scholarly journals Measurement of Fracture Parameters for a Mixed-Mode Crack Driven by Stress Waves using Image Correlation Technique and High-Speed Digital Photography

Strain ◽  
2009 ◽  
Vol 45 (2) ◽  
pp. 108-122 ◽  
Author(s):  
M. S. Kirugulige ◽  
H. V. Tippur
Keyword(s):  
Mixed Mode ◽  
High Speed ◽  
Digital Photography ◽  
Stress Waves ◽  
Image Correlation ◽  
Correlation Technique ◽  
Fracture Parameters ◽  
Mixed Mode Crack

The Influence of Facet Size on the Accuracy of Modal Parameters Determined by Digital Image Correlation Technique

2014 ◽  
Vol 611 ◽  
pp. 496-500 ◽  
Author(s):  
Róbert Huňady ◽  
Martin Hagara ◽  
František Šimčák
Keyword(s):  
Digital Image Correlation ◽  
Digital Image ◽  
High Speed ◽  
Image Correlation ◽  
Modal Parameters ◽  
Correlation Technique ◽  
Correlation System ◽  
Correlation Process ◽  
The Impact ◽  
Facet Size

The paper deals with measurements of modal parameters using high-speed digital image correlation and assesses how the size of image elements (facets) influences the accuracy of modal parameters of the analyzed structure. The facet size is an important parameter that significantly affects the correlation process and its results. In the paper the experimental modal analysis of steel circular plate that has been excited by the impact hammer is described. Correlation system Q-450 Dantec Dynamics was used to measure the responses of the analyzed structure.

Stent Expansion in Curved Vessel and Their Interactions: An In Vitro Study

2014 ◽  
Author(s):  
Shijia Zhao ◽  
Shengmao Lin ◽  
Linxia Gu
Keyword(s):  
High Speed ◽  
In Vitro Study ◽  
Image Correlation ◽  
Correlation Technique ◽  
Digital Image Correlation Technique ◽  
Stent Expansion ◽  
Curved Artery ◽  
Induced Changes ◽  
Stenting Procedure

The objective of this work is to characterize the interaction between balloon-expandable stents and curved artery simulants. The deformation at the outer surface of the curved artery simulant was monitored using two high-speed cameras, and the corresponding strain map was obtained with 3-D digital image correlation technique. The anisotropic variations in the arterial mechanics were clearly observed. Results indicated three distinct phases during the stenting procedure, i.e., expansion, recoil and stabilization. The stent expansion dramatically altered the strain field of the curved artery simulant, and larger strain was observed around the center of stent than its two ends. In addition, the change in curvature of the simulant during the implantation of stent was quantified. This work characterized and quantified the interaction between stent and artery simulant in a laboratory setting, which could facilitate the optimization of the stent design for minimizing the stent-induced changes in the mechanical environment of artery.

scholarly journals EXPERIMENTAL AND THEORETICAL RESEARCH ON REINFORCED LIGHTWEIGHT CONCRETE FLEXURAL ELEMENTS / ARMUOTOJO LENGVOJO BETONO LENKIAMŲJŲ ELEMENTŲ EKSPERIMENTINIAI IR TEORINIAI TYRIMAI

2014 ◽  
Vol 6 (5) ◽  
pp. 480-487
Author(s):  
Deividas Rumšys ◽  
Darius Bačinskas ◽  
Edmundas Spudulis ◽  
Eugenijus Gudonis ◽  
Aleksandr Sokolov
Keyword(s):  
High Speed ◽  
Lightweight Concrete ◽  
Image Correlation ◽  
Theoretical Research ◽  
Correlation Technique ◽  
Video Cameras ◽  
Strain Behavior ◽  
Four Point Bending ◽  
Vertical Displacements ◽  
Bending Loading

The paper deals with analysis of structural lightweight concrete. New lightweight concrete mixture made with expanded clay aggregate has been proposed and applied for experimental rein-forced concrete beams. Totally 8 beams with different rein-forcement ratios (0.309%, 0.557%, 0.895% and 1.255%) were tested under short-term four point bending loading. Stress-strain behavior of the beams under considerations has been investigated. Average strains at 4 different levels of pure bend-ing zone and vertical displacements at 12 different points of the beam were measured. During the test, deformations and crack-ing of the pure bending zone were additionally observed using high-speed digital video cameras. The data obtained by cameras were analyzed using digital image correlation technique. Applying the test data bending moments and curvature diagrams were derived for each beam. The obtained relationships were compared with theoretical results calculated using design code methods LST EN and STR. Using the inverse algorithm developed by VGTU, tension reinforced lightweight concrete stress and strain diagrams were obtained, which were adapted to numerical modeling by software ATENA. Moment and curvature diagrams obtained by finite elements program were compared with experimental moment and curvature diagrams. Good agreement between both diagrams has been obtained. Straipsnyje aprašytas naujai sukurtas konstrukcinis lengvasis betonas ir jo panaudojimas eksperimentinių armuotojo lengvojo betono sijų gamybai. Atlikti trumpalaike apkrova veikiamų plieniniais strypais armuotų lengvojo betono sijų eksperimentiniai tyrimai, kuriuose nagrinėtas sijų įtempių ir deformacijų būvis. Laboratorijoje išbandyti 8 lenkiamieji elementai, kurių armavimo procentai: 0,309 %, 0,557 %, 0,895 % ir 1,255 %. Tyrimų metu matuotos vidutinės elemento deformacijos grynojo lenkimo zonoje 4 skirtinguose lygmenyse bei sijų poslinkiai ties atramomis, jėgos pridėjimo vietose ir viduriniame pjūvyje (iš viso 12 matavimo taškų). Bandymo metu grynojo lenkimo zonos deformacijos bei pleišėjimas papildomai stebėti greitaeige vaizdo kamera. Gauti rezultatai panaudoti sudarant eksperimentines lenkimo momentų ir kreivių diagramas, kurios palygintos su teoriškai apskaičiuotomis taikant Lietuvoje galiojančių LST EN ir STR projektavimo normų metodikas. Taikant VGTU sukurtą atvirkštinio uždavinio algoritmą, gautos tempiamo armuotojo lengvojo betono įtempių ir deformacijų diagramos, kurios pritaikytos atliekant skaitinį modeliavimą baigtinių elementų programa ATENA. Gautos momentų ir kreivių diagramos baigtinių elementų programa palygintos su eksperimentų metu gautomis momentų ir kreivių diagramomis. Gautas geras šių diagramų sutapimas.

scholarly journals Passive arching in rubberized sand backfills

2020 ◽  
Vol 57 (4) ◽  
pp. 549-567
Author(s):  
Hamidreza Khatami ◽  
An Deng ◽  
Mark Jaksa
Keyword(s):  
Deformation Process ◽  
High Speed ◽  
Pressure Sensors ◽  
Coarse Sand ◽  
Image Correlation ◽  
Correlation Technique ◽  
High Speed Imaging ◽  
Digital Image Correlation Technique ◽  
Stress Profiles ◽  
Stress Variations

The deformation and stress profiles of passive arching in a coarse sand and two rubberized sand backfills were investigated using a trapdoor apparatus. The trapdoor apparatus was instrumented with high-speed imaging equipment and a series of pressure sensors. The images of the deformation process in the backfills were analysed using the digital image correlation technique. The effect of a local surcharge on the deformation and stress profiles was also examined. It was observed that the rubber inclusions helped reduce the deformation of the backfills. Passive arching moduli and stress variations between the backfills examined are compared.

Mixed-Mode I/II Crack Extension in Thin Sheet Metal

2013 ◽  
Vol 275-277 ◽  
pp. 156-159 ◽  
Author(s):  
Yong Ping Shao ◽  
Bang Cheng Yang ◽  
Chun Ran ◽  
Jing Lv
Keyword(s):  
Mixed Mode ◽  
Fracture Criterion ◽  
Thin Sheet ◽  
Image Correlation ◽  
Correlation Technique ◽  
Sheet Metals ◽  
Large Plastic Deformation ◽  
Digital Image Correlation Technique ◽  
Thin Sheet Metal ◽  
Quantitative Analyses

Real-time displacement in stable crack tearing was measured by digital image correlation technique. Quantitative analyses were provided on mixed-mode Ⅰ/Ⅱ fracture and critical CTOA for recycled thin sheet metals. It is shown that the fracture of recycled thin sheet metals is tough due to the large plastic deformation, and mixed-mode crack is easier to extend than mode Ⅰ crack. The critical CTOA at stable crack tearing is constant and can be used as a fracture criterion for the thin sheet metals.

scholarly journals OS0705 Measurement of Displacement Field around the Mixed-mode Crack using Digital Image Correlation

2008 ◽  
Vol 2008 (0) ◽  
pp. _OS0705-1_-_OS0705-2_
Author(s):  
Kenichi SHIMIZU ◽  
Tashiyuki TORII ◽  
Kenta TSUNEYASU ◽  
Kensaku SHINOHARA
Keyword(s):  
Digital Image Correlation ◽  
Digital Image ◽  
Displacement Field ◽  
Mixed Mode ◽  
Image Correlation ◽  
Mixed Mode Crack

scholarly journals TESTING OF HYBRID NICKEL-POLYURETHANE FOAMS AT HIGH STRAIN-RATES USING HOPKINSON BAR AND DIGITAL IMAGE CORRELATION

2018 ◽  
Vol 18 ◽  
pp. 72 ◽  
Author(s):  
Marcel Adorna ◽  
Petr Zlámal ◽  
Tomáš Fíla ◽  
Jan Falta ◽  
Markus Felten ◽  
...  
Keyword(s):  
Digital Image Correlation ◽  
Digital Image ◽  
High Speed ◽  
Split Hopkinson Pressure Bar ◽  
Dynamic Equilibrium ◽  
Polyurethane Foams ◽  
Frame Rate ◽  
Image Correlation ◽  
Correlation Technique ◽  
High Speed Camera

In this paper Split Hopkinson pressure bar (SHPB) was used for dynamic testing of nickel coated polyurethane hybrid foams. The foams were manufactured by electrodeposition of a nickel coating on the standard open-cell polyurethane foam. High strength aluminium alloy bars instrumented with foil strain-gauges were used for dynamic loading of the specimens. Experiments were observed using a high-speed camera with frame-rate set to approx. 100-150 kfps. Precise synchronisation of the high-speed camera and the strain-gauge record was achieved using a through-beam photoelectric sensor. Dynamic equilibrium in the specimen was achieved in all measurements. Digital image correlation technique (DIC) was used to evaluate in-plane displacements and deformations of the samples. Specimens of two different dimensions were tested to investigate the collapse of the foam structure under high-speed loading at the specific strain-rate and strain.

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