scholarly journals Modeling of Bimodular Bone Specimen under Four-Point Bending Fatigue Loading

Materials ◽  
2022 ◽  
Vol 15 (2) ◽  
pp. 474
Author(s):  
Yufan Yan ◽  
Xianjia Meng ◽  
Chuanyong Qu
Keyword(s):  
Compressive Strain ◽  
Fatigue Loading ◽  
Degradation Process ◽  
Neutral Axis ◽  
Image Correlation ◽  
Bending Test ◽  
Correlation Technique ◽  
Fatigue Process ◽  
Four Point Bending ◽  
Bone Properties

The fatigue damage behavior of bone has attracted significant attention in both the mechanical and orthopedic fields. However, due to the complex and hierarchical structure of bone, describing the damage process quantitively or qualitatively is still a significant challenge for researchers in this area. In this study, a nonlinear bi-modulus gradient model was proposed to quantify the neutral axis skewing under fatigue load in a four-point bending test. The digital image correlation technique was used to analyze the tensile and compressive strains during the fatigue process. The results showed that the compressive strain demonstrated an obvious two-stage ascending behavior, whereas the tensile strain revealed a slow upward progression during the fatigue process. Subsequently, a theoretical model was proposed to describe the degradation process of the elastic modulus and the movement of the neutral axis. The changes in the bone properties were determined using the FEM method based on the newly developed model. The results obtained from two different methods exhibited a good degree of consistency. The results obtained in this study are of help in terms of effectively exploring the damage evolution of the bone materials.

scholarly journals Evolution of the reinforced I-beam strain state

2018 ◽  
Vol 143 ◽  
pp. 01017 ◽  
Author(s):  
Artem Ustinov ◽  
Anatolij Klopotov ◽  
Aleksandr Potekaev ◽  
Vasilij Plevkov ◽  
Ekaterina Marchenko
Keyword(s):  
Composite Material ◽  
Strain State ◽  
Image Correlation ◽  
Correlation Technique ◽  
Digital Image Correlation Technique ◽  
Load Bearing Capacity ◽  
Four Point Bending ◽  
Reinforced Beams ◽  
State Evolution ◽  
Bending Loading

The paper presents experimental results of the strain state evolution of the steel I-beam reinforced with composite material under four-point bending loading. Digital image correlation technique was used to trace the evolution of plastic strain zones distribution. The images of longitudinal relative strain on the lateral surface of the reinforced I-beam web were obtained and analyzed. It was found that the increase of load-bearing capacity of the reinforced beams can exceed 26 %.

scholarly journals Nondestructive Monitoring Techniques for Crack Detection and Localization in RC Elements

2020 ◽  
Vol 10 (9) ◽  
pp. 3248 ◽  
Author(s):  
Marco Domaneschi ◽  
Gianni Niccolini ◽  
Giuseppe Lacidogna ◽  
Gian Paolo Cimellaro
Keyword(s):  
Crack Detection ◽  
Visual Observation ◽  
Image Correlation ◽  
Bending Test ◽  
Nondestructive Monitoring ◽  
Integrated Monitoring ◽  
Four Point Bending ◽  
Initiation And Propagation ◽  
Detection And Localization ◽  
Good Agreement

This paper presents the structural and damage assessment of a reinforced concrete (RC) beam subjected to a four-point bending test until yielding of reinforcing steel. The deterioration progress was monitored using different nondestructive testing (NDT) techniques. The strain was measured by distributed fiber optic sensors (FOSs), embedded prior to concrete pouring. The initiation and propagation of cracks were monitored by acoustic emission (AE) sensors attached to the surface of the material. The recorded AE activity results in good agreement with FOS strain measurements. The results of the integrated monitoring system are confirmed by visual observation of the actual crack pattern. At different loading steps, digital image correlation (DIC) analysis was also conducted.

The Role of Multiscale Strain Localizations in Fatigue of Magnesium Alloys

2014 ◽  
Author(s):  
Jefferson Cuadra ◽  
Kavan Hazeli ◽  
Michael Cabal ◽  
Antonios Kontsos
Keyword(s):  
Fatigue Life ◽  
Magnesium Alloys ◽  
Fatigue Behavior ◽  
Fatigue Crack Initiation ◽  
Fatigue Loading ◽  
Degradation Process ◽  
Electron Back Scatter Diffraction ◽  
Image Correlation ◽  
Deformation Mechanisms ◽  
Global Strain

The reliable characterization of fatigue behavior and progressive damage of advanced alloys relies on the monitoring and quantification of parameters such as strain localizations as a result of both crystallographic deformation mechanisms and bulk response. To this aim, this article attempts to directly correlate microstructural strain at specific fatigue life to global strain as well as surface roughness in Magnesium alloys. Strain at the grain scale is calculated using Digital Image Correlation (DIC), while surface topography gradients are computed using roughness data at different stages of the fatigue life. The results are further correlated to Electron Back Scatter Diffraction (EBSD) measurements which reveal the profuse and spatially inhomogeneous nature of the crystallographic deformation mechanisms related to yielding and fatigue crack initiation. Emphasis is given on using multimodal NDE data to formulate first a description of the current state of the material subjected to fatigue loading and on identifying conditions that can probabilistically drive the affected by both local and global response, governing degradation process.

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 Design Criteria for Scantling of Longitudinal and Transverse Connections in the Torsion Box Under Fatigue Loading

2021 ◽  
Vol 28 (2) ◽  
pp. 116-127
Author(s):  
Arturo Silva-Campillo ◽  
Juan Carlos Suárez-Bermejo ◽  
Miguel Ángel Herreros-Sierra
Keyword(s):  
Failure Modes ◽  
High Stress ◽  
Fatigue Loading ◽  
Image Correlation ◽  
Correlation Technique ◽  
Two Phase ◽  
High Stress Concentration ◽  
Phase Study ◽  
Propagation Law ◽  
Static Regime

Abstract Fatigue is one of the main failure modes in marine structures, and it is caused by the strong cyclic characteristics of the loads they support. This failure mode is amplified in areas of high stress concentration, such as at the intersection of primary and secondary elements. In this paper, a two-phase study is proposed that compares numerical and experimental results using a digital image correlation technique. The described procedure establishes selection, design, and scantling criteria and provides recommendations for the design of the transverse structure using specimens with different geometries. These geometries correspond to different designs for the transverse primary structure that use a longitudinal secondary stiffener with variable thickness and longitudinal spacing to transverse in a dynamic and quasi-static regime. The stress state for this regime is calculated based on the biaxiality indication concept, which uses the fatigue phenomenon (safety factor and sensitivity curves) and fracture mechanics (parameters of the Paris crack propagation law, correlation value, and law of variation of the stress intensity factor).

Modeling of Deformation and Fracture of Concrete Structures with FRP Reinforcement

2015 ◽  
Vol 752-753 ◽  
pp. 685-688
Author(s):  
Andrey Benin ◽  
S.G. Semenov ◽  
Artem S. Semenov
Keyword(s):  
Image Correlation ◽  
Bending Test ◽  
Four Point Bending ◽  
Reinforced Plastic ◽  
Deformation And Fracture ◽  
Different Types ◽  
Loading Case ◽  
Frp Reinforcement ◽  
Four Point Bending Test ◽  
Frp Bars

Carrying capacity and fracture modes of concrete beams reinforced by different types of fiber reinforced plastic (FRP) bars are analyzed experimentally and numerically. The four-point-bending test is used as a typical loading case for this purpose. Synchronous registration of loading level, displacements and strains is performed by using InstronTM servohydraulic machine, LVDT sensors, strain gauges and digital image correlation Vic3DTM system. The experimental data and results of finite element simulations are compared and discussed.

scholarly journals Experimental Investigation on the Mechanical Behavior of Bovine Bone Using Digital Image Correlation Technique

2015 ◽  
Vol 2015 ◽  
pp. 1-6 ◽  
Author(s):  
Yuxi Chen ◽  
Diansen Yang ◽  
Yongshang Ma ◽  
XianJun Tan ◽  
Zhan Shi ◽  
...  
Keyword(s):  
Digital Image Correlation ◽  
Digital Image ◽  
Image Correlation ◽  
Bending Test ◽  
Displacement Sensor ◽  
Fracture Mechanisms ◽  
Correlation Technique ◽  
Bovine Bone ◽  
Full Field ◽  
Force Direction

In order to understand the fracture mechanisms of bone subjected to external force well, an experimental study has been performed on the bovine bone by carrying out the three-point bending test with 3D digital image correlation (DIC) method, which provides a noncontact and full field of displacement measurement. The local strain and damage evolution of the bone has been recorded real time. The results show that the deflection measured by DIC agrees well with that obtained by the displacement sensor of the mechanical testing machine. The relationship between the deflection and the force is nearly linear prior to reaching the peak strength which is about 16 kN for the tested bovine tibia. The full-field strain contours of the bone show that the strain distribution depends on not only the force direction, but also the natural bone shape. The natural arched-shape bovine tibia bone could bear a large force, due to the tissue structure with high strength, and the fracture propagation process of the sample initiates at the inner side of the bone first and propagates along the force direction.

Theoretical and experimental considerations on the neutral axis of wood beams with a hole in different locations

Holzforschung ◽  
2018 ◽  
Vol 72 (9) ◽  
pp. 769-777
Author(s):  
Yuxin Wen ◽  
Ping Yang ◽  
Jian Zhao ◽  
Dong Zhao
Keyword(s):  
Solid Wood ◽  
Neutral Axis ◽  
Experimental Results ◽  
Image Correlation ◽  
Plastic Behavior ◽  
Tension Zone ◽  
Compression Zone ◽  
Four Point Bending ◽  
Wood Beams ◽  
Dic Technique

AbstractHoles contribute to the non-homogeneous nature of solid wood and shift the neutral axis of wood beams away from the centroid. Based on the plane-section assumption and idealized trapezoidal distribution, new calculating formulas will be presented in terms of the location of neutral axis for clear beams and wood beams with a hole at the center, compression zone and tension zone. To verify the results of theoretical analysis and formulas, four-point bending experiments of wood beams were performed by a digital image correlation (DIC) technique. There is a reasonable agreement between calculated and experimental results with a hole at the center or in the compression zone of the beams. Concerning a hole in the tension zone, on the other hand, the calculated locations of neutral axis are not in agreement with the experimental results, due to the plastic behavior on both the compression and tension zones of the beams in the inelastic stage.

scholarly journals Detection of Multiple Cracks in Four-Point Bending Tests Using the Coda Wave Interferometry Method

Sensors ◽  
2020 ◽  
Vol 20 (7) ◽  
pp. 1986 ◽  
Author(s):  
Xin Wang ◽  
Joyraj Chakraborty ◽  
Antoine Bassil ◽  
Ernst Niederleithinger
Keyword(s):  
Fiber Optics ◽  
Large Scale ◽  
Early Stage ◽  
Image Correlation ◽  
Bending Test ◽  
Coda Wave ◽  
Multiple Cracks ◽  
Rc Structures ◽  
Four Point Bending ◽  
Coda Wave Interferometry

The enlargement of the cracks outside the permitted dimension is one of the main causes for the reduction of service life of Reinforced Concrete (RC) structures. Cracks can develop due to many causes such as dynamic or static load. When tensile stress exceeds the tensile strength of RC, cracks appear. Traditional techniques have limitations in early stage damage detection and localisation, especially on large-scale structures. The ultrasonic Coda Wave Interferometry (CWI) method using diffuse waves is one of the most promising methods to detect subtle changes in heterogeneous materials, such as concrete. In this paper, the assessment of the CWI method applied for multiple cracks opening detection on two specimens based on four-point bending test is presented. Both beams were monitored using a limited number of embedded Ultrasonic (US) transducers as well as other transducers and techniques (e.g., Digital Image Correlation (DIC), LVDT sensors, strain gauges, and Fiber Optics Sensor (FOS)). Results show that strain change and crack formation are successfully and efficiently detected by CWI method even earlier than by the other techniques. The CWI technique using embedded US transducers is undoubtedly a feasible, efficient, and promising method for long-term monitoring on real infrastructure.

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