scholarly journals Compact Heat Exchanger Semi-Circular Header Burst Pressure and Strain Validation

2019 ◽  
Author(s):  
Blake W. Lance ◽  
Matthew D. Carlson
Keyword(s):  
Accuracy Assessment ◽  
Two Dimensions ◽  
Experimental Results ◽  
Image Correlation ◽  
Burst Pressure ◽  
Element Analysis ◽  
Simulation Accuracy ◽  
The Rich ◽  
Rich Data ◽  
Deformation Measurements

Abstract Compact heat exchangers for supercritical CO2 (sCO2) service are often designed with external, semi-circular headers. Their design is governed by the ASME Boiler & Pressure Vessel Code (BPVC) whose equations were typically derived by following Castigliano’s Theorems. However, there are no known validation experiments to support their claims of pressure rating or burst pressure predictions nor is there much information about how and where failures occur. This work includes high pressure bursting of three semi-circular header prototypes for the validation of three aspects: (1) burst pressure predictions from the BPVC, (2) strain predictions from Finite Element Analysis (FEA), and (3) deformation from FEA. The header prototypes were designed with geometry and weld specifications from the BPVC Section VIII Division 1, a design pressure typical of sCO2 service of 3,900 psi (26.9 MPa), and were built with 316 SS. Repeating the test in triplicate allows for greater confidence in the experimental results and enables data averaging. Burst pressure predictions are compared with experimental results for accuracy assessment. The prototypes are analyzed to understand their failure mechanism and locations. Experimental strain and deformation measurements were obtained optically with Digital Image Correlation (DIC). This technique allows strain to be measured in two dimensions and even allows for deformation measurements, all without contacting the prototype. Eight cameras are used for full coverage of both headers on the prototypes. The rich data from this technique are an excellent validation source for FEA strain and deformation predictions. Experimental data and simulation predictions are compared to assess simulation accuracy.

A Fuzzy-Based Recommender System for Electronic Products Selection using Users' Requirements and Other Users' Opinion

2015 ◽  
Vol 4 (1) ◽  
pp. 76-87 ◽  
Author(s):  
Bolanle Adefowoke Ojokoh ◽  
Olatunji Mumini Omisore ◽  
Oluwarotimi Williams Samuel ◽  
Temidayo Otunniyi
Keyword(s):  
Fuzzy Logic ◽  
Recommender System ◽  
Experimental Results ◽  
Electronic Products ◽  
Hybrid Recommender System ◽  
The Rich ◽  
Rich Data ◽  
Hybrid Recommender ◽  
The Web ◽  
Experience Difficulty

E-Commerce has become very popular these days because it is convenient, reliable, and fast to use. In spite of these advantages, online buyers often experience difficulty in searching for products on the web, while online businesses are often overwhelmed by the rich data they have collected and find it difficult to promote products appropriate to specific customers. This paper proposes a hybrid recommender system that uses fuzzy logic to intelligently mine the requirements of each specific customer, together with some previous users' opinions about the product, to recommend a list of optimal products to meet users' needs. Experimental results of the proposed system with different brands of laptops prove its effectiveness.

scholarly journals Preliminary Experimental and Numerical Study of Metal Element with Notches Reinforced by Composite Materials

2021 ◽  
Vol 5 (5) ◽  
pp. 134
Author(s):  
Paweł J. Romanowicz ◽  
Bogdan Szybiński ◽  
Mateusz Wygoda
Keyword(s):  
Digital Image Correlation ◽  
Digital Image ◽  
Numerical Study ◽  
Correlation Method ◽  
Industrial Applications ◽  
Experimental Results ◽  
Image Correlation ◽  
Stress Concentrations ◽  
Element Analysis ◽  
Wide Range

The presented study is related to the application of the composite overlays used in order to decrease the effect of the stress concentrations around the cut-outs in structural metal elements. The proposed approach with the application of the digital image correlation extends the recently presented studies. Such structural elements with openings of various shapes have been accommodated for a wide range of industrial applications. These structures exhibit certain stress concentrations which decrease their durability and strength. To restore their strength, various reinforcing overlays can be used. In the present paper, the flat panel structure without and with the composite overlays made of HEXCEL TVR 380 M12/26%/R-glass/epoxy is under the experimental and the numerical study. Particular attention is paid to the investigation of the samples with the rectangular holes, which for smooth rounded corners offer a higher durability than the samples with the circular hole of the same size. The experimental results are obtained for the bare element and are reinforced with composite overlay samples. The experimental results are obtained with the use of the Digital Image Correlation method, while the numerical results are the product of the Finite Element Analysis. In the numerical analysis, the study of the shape, size and fiber orientation in applied overlays is done. The reduction of the stress concentration observed in opening notches has confirmed the effectiveness of the overlay application. In the investigated example, the application of the square composite overlay increased the structure strength even by 25%.

Evaluation of Strength of Pipe With Metal-Loss due to CUI by FFS and FEA Which Considered the Fracture Ductility

2018 ◽  
Author(s):  
Atsushi Yamaguchi ◽  
Nobuyuki Yoshida
Keyword(s):  
Ductile Fracture ◽  
Stress Condition ◽  
Experimental Results ◽  
Burst Pressure ◽  
Metal Loss ◽  
Multiaxial Stress ◽  
Element Analysis ◽  
Domestic Industry ◽  
Corrosion Under Insulation

Corrosion under insulation (CUI) is an aging degradation issue in long-term service vessels and pipes made of carbon steel and low-alloy steel. One of the problems in managing CUI is an equivocal evaluation technique of thinning detected by inspection. A replacement period with more accuracy can be evaluated more appropriately by performing fitness-for-service (FFS) assessment in this equipment. It is important to verify the validity of the FFS assessment using actually corroded pipes in order to promote the spread of FFS assessment in the domestic industry. In the present paper, pipes with complicated metal-loss due to CUI that were used in a chemical plant are burst in burst tests. An estimated burst pressure, which is calculated based on the assessment of metal-loss and through finite element analysis (FEA) based on FFS assessment, is compared with experimentally obtained burst pressures in order to validate the integrity evaluation. The burst pressure is then estimated by FEA, in which the ductile fracture under the multiaxial stress condition is considered. The burst pressure estimated by FFS approximately matched the burst pressure obtained based on experimental results. Fitness-for-service is sufficiently valid for investigating the remaining strength or burst pressure of corroded pipe. In addition, the burst pressure estimated by FEA that considered the ductile fracture under the multiaxial stress condition agreed with the experimental results and is valid so long as the remaining strength factor (RSF) is less than 0.6.

Local Strain Measurement in Tensile Test for an Optimized Characterization of Packaging Steel for Finite Element Analysis

2021 ◽  
Vol 883 ◽  
pp. 309-316
Author(s):  
Fabian Knieps ◽  
Manuel Köhl ◽  
Marion Merklein
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Tensile Test ◽  
Flow Curve ◽  
Material Selection ◽  
Image Correlation ◽  
Temper Rolling ◽  
Element Analysis ◽  
Simulation Accuracy

The continuous development of packaging steels for thickness reduction processes requires an advanced process design. This process is increasingly supported by finite element analysis to simplify tool construction and material selection purposes. Therefore, the fundamental basis is always the precise material characterization of packaging steel commonly based on tensile tests to determine flow curve and Lankford coefficients. However, due to strong temper rolling and the occurrence of slip bands, most packaging steels just show little elongation in tensile test. Therefore, a method of Paul et al. to determine the flow curve with digital image correlation (DIC) methods in the necking zone was applied in this work to meet the requirements of packaging steel. For the use of anisotropic yield functions, it is necessary to determine Lankford coefficients. Thus, a new method is proposed to measure Lankford coefficients locally with a DIC system in tensile test, also in case that no homogenous forming condition is reached. With the presented approaches the packaging steel TH415 was characterized. In order to validate the developed methods, a demonstrator was simulated with anisotropic yield function Yld2000-2d . The comparison between simulation and experiment showed clear improvements in simulation accuracy when using the newly presented methods for packaging steel.

Deformation Measurements and Material Property Estimation of Mouse Carotid Artery Using a Microstructure-Based Constitutive Model

2010 ◽  
Vol 132 (12) ◽  
Author(s):  
Jinfeng Ning ◽  
Shaowen Xu ◽  
Ying Wang ◽  
Susan M. Lessner ◽  
Michael A. Sutton ◽  
...  
Keyword(s):  
Carotid Artery ◽  
Constitutive Model ◽  
Vascular Tissue ◽  
Three Dimensional ◽  
Tensile Loading ◽  
Surface Strain ◽  
Image Correlation ◽  
Element Analysis ◽  
Constitutive Parameters ◽  
Deformation Measurements

A series of pressurization and tensile loading experiments on mouse carotid arteries is performed with deformation measurements acquired during each experiment using three-dimensional digital image correlation. Using a combination of finite element analysis and a microstructure-based constitutive model to describe the response of biological tissue, the measured surface strains during pressurization, and the average axial strains during tensile loading, an inverse procedure is used to identify the optimal constitutive parameters for the mouse carotid artery. The results demonstrate that surface strain measurements can be combined with computational methods to identify material properties in a vascular tissue. Additional computational studies using the optimal material parameters for the mouse carotid artery are discussed with emphasis on the significance of the qualitative trends observed.

scholarly journals Influence of Circumferential Flaw Length on Internal Burst Pressure of a Wall-Thinned Pipe

2012 ◽  
Author(s):  
Masataka Tsuji ◽  
Toshiyuki Meshii
Keyword(s):  
Finite Element Analysis ◽  
Fracture Mode ◽  
Experimental Results ◽  
The Other ◽  
Burst Pressure ◽  
Test Results ◽  
Element Analysis ◽  
Burst Test ◽  
Axial Crack ◽  
Planar Flaw

The effect of the circumferential angle of a flaw θ on the internal burst pressure pf of pipes with artificial wall-thinned flaws is examined. When evaluating pf of wall-thinned straight pipes, the effect of θ has been conventionally not regarded as important. Therefore, a burst pressure equation for an axial crack inside a cylinder (Fig. 1, left), such as Kiefner’s equation [1] is widely used [2], [3]. However, it should be noted that there exist the following implicit assumptions when applying the equation for planar flaws to non-planar flaws. 1) The fracture mode of a non-planar flaw under consideration is identical with that of the crack. 2) The effect of θ, which is not considered for an axial crack on pf, is small or negligible. However, from the systematic burst test results of carbon pipes with artificial wall-thinned flaws, Meshii [4] showed that these implicit assumptions may not be correct. On the other hand, the significance of the effect of the fracture mode on pf and the condition for θ to affect pf are not clear. Therefore, in this paper, Meshii’s experimental results are evaluated in farther detail. The purpose of the evaluation was set to clarify the effect of θ on pf. Specifically, the significance of flaw configuration (axial length δz and wall-thinning ratio t1/t) was studied in relation to θ and pf. In addition, a simulation of the effect by a Finite Element Analysis (FEA) was attempted. From the experimental results, θ tended to affect pf in cases with large δz, and t1/t also was correlated to a decrease in pf with the increase of θ. These tendencies were successfully simulated by the elastic-plastic FEA. This effect means the burst pressure predicted for a crack with identical ligament thickness decreases with the increase of θ, so that the effect by θ on pf should not be ignored.

Tire Cornering Simulation Using an Explicit Finite Element Analysis Code

1998 ◽  
Vol 26 (2) ◽  
pp. 109-119 ◽  
Author(s):  
M. Koishi ◽  
K. Kabe ◽  
M. Shiratori
Keyword(s):  
Finite Element Method ◽  
Finite Element Analysis ◽  
Finite Element ◽  
Test System ◽  
Experimental Results ◽  
The Finite Element Method ◽  
Element Analysis ◽  
Explicit Finite Element ◽  
Explicit Finite Element Analysis ◽  
Element Method

Abstract The finite element method has been used widely in tire engineering. Most tire simulations using the finite element method are static analyses, because tires are very complex nonlinear structures. Recently, transient phenomena have been studied with explicit finite element analysis codes. In this paper, the authors demonstrate the feasibility of tire cornering simulation using an explicit finite element code, PAM-SHOCK. First, we propose the cornering simulation using the explicit finite element analysis code. To demonstrate the efficiency of the proposed simulation, computed cornering forces for a 175SR14 tire are compared with experimental results from an MTS Flat-Trac Tire Test System. The computed cornering forces agree well with experimental results. After that, parametric studies are conducted by using the proposed simulation.

scholarly journals Design of a Unique Device for Residual Stresses Quantification by the Drilling Method Combining the PhotoStress and Digital Image Correlation

Materials ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 314
Author(s):  
Miroslav Pástor ◽  
Martin Hagara ◽  
Ivan Virgala ◽  
Adam Kaľavský ◽  
Alžbeta Sapietová ◽  
...  
Keyword(s):  
Digital Image Correlation ◽  
Digital Image ◽  
Experimental Testing ◽  
Digital Processing ◽  
Image Correlation ◽  
Optical Systems ◽  
Hole Drilling ◽  
Element Analysis ◽  
Thin Specimen ◽  
Comparison Of The Results

This paper presents a uniquely designed device combining the hole-drilling technique with two optical systems based on the PhotoStress and digital image correlation (DIC) method, where the digital image correlation system moves with the cutting tool. The authors aimed to verify whether the accuracy of the drilled hole according to ASTM E837-13a standard and the positioning accuracy of the device were sufficient to achieve accurate results. The experimental testing was performed on a thin specimen made from strain sensitive coating PS-1D, which allowed comparison of the results obtained by both methods. Although application of the PhotoStress method allows analysis of the strains at the edge of the cut hole, it requires a lot of experimenter’s practical skills to assess the results correctly. On the other hand, the DIC method allows digital processing of the measured data. However, the problem is not only to determine the data at the edge of the hole, the results also significantly depend on the smoothing levels used. The quantitative comparison of the results obtained was performed using finite element analysis.

scholarly journals Is contact angle a cause or an effect? – A cautionary tale

2020 ◽  
Vol 146 ◽  
pp. 03004
Author(s):  
Douglas Ruth
Keyword(s):  
Contact Angle ◽  
Solid Surface ◽  
Contact Angles ◽  
Two Dimensions ◽  
Experimental Results ◽  
Flow In Porous Media ◽  
Two Dimensional ◽  
Wide Range ◽  
Fluid Drop ◽  
Surrounding Fluid

The most influential parameter on the behavior of two-component flow in porous media is “wettability”. When wettability is being characterized, the most frequently used parameter is the “contact angle”. When a fluid-drop is placed on a solid surface, in the presence of a second, surrounding fluid, the fluid-fluid surface contacts the solid-surface at an angle that is typically measured through the fluid-drop. If this angle is less than 90°, the fluid in the drop is said to “wet” the surface. If this angle is greater than 90°, the surrounding fluid is said to “wet” the surface. This definition is universally accepted and appears to be scientifically justifiable, at least for a static situation where the solid surface is horizontal. Recently, this concept has been extended to characterize wettability in non-static situations using high-resolution, two-dimensional digital images of multi-component systems. Using simple thought experiments and published experimental results, many of them decades old, it will be demonstrated that contact angles are not primary parameters – their values depend on many other parameters. Using these arguments, it will be demonstrated that contact angles are not the cause of wettability behavior but the effect of wettability behavior and other parameters. The result of this is that the contact angle cannot be used as a primary indicator of wettability except in very restricted situations. Furthermore, it will be demonstrated that even for the simple case of a capillary interface in a vertical tube, attempting to use simply a two-dimensional image to determine the contact angle can result in a wide range of measured values. This observation is consistent with some published experimental results. It follows that contact angles measured in two-dimensions cannot be trusted to provide accurate values and these values should not be used to characterize the wettability of the system.

Sign in / Sign up

Export Citation Format

Share Document