele Canepa ◽  
François Fauth ◽  
...  
Keyword(s):  
Ionic Conductivity ◽  
Mechanochemical Synthesis ◽  
Activation Volume ◽  
External Pressure ◽  
Sodium Ion ◽  
Variable Pressure ◽  
Ion Conductor ◽  
Ceramic Synthesis ◽  
Solid State Batteries ◽  
Fast Ion

<div> <p>Fast-ion conductors are critical to the development of solid-state batteries. The effects of mechanochemical synthesis that lead to increased ionic conductivity in an archetypical sodium-ion conductor Na<sub>3</sub>PS<sub>4</sub> are not fully understood. We present here a comprehensive analysis based on diffraction (Bragg, pair distribution function), spectroscopy (impedance, Raman, NMR, INS) and <i>ab-initio</i> simulations aimed at elucidating the synthesis-property relationships in Na<sub>3</sub>PS<sub>4</sub>. We consolidate previously reported interpretations about the local structure of ball-milled samples, underlining the sodium disorder and showing that a local tetragonal framework more accurately describes the structure than the originally proposed cubic one. Through variable-pressure impedance spectroscopy measurements, we report for the first time the activation volume for Na<sup>+</sup> migration in Na<sub>3</sub>PS<sub>4</sub>, which is ~30% higher for the ball-milled samples. Moreover, we show that the effect of ball-milling on increasing the ionic conductivity of Na<sub>3</sub>PS<sub>4</sub> to ~10<sup>-4</sup> S/cm can be reproduced by applying external pressure on a sample from conventional high temperature ceramic synthesis. We conclude that the key effects of mechanochemical synthesis on the properties of solid electrolytes can be analyzed and understood in terms of pressure, strain and activation volume.</p> </div>

FRAUD TRIANGLE ANALYSES IN DETECTING FRAUDULENT FINANCIAL STATEMENT USING FRAUD SCORE MODEL

2020 ◽  
Vol 25 (1) ◽  
pp. 29-44
Author(s):  
Mariati ◽  
Emmy Indrayani
Keyword(s):  
Financial Stability ◽  
Linear Regression Analysis ◽  
Financial Statements ◽  
Multiple Linear Regression Analysis ◽  
External Pressure ◽  
Financial Statement ◽  
Fraud Triangle ◽  
Financial Statement Fraud ◽  
Financial Condition ◽  
Score Model

Company’s financial condition reflected in the financial statements. However, there are many loopholes in the financial statements which can become a chance for the management and certain parties to commit fraud on the financial statements. This study aims to detect financial statement fraud as measured using fraud score model that occurred in issuers entered into the LQ-45 index in 2014-2016 with the use of six independent variables are financial stability, external pressure, financial target, nature of industry, ineffective monitoring and rationalization. This study using 27 emiten of LQ-45 index during 2014-2016. However, there are some data outlier that shall be removed, thus sample results obtained 66 data from 25 companies. Multiple linear regression analysis were used in this study. The results showed that the financial stability variables (SATA), nature of industry (RECEIVBLE), ineffective monitoring (IND) and rationalization (ITRENDLB) proved to be influential or have the capability to detect financial statement fraud. While the external pressure variables (DER) and financial target (ROA) are not able to detect the existence of financial statement fraud. Simultaneously all variables in this study were able to detect significantly financial statement fraud.

Sign in / Sign up

Export Citation Format

Share Document