scholarly journals Support of Dynamic Measurements Through Similitude Formulations

2021 ◽  
Author(s):  
A. Casaburo ◽  
G. Petrone ◽  
V. Meruane ◽  
F. Franco ◽  
S. De Rosa
Keyword(s):  
Experimental Testing ◽  
Image Correlation ◽  
Scale Model ◽  
Experimental Measurements ◽  
Dynamic Measurements ◽  
Scaled Model ◽  
Asymptotic Models ◽  
Similitude Theory ◽  
Extract Information

AbstractUp to now, similitude methods have been used in order to overcome the typical drawbacks of experimental testing and numerical simulations by reconstructing the full-scale model behavior from that of the scaled model. The novelty of this work is the application of similitude theory not as a tool for predicting the prototype dynamic response, but for supporting, and eventually validating, experimental measurements polluted by noise. Two Aluminium Foam Sandwich (AFS) plates are analyzed with Digital Image Correlation (DIC) cameras. First, an algorithm for blind source separation problems is used to extract information about the excitation; then, SAMSARA (Similitude and Asymptotic Models for Structural-Acoustic Research Applications) similitude method is applied to both the force spectra and velocity responses of prototype and model. The reconstruction of force and velocity curves demonstrates that the similitude results are coherent with the quality of the experimental measurements: when the spatial pattern in resonance is recognizable, then the curves overlap. Instead, when the displacement field of just one model is not well identified, the reconstruction exhibits discrepancies. Therefore, similitude methods reveal to be an interesting tool for understanding if a set of measurements is reliable or not and their application should not be underestimated, especially in the light of the expanding range of approaches which can extract important information from noisy observations.

EXPERIMENTAL AND NUMERICAL VALIDATION OF FLEXURAL BEHAVIOUR OF MULTI-SCALE PREFABRICATED INDUSTRIALISED BUILDING SYSTEM (IBS) SUB-FRAME

2017 ◽  
Vol 79 (5) ◽  
Author(s):  
Jing-Ying Wong ◽  
Abdul Kadir Marsono ◽  
Chun-Chieh Yip
Keyword(s):  
Scale Model ◽  
Flexural Test ◽  
Scaled Model ◽  
Element Analysis ◽  
Vertical Loading ◽  
Concrete Crack ◽  
Pi Theorem ◽  
Set Up ◽  
Displacement Transducers ◽  
Similitude Theory

The paper describes the approach to develop the 1/5 scaled physical model and its applicability is validated against full scale model. Non-dimensional modelling methods using Buckingham Pi Theorem and Similitude Theory are explained and material properties for concrete, reinforcement, steel links, and beam-column connections are provided. The comparison between the results of experimental flexural test and Non-Linear Finite Element Analysis (NLFEA) of 1/5 scaled model and prototype of prefabricated IBS are discussed and presented. This paper is to verify the procedures and results of flexural test for 1/5 scaled model of prefabricated IBS in comparison to the prototype. The IBS components were set-up and tested under two-points monotonic vertical loading in Universiti Teknologi Malaysia Structure Laboratory. Three Linear Variable Displacement Transducers (LVDTs) and two strain gauges were instrumented in the small-scaled model to record deflections and strains. Both small-scaled model and prototype were analysed by Abaqus FEA software. Elastic range for both small scaled model and prototype are determined by scaled factor of 5.0, and proven to be accurate by both experimental test and NLFEA with ultimate capacity of 13 kN load and 10.9 mm vertical deflection. Since the similitude theory only applicable until elastic limit, hence the structural performance in nonlinear state is evaluated in concrete crack patterns and beam-column connection deformations are presented graphically in this paper. Load-displacement with maximum 12.9 mm deflection, 35.64 N/mm2 ultimate crushing stresses at concrete and beam-column connection with minimum yield strength of 222.6 N/mm2 are presented. This paper concluded that the procedures and results of flexural test for 1/5 scaled model of prefabricated IBS is valid in comparison to the prototype. 

Validation of mathematical model of electrothermal calculation of DC catenary on the basis of scale model

2018 ◽  
Vol 77 (4) ◽  
pp. 222-229 ◽  
Author(s):  
A. V. Paranin ◽  
A. B. Batrashov
Keyword(s):  
Mathematical Model ◽  
Operating Conditions ◽  
Scale Model ◽  
Contact Network ◽  
Scaled Model ◽  
Cross Sectional ◽  
Current Collection ◽  
Topological Features ◽  
Study Results ◽  
Real Physical Process

The article compares the results of calculation of the finite element simulation of current and temperature distribution in the scale model of the DC catenary with the data of laboratory tests. Researches were carried on various versions of the structural design of catenary model, reflecting the topological features of the wire connection, characteristic of the DC contact network. The proportions of the cross-sectional area of the scaled model wires are comparable to each other with the corresponding values for real DC catenary. The article deals with the operating conditions of the catenary model in the modes of transit and current collection. When studying the operation of the scale catenary model in the transit mode, the effect of the structural elements on the current distribution and heating of the wires was obtained. Within the framework of the scale model, theoretical assumptions about the current overload of the supporting cable near the middle anchoring have been confirmed. In the current collection mode, the experimental dependences of the current in the transverse wires of the scale model are obtained from the coordinate of the current collection point. Using the model it was experimentally confirmed that in the section of the contact wire with local wear, not only the temperature rise occurs but also the current redistribution due to the smaller cross section. Thus, the current share in other longitudinal wires of the scale model increases and their temperature rises. Scale and mathematical models are constructed with allowance for laboratory clamps and supporting elements that participate in the removal of heat from the investigated wires. Obtained study results of the scale model allow to draw a conclusion about the adequacy of the mathematical model and its correspondence to the real physical process. These conclusions indicate the possibility of applying mathematical model for calculating real catenary, taking into account the uneven contact wear wire and the armature of the contact network.

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.

Optimal Parameter Design of Solder Residue in Flip Chip Process by Using Taguchi Method

2010 ◽  
Vol 443 ◽  
pp. 543-548
Author(s):  
Jian Long Kuo ◽  
Kai Lun Chao ◽  
Chun Cheng Kuo
Keyword(s):  
Taguchi Method ◽  
Product Quality ◽  
Manufacturing Process ◽  
Flip Chip ◽  
Optimal Parameter ◽  
Experimental Testing ◽  
Signal To Noise Ratio ◽  
Optimal Solution ◽  
Passive Component

Because the solder residue was found in the manufacturing process which greatly affected the product quality, the purpose of this paper was to make the product quality improved and to find an optimal solution for process parameters in the flip chip process. The experimental testing was based on SMT manufacturing process. The amount and size of solder left on passive component in the process of manufacturing were considered as the quality traits. Since too many solders left on the passive component side during flux cleaning process, it was possible that the balling would be flowed into the chip, which caused the bump short in the chip and affected the quality of the product. In this paper, orthogonal array by using Taguchi method is adopted as the effective experimental method with the least experimental runs. Also, based on the quality evaluation of signal-to-noise ratio, the ANOVA is used to evaluate the effects of quality target according to the experimental results. The results reveal that the optimization in the process is confirmed. Therefore, this study can effectively improve the solder residue in semiconductor manufacturing process.

Experimental testing of open pit dump trucks in operating conditions

2020 ◽  
pp. 530-542
Author(s):  
A. G. Zhuravlev ◽  
M. V. Isakov
Keyword(s):  
Power Plants ◽  
Experimental Testing ◽  
Operating Conditions ◽  
Open Pit ◽  
Dump Truck ◽  
Experimental Measurements ◽  
Complex Data ◽  
Special Unit ◽  
Operating Modes ◽  
Dump Trucks

The high importance of optimizing the operation of quarry transport is confirmed by the leading share of its costs in the total cost of mining. The current direction of optimization is the development and implementation of digital technologies for processing complex data on the parameters of transport vehicles. The solution of the above issues should be based on the results of scientific research on the collection and processing of information. Developed a set of techniques to perform experimental measurements of working parameters of mining dump trucks as part of a special unit experiments, and long monitoring measurements. A set of equipment for performing experimental measurements, as well as its installation on a dump truck is presented. The data of experimental measurements and a methodical approach to their analysis are presented. In particular, it shows the identification of operating modes of the power plant and the construction of the load diagram, the identification of elements of the transport cycle, etc. The approach to substantiation of innovative designs of power plants adapted to the conditions of a particular quarry is shown on the example of calculated schedules of energy consumption and reserve of recovery of braking energy. The proposed hardware-methodical complex is a research model for the development of methods for automated data collection and processing in the formation of elements of digital mining production.

A Polytomous Rasch Analysis of the English Version of Health-Related Quality of Life for Drug Abusers Test

2015 ◽  
Vol 18 ◽  
Author(s):  
Oscar M. Lozano ◽  
Antonio J. Rojas Tejada ◽  
Katia Foresti ◽  
Carlos Zubaran
Keyword(s):  
Quality Of Life ◽  
Psychometric Properties ◽  
Rasch Model ◽  
Scale Model ◽  
Drug Abusers ◽  
Health Related Quality ◽  
English Version ◽  
Related Quality ◽  
Health Related

AbstractThe specific aim of this study was to analyze the psychometric properties of the English version of the Health-Related Quality of Life for Drug Abusers Test (HRQoLDA Test) applying the Rasch model, and emphasizing fit between empirical data and theoretical Rasch model assumptions; item(s) category probability curve; and precision in terms of information function. In this study, the authors present the results of the translation and adaptation of the original Spanish version to English, as applied to a sample of substance users in Australia. The authors evaluated 121 adults recruited from inpatient and outpatient treatment facilities in Sydney, Australia. The Rating Scale Model was used in the psychometric analysis of the English version of the HRQoLDA Test. The items and persons revealed a fit between the reported data and the model. It was also demonstrated that respondents did not discriminate among the five response categories, which led to a reduction to three response categories. The adaptation of the TECVASP to the English language, renamed the HRQoLDA test, as developed with an Australian sample revealed adequate psychometric properties.

scholarly journals NUMERICAL PREDICTIONS AND MECHANICAL TESTING OF BRAIDED COMPOSITE STRUCTURES UTILISING DIGITAL IMAGE CORRELATION

2016 ◽  
Vol 7 ◽  
pp. 43
Author(s):  
Emil Pitz ◽  
Matei-Constantin Miron ◽  
Imre Kállai ◽  
Zoltán Major
Keyword(s):  
Numerical Model ◽  
Digital Image Correlation ◽  
Digital Image ◽  
Composite Structures ◽  
Experimental Testing ◽  
Single Layer ◽  
Failure Criteria ◽  
Image Correlation ◽  
Braided Composites ◽  
Numerical Predictions

The current paper is describing the implementation of a multiscale numerical model for prediction of stiffness and strength in braided composites. The model is validated by experimental testing of single-layer braided tubes under torsional loading utilising digital image correlation (DIC). For the numerical model the entire braided structure is modelled at yarn detail level, taking into account the yarn behaviour as well as individual yarn-to-yarn interactions by using cohesive contact definitions. By means of Hashin’s failure criteria and cohesive contact damage, failure of the yarns and failure of the yarn-to-yarn interface is being accounted for. Thereby the material failure behaviour can be predicted. For validation of the model, torsion tests of biaxially braided single-layer composite tubes were performed. The strain distribution at the specimen surface was studied using the DIC system ARAMIS in 3D mode.

scholarly journals Operational capability assessment for the hyperspectral sensor NA-GS using statistical and simulation modeling

2019 ◽  
pp. 74-83
Author(s):  
S. A. Zotov ◽  
E. V. Dmitriev ◽  
S. Yu. Shibanov ◽  
V. V. Kozoderov ◽  
S. A. Donskoy
Keyword(s):  
Simulation Modeling ◽  
Experimental Testing ◽  
Space Station ◽  
Quality Criteria ◽  
Statistical Simulation ◽  
Hyperspectral Images ◽  
Scientific Instrument ◽  
Operational Capabilities ◽  
Monitoring And Forecasting

Within the framework of the program on Earth remote sensing from space, the hyperspectral camera NA-GS (scientific instrument "Hyperspectrometer") produced by NPO Lepton (Zelenograd, Moscow) will be installed on the Russian segment of the International Space Station (ISS) for experimental testing of the ground-space system for monitoring and forecasting natural and man-made disasters. The practical use of this system is associated with solving certain problems of thematic processing hyperspectral images that must meet certain quality criteria. In this paper, we propose a technique for determining the operational capabilities of NA-GS instrument based on statistical simulation modeling (SSM) data. The concept of the proposed SSM includes the ability to perform model experiments for a test polygon of complex shape, simulation of hyperspectral imaging of selected parts of the polygon with a specified accuracy, and taking into account the clouds and the zenith angle of the sun. The influence of external observation conditions on the quality of hyperspectral images is considered. Numerical experiments were carried out for selected test areas. The analysis of the results obtained confirms reliability of the proposed technique.

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