Estimation of Elastic Buckling Strength of a Non-Spherical Tank in the Partially Filled Condition

2017 ◽  
Author(s):  
Atsushi Sano ◽  
Naoya Matsubara ◽  
Naruyoshi Izumi ◽  
Masahiko Fujikubo
Keyword(s):  
Strength Analysis ◽  
Toroidal Shell ◽  
Elastic Buckling ◽  
Stress Distributions ◽  
Element Analysis ◽  
Initial Shape ◽  
Buckling Strength ◽  
Buckling Stress ◽  
Spherical Tank ◽  
Shell Finite Element

A method of estimating elastic buckling strength of a non-spherical tank intended for the use in LNG carriers is presented. Partially filled condition that causes combined meridional tension and circumferential compression is considered. Analytical expression of pre-buckling stress distributions is derived based on membrane shell theory. These stresses are applied to the elastic buckling strength analysis employing Hutchinson’s solution for a toroidal shell segment under similar stress condition. The buckling strength of a spherical shell is highly sensitive to initial shape imperfections, but these are not considered as a most fundamental case. The predicted stress distributions and elastic buckling strength are compared with those calculated by the 3D shell finite element analysis.

scholarly journals Flexural Elastic Buckling Stress of Batten Type Light Gauge Built-Up Member

2017 ◽  
Vol 25 (2) ◽  
pp. 161-172 ◽  
Author(s):  
Kazuya Mitsui ◽  
Atsushi Sato
Keyword(s):  
Slenderness Ratio ◽  
Shear Wall ◽  
Elastic Buckling ◽  
Test Results ◽  
Current Standard ◽  
Buckling Strength ◽  
Buckling Stress ◽  
Strength Based ◽  
Energy Equilibrium ◽  
Compression Member

Abstract In Japan, built-up member composed with light gauge is used for studs of shear wall. Flexural buckling stress of built-up compression member is evaluated by effective slenderness ratio. The effective slenderness ratio of light gauge built-up compression member is proposed for heavy sections; however, it is not verified that it can be adopted in light gauge. In this paper, full scale testing of light gauge built-up members are conducted. From the test results, it is shown that current Standard overestimates the buckling strength. Based on energy equilibrium theory, modified effective slenderness ratio for light gauge built-up member is derived. The validity of the modified effective slenderness ratio is shown with test results.

Long Wavelength Buckling of Cubic Open-Cell Foams Subjected to Uniaxial Compression

2007 ◽  
Vol 353-358 ◽  
pp. 583-586 ◽  
Author(s):  
Dai Okumura ◽  
Atsushi Okada ◽  
Nobutada Ohno
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Uniaxial Compression ◽  
Elastic Buckling ◽  
Element Analysis ◽  
Open Cell ◽  
Buckling Strength ◽  
Long Wavelength ◽  
Onset Condition ◽  
Open Cell Foams

In this study, the elastic buckling strength of cubic open-cell foams subjected to uniaxial compression is investigated using the homogenization framework developed by the present authors (Ohno et al., JMPS 2002; Okumura et al., JMPS 2004). First of all, based on the framework, the microscopic bifurcation and macroscopic instability of cubic open-cell foams are numerically analyzed by performing finite element analysis. It is thus shown that long wavelength buckling is the primary mode and occurs just after the onset of macroscopic instability. Then, a solution for predicting the stress of long wavelength buckling is analytically derived from the onset condition of macroscopic instability. The validity of this analytical solution is demonstrated by the finite element results.

Buckling Strength of Towers Having Partial Metal Loss on Shell Under Overturning Moment

2015 ◽  
Author(s):  
Masayuki Ozaki ◽  
Atsushi Yamaguchi ◽  
Takuyo Kaida ◽  
Satoshi Nagata
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Metal Loss ◽  
Element Analysis ◽  
Buckling Strength ◽  
Buckling Stress ◽  
Critical Issues ◽  
Process Plants ◽  
Overturning Moment ◽  
Good Agreement

Reliability of Fitness-For-Service assessment has become more important especially for the aged pressure equipment such as towers in process plants put in service operation over decades. The effects of partial metal loss on buckling strength of the towers subject to overturning moment due to seismic or wind load are one of the critical issues to be clarified. The present paper simulates the buckling strength of towers under overturning moment by means of finite element analysis considering the condition that the shell has suffered from partial metal loss, and evaluates the validity of the buckling stress formulae of API 579-1/ASME FFS-1, NASA, and Donnell. It has been demonstrated that the buckling strength predicted by API formulae shows fairly good agreement with that simulated by finite element analysis. Finite element analysis results have shown that the axial length of metal loss does not affect the buckling stress very much while the buckling stress depends on the circumferential width of metal loss. It has been revealed that the API formulae underestimate the buckling stress when the width of metal loss is smaller than about 30 deg. The paper proposes the modification to the API formulae in this condition that gives more accurate buckling stress than the original formulae.

scholarly journals Impact of structural uncertainties on the buckling strength of cylindrical GLARE panels subjected to uniform compression

2021 ◽  
Vol 349 ◽  
pp. 01003
Author(s):  
Costas Kalfountzos ◽  
George Bikakis ◽  
Efstathios Theotokoglou
Keyword(s):  
Latin Hypercube Sampling ◽  
Buckling Load ◽  
Design System ◽  
Elastic Buckling ◽  
Random Input ◽  
Element Analysis ◽  
Uniform Compression ◽  
Deterministic Analysis ◽  
Buckling Strength ◽  
Input Variables

The objective of this article is the investigation of the elastic buckling strength of cylindrical simply supported GLARE (GLAss REinforced) panels subjected to axial compression using probabilistic analysis methods, so that the effect of uncertainties associated with material properties and dimensions of the panels on their elastic buckling load can be evaluated. The mechanical properties of aluminum along with the dimensions of aluminum and unidirectional (UD) glass-epoxy layers are considered to be random input variables whereas the critical buckling load is defined as a random output parameter. The employed eigenvalue buckling analysis and the probabilistic finite element analysis were carried out with ANSYS software. The Probabilistic Design System (PDS), along with the Monte Carlo Simulation and the Latin Hypercube Sampling method were used for the calculations. It is found that the thickness of aluminum layers has the strongest effect on the buckling strength, among the considered random input variables. It is also demonstrated that there is a considerable probability for the buckling load of GLARE panels to be overestimated when a deterministic analysis is conducted.

Pseudo-Cylindrical Shells: A New Concept for Undersea Structures

1977 ◽  
Vol 99 (2) ◽  
pp. 485-492 ◽  
Author(s):  
R. H. Knapp
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Cylindrical Shells ◽  
Elastic Buckling ◽  
Stress Distributions ◽  
Geometrical Configuration ◽  
Element Analysis ◽  
Stability Properties ◽  
Buckling Resistance ◽  
Structural Concept

A new structural concept is proposed which offers promising new alternatives to the design of undersea pressure-resisting structures. This novel geometrical configuration consists of a concave polyhedral cylinder which exhibits stress distributions similar to those in “true” cylinders, but exhibits markedly higher elastic buckling resistance. Several undersea applications of this concept are suggested. Geometrical, stress, and stability properties have been examined by experimental and finite-element analysis.

Buckling of Single-Deck Floating Roofs in Aboveground Oil Storage Tanks Due to Circumferential Bending Load

2006 ◽  
Author(s):  
Shoichi Yoshida ◽  
Kazuhiro Kitamura
Keyword(s):  
Large Diameter ◽  
Bending Moment ◽  
Bottom Plate ◽  
Storage Tanks ◽  
Element Analysis ◽  
Buckling Strength ◽  
Structural Problems ◽  
Oil Storage ◽  
Bending Load ◽  
Shell Finite Element

The 2003 Tokachi-Oki earthquake caused severe damage to oil storage tanks due to liquid sloshing. Six single-deck floating roofs had experienced structural problems as evidenced by sinking failure in large diameter tanks at the refinery at Tomakomai, Japan. The pontoon of floating roof might be buckled due to circumferential bending moment during the sloshing. The content in the tank was spilled on the floating roof from small failures which were caused in the rap welding joints of pontoon bottom plate by the buckling. Then the floating roof began to lose buoyancy and submerged into the content slowly. The failure of the roof expanded gradually in the sinking process. It is presumed that the initial small failures were caused by the elastic buckling of the pontoon due to circumferential bending moment. This paper presents the buckling strength of the pontoon using axisymmetric shell finite element analysis. Linear elastic bifurcation buckling analysis is carried out and the buckling characteristics of the pontoon are investigated. The result shows that the thickness of both pontoon roof and bottom plates have significantly affect the buckling strength.

Finite Element Analysis of Tire/Rim Interface Forces Under Braking and Cornering Loads

1992 ◽  
Vol 20 (2) ◽  
pp. 83-105 ◽  
Author(s):  
J. P. Jeusette ◽  
M. Theves
Keyword(s):  
Finite Element ◽  
Shear Stress ◽  
Contact Pressure ◽  
Element Model ◽  
Shear Stresses ◽  
Detailed Knowledge ◽  
Stress Distributions ◽  
Element Analysis ◽  
Plane Shear ◽  
Normal Contact

Abstract During vehicle braking and cornering, the tire's footprint region may see high normal contact pressures and in-plane shear stresses. The corresponding resultant forces and moments are transferred to the wheel. The optimal design of the tire bead area and the wheel requires a detailed knowledge of the contact pressure and shear stress distributions at the tire/rim interface. In this study, the forces and moments obtained from the simulation of a vehicle in stationary braking/cornering conditions are applied to a quasi-static braking/cornering tire finite element model. Detailed contact pressure and shear stress distributions at the tire/rim interface are computed for heavy braking and cornering maneuvers.

scholarly journals Comparison of Tooth- and Bone-Borne Appliances on the Stress Distributions and Displacement Patterns in the Facial Skeleton in Surgically Assisted Rapid Maxillary Expansion—A Finite Element Analysis (FEA) Study

Materials ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1152
Author(s):  
Rafał Nowak ◽  
Anna Olejnik ◽  
Hanna Gerber ◽  
Roman Frątczak ◽  
Ewa Zawiślak
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Three Dimensional ◽  
Element Model ◽  
Rapid Maxillary Expansion ◽  
Stress Distributions ◽  
Maxillary Expansion ◽  
Facial Skeleton ◽  
Element Analysis ◽  
Maxillary Constriction

The aim of this study was to compare the reduced stresses according to Huber’s hypothesis and the displacement pattern in the region of the facial skeleton using a tooth- or bone-borne appliance in surgically assisted rapid maxillary expansion (SARME). In the current literature, the lack of updated reports about biomechanical effects in bone-borne appliances used in SARME is noticeable. Finite element analysis (FEA) was used for this study. Six facial skeleton models were created, five with various variants of osteotomy and one without osteotomy. Two different appliances for maxillary expansion were used for each model. The three-dimensional (3D) model of the facial skeleton was created on the basis of spiral computed tomography (CT) scans of a 32-year-old patient with maxillary constriction. The finite element model was built using ANSYS 15.0 software, in which the computations were carried out. Stress distributions and displacement values along the 3D axes were found for each osteotomy variant with the expansion of the tooth- and the bone-borne devices at a level of 0.5 mm. The investigation showed that in the case of a full osteotomy of the maxilla, as described by Bell and Epker in 1976, the method of fixing the appliance for maxillary expansion had no impact on the distribution of the reduced stresses according to Huber’s hypothesis in the facial skeleton. In the case of the bone-borne appliance, the load on the teeth, which may lead to periodontal and orthodontic complications, was eliminated. In the case of a full osteotomy of the maxilla, displacements in the buccolingual direction for all the variables of the bone-borne appliance were slightly bigger than for the tooth-borne appliance.

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