Numerical Study on the Stress Concentration Phenomenon in the Membranes of PEMFCs in an Assembled State

A numerical study is performed to investigate the stress concentration phenomenon in a piled embankment during high-speed train passage. In the numerical simulation, the loading of a moving train is first represented in the model as a series of time-varying equivalent concentrated forces vertically acting on the ballast surface, and the explicit finite element method (FEM) is then used to analyze the ballast-embankment-ground system subjected to the equivalent forces. The study shows that owing to the very high stiffness of the piles relative to the soft soil, a majority of the wave energy, which is generated by the passage of wheel axles, is concentrated to the improving piles and transferred down to the stiff soil stratum. By this stress concentration phenomenon, the soft soil surrounding the piles is subjected to less stress, and thus preventing undesirable dynamic effects that could be induced in the soft soil.

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Experimental, numerical and parametric studies on stress concentration factors of T-joints under tension

Advances in Structural Engineering ◽

10.1177/13694332211049994 ◽

2021 ◽

pp. 136943322110499

Author(s):

Feleb Matti ◽

Fidelis Mashiri

Keyword(s):

Finite Element ◽

Stress Concentration ◽

Numerical Study ◽

Hot Spot ◽

Joint Models ◽

Element Analysis ◽

T Joints ◽

Concentration Factors ◽

Stress Concentration Factors ◽

Good Agreement

This paper investigates the behaviour of square hollow section (SHS) T-joints under static axial tension for the determination of stress concentration factors (SCFs) at the hot spot locations. Five empty and corresponding concrete-filled SHS-SHS T-joint connections were tested experimentally and numerically. The experimental investigation was carried out by attaching strain gauges onto the SHS-SHS T-joint specimens. The numerical study was then conducted by developing three-dimensional finite element (FE) T-joint models using ABAQUS finite element analysis software for capturing the distribution of the SCFs at the hot spot locations. The results showed that there is a good agreement between the experimental and numerical SCFs. A series of formulae for the prediction of SCF in concrete-filled SHS T-joints under tension were proposed, and good agreement was achieved between the maximum SCFs in SHS T-joints calculated from FE T-joint models and those from the predicted formulae.

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Modeling of Size Effects in Bending of Perforated Cosserat Plates

Modelling and Simulation in Engineering ◽

10.1155/2017/5246197 ◽

2017 ◽

Vol 2017 ◽

pp. 1-19 ◽

Cited By ~ 1

Author(s):

Roman Kvasov ◽

Lev Steinberg

Keyword(s):

Finite Element ◽

Stress Concentration ◽

Numerical Study ◽

The Finite Element Method ◽

Classical Elasticity ◽

Element Analysis ◽

Plate Deformation ◽

The Finite Element Analysis ◽

Circular Holes ◽

Different Shapes

This paper presents the numerical study of Cosserat elastic plate deformation based on the parametric theory of Cosserat plates, recently developed by the authors. The numerical results are obtained using the Finite Element Method used to solve the parametric system of 9 kinematic equations. We discuss the existence and uniqueness of the weak solution and the convergence of the proposed FEM. The Finite Element analysis of clamped Cosserat plates of different shapes under different loads is provided. We present the numerical validation of the proposed FEM by estimating the order of convergence, when comparing the main kinematic variables with an analytical solution. We also consider the numerical analysis of plates with circular holes. We show that the stress concentration factor around the hole is less than the classical value, and smaller holes exhibit less stress concentration as would be expected on the basis of the classical elasticity.

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Experimental and Numerical Study of Rock Stratum Movement Characteristics in Longwall Mining

Shock and Vibration ◽

10.1155/2019/5041536 ◽

2019 ◽

Vol 2019 ◽

pp. 1-15 ◽

Cited By ~ 6

Author(s):

Wan-rong Liu

Keyword(s):

Stress Concentration ◽

Coal Seam ◽

Longwall Mining ◽

Roof Rock ◽

Numerical Study ◽

High Stress ◽

Engineering Practice ◽

Rock Stratum ◽

Working Face ◽

Coal Wall

The roof fracture is the main cause of coal mine roof accidents. To analyze the law of movement and caving of the roof rock stratum, the roof subsidence displacement, rock stratum stress, and the rock stratum movement law were analyzed by using the methods of the particle discrete element and similar material simulation test. The results show that (1) as the working face advances, regular movement and subsidence appears in the roof rock strata, and the roof subsidence curve forms a typical “U” shape. As the coal seam continues to advance, the maximum subsidence displacement remains basically constant, and the subsidence displacement curves present an asymmetric flat-bottomed distribution. (2) After the coal seam is mined, the overburden forms an arched shape force chain, and the arched strong chain is the path of the overburden transmission force. The farther away from the coal seam, the smaller the stress concentration coefficient is, but it is still in a high stress area, and the stress concentration position moves toward the middle area of the goaf. The stress concentration in front of the coal wall is the source of force that forms the abutment pressure. (3) Above the coal wall towards the goaf, a stepped fracture was formed in the roof rock stratum. The periodic fracture of the rock stratum is the main cause of the periodic weighting of the working face. Understanding the laws of rock movement and stress distribution is of great significance for guiding engineering practice and preventing the roof accidents.

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Investigation of Elliptical Cooling Channels for a Naval Electromagnetic Railgun

Heat Transfer, Part B ◽

10.1115/imece2005-81586 ◽

2005 ◽

Cited By ~ 5

Author(s):

Elizabeth R. Kealey ◽

Peter J. Joyce ◽

Martin Cerza ◽

Andrew N. Smith

Keyword(s):

Heat Transfer ◽

Heat Flux ◽

Stress Concentration ◽

Numerical Study ◽

High Surface ◽

High Surface Area ◽

Structural Aspect ◽

Thermal Testing ◽

Elliptical Cross ◽

Cooling Channels

Elliptical cross sections were examined for the design of cooling channels subject to biaxial and uniaxial compressive loading conditions based on an Electromagnetic (EM) Railgun. Elliptical shapes were considered due to the high surface area available for convection, relatively low impact on the stress distribution, and low stress concentration effect. The heat transfer capability of elliptical channels is maximized based on the applied heat flux and given flow conditions, by treating the channel as a variable area fin and varying the major and minor axis of the elliptical cross-section channel as well as the distance between channels. The optimal channel shape is further constrained by the applied compressive stresses. In order to test the thermal aspect of the design, a representative set of channels were machined into 1/3 scale copper rails using wire EDM. Tests were performed using a steady state heat flux to determine the overall heat transfer coefficient in order to verify the thermal calculations. In order to verify the structural aspect of the design, a numerical study of the stress concentration factors was performed. The results of both the thermal testing and numerical study were found to be in reasonable agreement with the prediction results.

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Improvements for a Hydraulic Excavator's Boom

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.490-491.510 ◽

2014 ◽

Vol 490-491 ◽

pp. 510-513

Author(s):

Sheng Bin Wu ◽

Xiao Bao Liu

Keyword(s):

Finite Element Method ◽

Finite Element ◽

Stress Concentration ◽

Stress Distribution ◽

High Stress ◽

The Finite Element Method ◽

Element Method ◽

Concentration Phenomenon

Focus on stress concentration and high stress area, four improvements were put forward through analyzed a hydraulic excavator's boom with the finite element method under the bucket digging condition. Compared the stress distribution graph, the results show that these schemes can improve the stress concentration phenomenon and the high stress distribution areas. The practices demonstrated the effectiveness to reduce the invalidation rate of hydraulic excavator's boom.

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A Numerical Study on the Control of Horizontal Cracking at the Ends of BS22 Hollow-type PC-girders Utilizing Midas FEA

Journal of Physics Conference Series ◽

10.1088/1742-6596/1996/1/012011 ◽

2021 ◽

Vol 1996 (1) ◽

pp. 012011

Author(s):

Abdul Khaliq Karimi ◽

Bashir Ahmad Aasim ◽

Jun Tomiyama

Keyword(s):

Finite Element Analysis ◽

Finite Element ◽

Stress Concentration ◽

Numerical Study ◽

Crack Size ◽

Analysis Software ◽

Principal Stresses ◽

Element Analysis ◽

Crack Penetration ◽

Strand Debonding

Abstract When the prestressing forces transfer from PC-strands to concrete, a region of stress concentration develops at the ends of pretensioned girders, which often results in horizontal cracking during or just after the detensioning process. In this study, a hollow PC-girder was modeled utilizing a Finite Element Analysis software Midas FEA to identify the horizontal cracking locations in terms of the principal stresses at the end-zone of the hollow PC-girder. Strand-debonding and placing end-zone reinforcements were hired in this work by introducing four cases. The only strand-debonding method could not prevent horizontal end crack penetration. Though the end-zone reinforcements were placed alongside the strand-debonding, this combination could reduce principal stresses to a level that could bring the crack size to a negligible range.

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Predicting Performance of Aluminum - Glass Composite Facade Systems Based on Mechanical Properties of the Connection

Periodica Polytechnica Civil Engineering ◽

10.3311/ppci.9988 ◽

2017 ◽

Author(s):

Maciej Cwyl Warszawska ◽

Andrzej Garbacz ◽

Rafał Michalczyk ◽

Natalia Grzegorzewska

Keyword(s):

Mechanical Properties ◽

Finite Element ◽

Stress Concentration ◽

Mechanical Behavior ◽

Numerical Study ◽

Field Research ◽

Glass Composite ◽

Predicting Performance ◽

Metal Framework ◽

Aluminum Panels

In this paper, an extensive Finite-Element (FE) numerical study is carried out on a glass framing with point mechanical connectors. The models have been calibrated based on literature studies and field research. The simulations have been performed in order to assess the mechanical behavior of the examined glass-aluminum panels. In frame-support glass structures, such as curtain walls, where glass plates are mounted onto a metal framework, the composite behavior between glass and the supporting aluminum elements is usually a problem. It has been showed that an application of elastomer gaskets decreases the stress concentration at the interface between aluminum and glass while does not significantly change the working scheme of the profile. Based on the proposed models, the failure mechanism for wider set of geometrical configurations can be analyzed.

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Experimental and numerical study on fretting wear and fatigue of full-scale railway axles

Railway Engineering Science ◽

10.1007/s40534-020-00224-9 ◽

2020 ◽

Vol 28 (4) ◽

pp. 365-381

Author(s):

Lang Zou ◽

Dongfang Zeng ◽

Yabo Li ◽

Kai Yang ◽

Liantao Lu ◽

...

Keyword(s):

Fatigue Crack ◽

Stress Concentration ◽

Crack Initiation ◽

Numerical Study ◽

Equivalent Stress ◽

Fatigue Crack Initiation ◽

Fretting Fatigue ◽

Full Scale ◽

Fretting Wear ◽

Stress Intensity Factor Range

AbstractThis study investigated the fretting wear and fatigue of full-scale railway axles. Fatigue tests were conducted on full-scale railway axles, and the fretting wear and fretting fatigue in the fretted zone of the railway axles were analysed. Three-dimensional finite element models were established based on the experimental results. Then, multi-axial fatigue parameters and a linear elastic fracture mechanics-based approach were used to investigate the fretting fatigue crack initiation and propagation, respectively, in which the role of the fretting wear was taken into account. The experimental and simulated results showed that the fretted zone could be divided into zones I–III according to the surface damage morphologies. Fretting wear alleviated the stress concentration near the wheel seat edge and resulted in a new stress concentration near the worn/unworn boundary in zone II, which greatly promoted the fretting crack initiation at the inner side of the fretted zone. Meanwhile, the stress concentration also increased the equivalent stress intensity factor range ΔKeq below the mating surface, and thus promoted the propagation of fretting fatigue crack. Based on these findings, the effect of the stress redistribution resulting from fretting wear is suggested to be taken into account when evaluating the fretting fatigue in railway axles.

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