Experimental Fatigue Evaluation of Aluminum Brazed Plate Fin Heat Exchangers

2013 ◽  
Author(s):  
Reinhold Hölzl ◽  
Rainer Flüggen
Keyword(s):  
Experimental Investigation ◽  
Finite Element ◽  
Heat Exchangers ◽  
Large Scale ◽  
Load Cycle ◽  
Process Industry ◽  
Strong Basis ◽  
Fatigue Design ◽  
Fatigue Evaluation ◽  
Good Agreement

For the verification of a finite element based calculation procedure for the strength and fatigue design of aluminum brazed Plate Fin Heat Exchangers (PFHE) an extensive experimental investigation program was planned and executed. In the first step high temperature loadings as single events were applied to the PFHEs to recognize, whether damage (a leak) can be produced by a severe single loading. After various tests on different geometries the investigations were enlarged to thermal cycling tests on small PFHEs until leaks were detected. The tests were executed with three blocks in parallel to cover a statistical influence and the tests were repeated with three new blocks under identical conditions. All six blocks gave nearly the same number of load cycles until first detection of leaks. In addition three blocks of the same geometry were loaded with lower thermal stress, giving higher load cycle numbers until a leak occurred. The experimentally determined cycle numbers were compared to calculated cycle numbers out of the finite element modeling and showed very good agreement. Those tests and comparisons are a strong basis for fatigue and lifetime considerations on large scale PFHEs in the process industry.

The vibration of ring-stiffened prolate domes under external water pressure

2003 ◽  
Vol 217 (2) ◽  
pp. 173-185
Author(s):  
C T F Ross ◽  
A P F Little ◽  
L Chasapides ◽  
J Banks ◽  
D Attanasio
Keyword(s):  
Finite Element Method ◽  
Experimental Investigation ◽  
Finite Element ◽  
Water Pressure ◽  
The Finite Element Method ◽  
Resonant Frequencies ◽  
External Water Pressure ◽  
External Water ◽  
Theory And Experiment ◽  
Good Agreement

The paper presents a theoretical and an experimental investigation into the free vibration of three ring-stiffened prolate domes in air and under external water pressure. The theoretical investigation was via the finite element method where a solid fluid mesh was used to model the water surrounding each dome. Good agreement was found between theory and experiment. Both the theory and the experiment found that, as the external water pressure was increased, the resonant frequencies decreased.

FINITE ELEMENT MODELING OF STEEL-CONCRETE COMPOSITE BEAMS STRENGTHENED WITH PRESTRESSED CFRP PLATE

2012 ◽  
Vol 12 (01) ◽  
pp. 23-51 ◽  
Author(s):  
R. EL-HACHA ◽  
P. ZANGENEH ◽  
H. Y. OMRAN
Keyword(s):  
Finite Element ◽  
Finite Element Modeling ◽  
Parametric Study ◽  
Large Scale ◽  
Composite Beams ◽  
Experimental Results ◽  
Fe Model ◽  
Element Modeling ◽  
Cfrp Plate ◽  
Good Agreement

Results from finite element modeling (FEM) of large-scale steel-concrete composite beams strengthened in flexure with prestressed carbon fiber-reinforced polymer (CFRP) plate were validated with experimental results and presented in this paper. The effect of varying the level of prestressing as percentage of the ultimate tensile strength of the CFRP plate was investigated. Comparison was carried out in terms of overall load-deflection behavior, strain profile along the length of the CFRP plate, and strain distribution across the depth of the beam at mid-span section. Very good agreement was observed between the finite element (FE) and the experimental results. The validated FE models were used to perform a comprehensive parametric study to investigate the changes in the behavior through wider range of prestressing levels and then, determine the optimum prestressing level that maintain the unstrengthened beams' original ductility (or energy absorption). An iterative analytical model was also developed, validated with both the FE model and the experimental results, and showed good agreement. A parametric study was carried out to investigate the effect of changing the yield strength of the steel and the concrete compressive strength on the moment of resistance of the section and the strain in the CFRP plate at ultimate.

Finite element studies of reinforced concrete slab - edge column connections with openings

2007 ◽  
Vol 34 (8) ◽  
pp. 952-965 ◽  
Author(s):  
Hong Guan ◽  
Maria Anna Polak
Keyword(s):  
Finite Element ◽  
Reinforced Concrete ◽  
Large Scale ◽  
Numerical Study ◽  
Concrete Slab ◽  
Reinforced Concrete Slab ◽  
Element Analysis ◽  
Numerical Studies ◽  
Experimental Findings ◽  
Good Agreement

An extended nonlinear layered finite element method (LFEM) is used to investigate the influence of openings and shear stud reinforcement (SSR) on the behaviour of reinforced concrete slab – edge column connections. In all, ten large-scale slab – edge column connections tested previously are analyzed. The laboratory test variables were the size and location of the openings in the vicinity of an edge column and the existence of SSR. The numerical results of the load–deflection response, the ultimate strength, and the crack patterns are compared with the experimental findings and good agreement is achieved. A numerical study on two connections is also carried out to determine the influence of the locations of opening in slab – edge column connections with SSR. Discussion on code provisions for slabs with openings is provided. The comparative and numerical studies confirm the accuracy, reliability, and effectiveness of the LFEM in the analysis of slab – edge column connections with both openings and SSR.Key words:slab–column connection, punching shear, opening, shear stud reinforcement, finite element analysis.

Experimental investigation and modelling of light scattering in a-Si:H solar cells deposited on glass/ZnO:Al substrates

2002 ◽  
Vol 715 ◽  
Author(s):  
J. Krc ◽  
M. Zeman ◽  
O. Kluth ◽  
F. Smole ◽  
M. Topic
Keyword(s):  
Surface Roughness ◽  
Experimental Investigation ◽  
Solar Cells ◽  
Angular Distribution ◽  
Light Scattering ◽  
Optical Model ◽  
Distribution Functions ◽  
Interface Roughness ◽  
Scattering Parameters ◽  
Good Agreement

AbstractThe descriptive scattering parameters, haze and angular distribution functions of textured ZnO:Al transparent conductive oxides with different surface roughness are measured. An approach to determine the scattering parameters of all internal interfaces in p-i-n a-Si:H solar cells deposited on the glass/ZnO:Al substrates is presented. Using the determined scattering parameters as the input parameters of the optical model, a good agreement between the measured and simulated quantum efficiencies of the p-i-n a-Si:H solar cells with different interface roughness is achieved.

Analysis of the Contact Deformation of Tread Blocks

1992 ◽  
Vol 20 (4) ◽  
pp. 230-253 ◽  
Author(s):  
T. Akasaka ◽  
K. Kabe ◽  
M. Koishi ◽  
M. Kuwashima
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Deformation Behavior ◽  
Contact Deformation ◽  
The Finite Element Method ◽  
The Road ◽  
Loss Of Contact ◽  
Tread Rubber ◽  
Good Agreement ◽  
Rubber Block

Abstract The deformation behavior of a tire in contact with the roadway is complicated, in particular, under the traction and braking conditions. A tread rubber block in contact with the road undergoes compression and shearing forces. These forces may cause the loss of contact at the edges of the block. Theoretical analysis based on the energy method is presented on the contact deformation of a tread rubber block subjected to compressive and shearing forces. Experimental work and numerical calculation by means of the finite element method are conducted to verify the predicted results. Good agreement is obtained among these analytical, numerical, and experimental results.

scholarly journals Stator Non-Uniform Radial Ventilation Design Methodology for a 15 MW Turbo-Synchronous Generator Based on Single Ventilation Duct Subsystem

Energies ◽  
2021 ◽  
Vol 14 (10) ◽  
pp. 2760
Author(s):  
Ruiye Li ◽  
Peng Cheng ◽  
Hai Lan ◽  
Weili Li ◽  
David Gerada ◽  
...  
Keyword(s):  
Finite Element ◽  
Temperature Distribution ◽  
Design Methodology ◽  
Large Scale ◽  
Synchronous Generator ◽  
Axial Direction ◽  
Scale Model ◽  
Element Analysis ◽  
Axial Temperature ◽  
Ventilation Duct

Within large turboalternators, the excessive local temperatures and spatially distributed temperature differences can accelerate the deterioration of electrical insulation as well as lead to deformation of components, which may cause major machine malfunctions. In order to homogenise the stator axial temperature distribution whilst reducing the maximum stator temperature, this paper presents a novel non-uniform radial ventilation ducts design methodology. To reduce the huge computational costs resulting from the large-scale model, the stator is decomposed into several single ventilation duct subsystems (SVDSs) along the axial direction, with each SVDS connected in series with the medium of the air gap flow rate. The calculation of electromagnetic and thermal performances within SVDS are completed by finite element method (FEM) and computational fluid dynamics (CFD), respectively. To improve the optimization efficiency, the radial basis function neural network (RBFNN) model is employed to approximate the finite element analysis, while the novel isometric sampling method (ISM) is designed to trade off the cost and accuracy of the process. It is found that the proposed methodology can provide optimal design schemes of SVDS with uniform axial temperature distribution, and the needed computation cost is markedly reduced. Finally, results based on a 15 MW turboalternator show that the peak temperature can be reduced by 7.3 ∘C (6.4%). The proposed methodology can be applied for the design and optimisation of electromagnetic-thermal coupling of other electrical machines with long axial dimensions.

Sign in / Sign up

Export Citation Format

Share Document