Academic literature on the topic 'Digital correlation of images (DIC)'
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Journal articles on the topic "Digital correlation of images (DIC)"
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Suswanto, Budi, Data Iranata, and Yanisfa Septiarsilia. "Analysis of Steel Material Characteristics using Digital Image Correlation (DIC) Method." MEDIA KOMUNIKASI TEKNIK SIPIL 30, no. 1 (2024): 95–104. http://dx.doi.org/10.14710/mkts.v30i1.59491.
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The use of steel materials in building construction opens new opportunities for sustainable development, as steel exhibits corrosion resistance, durability, and reliability in terms of strength and ductility. Digital Image Correlation (DIC) is non-contact technique in which digital images of the surface of a test object are captured using high-resolution cameras. This study conducted measurements of strain distribution on the specimen's surface using the DIC method throughout the entire tensile testing process. The study particularly focuses on examining changes in strain distribution during the melting phase and the local deformation phase leading to fracture. In this research, a comparison will be made between the load-displacement curves obtained from experimental laboratory testing and the results analyzed using the DIC method for SS400-grade steel material. Based on the results of the tensile test and DIC analysis that have been conducted, conclusions have been drawn in the research. The tensile test results of SS400 steel material with a thickness of 6 mm, 8 mm, 10 mm, and 12 mm meet the quality requirements in the tested specification standards, and the results of the force-displacement curve between the experimental test results and the DIC method obtained a minimum deviation with a value below 10%,. Therefore, it can be concluded that the DIC method exhibits a reasonably good level of accuracy, making it suitable for validating the results of experimental tests.
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Atkinson, Devan, and Thorsten Hermann Becker. "Stereo Digital Image Correlation in MATLAB." Applied Sciences 11, no. 11 (2021): 4904. http://dx.doi.org/10.3390/app11114904.
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Digital Image Correlation (DIC) has found widespread use in measuring full-field displacements and deformations experienced by a body from images captured of it. Stereo-DIC has received significantly more attention than two-dimensional (2D) DIC since it can account for out-of-plane displacements. Although many aspects of Stereo-DIC that are shared in common with 2D DIC are well documented, there is a lack of resources that cover the theory of Stereo-DIC. Furthermore, publications which do detail aspects of the theory do not detail its implementation in practice. This literature gap makes it difficult for newcomers to the field of DIC to gain a deep understanding of the Stereo-DIC process, although this knowledge is necessary to contribute to the development of the field by either furthering its capabilities or adapting it for novel applications. This gap in literature acts as a barrier thereby limiting the development rate of Stereo-DIC. This paper attempts to address this by presenting the theory of a subset-based Stereo-DIC framework that is predominantly consistent with the current state-of-the-art. The framework is implemented in practice as a 202 line MATLAB code. Validation of the framework shows that it performs on par with well-established Stereo-DIC algorithms, indicating it is sufficiently reliable for practical use. Although the framework is designed to serve as an educational resource, its modularity and validation make it attractive as a means to further the capabilities of DIC.
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Zhang, Rui. "Elastic Parameters Measurement of Rubber by Digital Image Correlation." Applied Mechanics and Materials 444-445 (October 2013): 1532–35. http://dx.doi.org/10.4028/www.scientific.net/amm.444-445.1532.
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Application of Digital image correlation method (DIC) to measure the elastic modulus and Poisson ratio of rubber under compression is investigated in this paper. Surface images of the rubber surface subjected to various loading were captured using a CCD camera. DIC is subsequently used to obtain displacement field by correlating the images captured before and after deformation, and then the average compression strain is obtained by fitting the displacement using linear plane. The slope of each set of applied stress versus measured strain data is calculated by least-squares linear regression. The elastic modulus and Poisson ratio obtained from DIC, are compared to that determined from the dial gauge, which shows that they are in good accordance with existing data. Experimental results clearly show that DIC is suitable for accurate measurement the elastic modulus of rubber.
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Uzun, Fatih, and Alexander M. Korsunsky. "Digital Image Correlation for Elastic Strain Evaluation during Focused Ion Beam Ring-Core Milling." Journal of Manufacturing and Materials Processing 8, no. 4 (2024): 144. http://dx.doi.org/10.3390/jmmp8040144.
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The utilization of the focused ion beam digital image correlation (FIB-DIC) technique for measuring in-plane displacements and the employment of the height digital image correlation (hDIC) technique as two-step DIC for determining both in-plane and out-of-plane displacements within the region of interest are detailed in this paper. Consideration is given to the microscopy data’s measurement scale and resolution to confirming the capability of both techniques to conduct micro-scale correlations with nano-scale sensitivity, thereby making it suitable for investigating the residual elastic strains formed due to processing. The sequential correlation procedure of the FIB-DIC technique has been optimized to achieve a balance between accuracy and performance for correlating sequential scanning electron microscope images. Conversely, the hDIC technique prioritizes the accurate correlation of SEM images directly with the reference state without a sequential procedure and offers optimal computational performance through advanced parallel computing tools, particularly suited for correlating profilometry data related to large-scale displacements. In this study, the algorithm of the hDIC technique is applied as two-step DIC to evaluate the elastic strain relaxation on the surface of a ring-core drilled using focused ion beam. Both techniques are utilized to correlate the same scanning electron microscope images collected during the monitoring of the ring drilling process. A comparison of the correlation results of both techniques is undertaken regarding the quantification of the near-surface residual elastic strains, with the analysis conducted to discern the superior accuracy of the hDIC algorithm. Furthermore, the distinctions between the two techniques are delineated and discussed.
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Jarrett, Steven R., Thinh Q. Thai, Lindsey J. Rowley, Weston D. Craig, and Ryan B. Berke. "The Effect of Bit Depth on High-Temperature Digital Image Correlation Measurements." Journal of Sensors 2022 (June 2, 2022): 1–19. http://dx.doi.org/10.1155/2022/6554128.
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Digital Image Correlation (DIC) is a camera-based method of measuring displacement and strain. High-temperature DIC is challenging due to light emitted from the sample which can saturate the image. This effect can be mitigated using optical bandpass filters, but the maximum sample temperature range of DIC remains dependent on the camera and camera settings. Among camera settings, bit depth, also referred to as color depth or number of bits, has received insufficient attention in high-temperature DIC literature. In this work, the effect of bit depth on DIC measurements is investigated both analytically and experimentally. It is shown that if image noise is sufficiently low, then increasing bit depth reduces DIC random error. A new metric, the effective number of bits, is presented to determine the appropriate number of bits for DIC images. Using increased bit depth, reduced exposure time, and low-noise images, the maximum sample temperature for DIC measurements was shown to increase without negatively impacting random error.
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Bailey, Daniel. "Using Digital Image Correlation to Measure Full Field Strain." AM&P Technical Articles 172, no. 10 (2014): 23–24. http://dx.doi.org/10.31399/asm.amp.2014-10.p023.
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Abstract Existing strain measurement techniques do not offer enough information about how failures occur, so alternative methods are needed. One technique involves using digital image correlation (DIC) to measure full field strain over the entire material surface. DIC works by capturing a series of images throughout a test and analyzing them afterwards.
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Dan, Xizuo, Junrui Li, Qihan Zhao, Fangyuan Sun, Yonghong Wang, and Lianxiang Yang. "A Cross-Dichroic-Prism-Based Multi-Perspective Digital Image Correlation System." Applied Sciences 9, no. 4 (2019): 673. http://dx.doi.org/10.3390/app9040673.
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A robust three-perspective digital image correlation (DIC) system based on a cross dichroic prism and single three charge-coupled device (3CCD) color cameras is proposed in this study. Images from three different perspectives are captured by a 3CCD camera using the cross dichroic prism and two planar mirrors. These images are then separated by different CCD channels to perform correlation calculation with an existing multi-camera DIC algorithm. The proposed system is considerably more compact than the conventional multi-camera DIC system. In addition, the proposed system has no loss of spatial resolution compared with the traditional single-camera DIC system. The principle and experimental setup of the proposed system is described in detail, and a series of tests is performed to validate the system. Experimental results show that the proposed system performs well in displacement, morphology, and strain measurement.
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Chen, Jiangping, and Weijun Tao. "Gradient-Based Automatic Exposure Control for Digital Image Correlation." Sustainability 15, no. 2 (2023): 1149. http://dx.doi.org/10.3390/su15021149.
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Digital image correlation (DIC) is widely used in material experiments such as ores; the quality of a speckle image directly affects the accuracy of the DIC calculation. This study aims to acquire high-quality speckle pattern images and improve the calculation accuracy and stability. A gradient-based image quality metric was selected to evaluate the image quality, and its validity was verified by a rigid body experiment and a numerical experiment. Based on the maximum image quality metric, an automatic exposure control algorithm and the control procedure were proposed to obtain the optimal exposure time. Finally, nine sets of images with different poses and illuminations were captured, and displacement and strain fields were calculated at the fixed exposure time and the optimized exposure time. The results of the rigid-body motion experiment show that the calculated data at the optimized exposure time is smoother and less noisy, and the error is smaller, which verifies the effectiveness of the exposure control procedure and its algorithm and improves the accuracy and stability of DIC calculation.
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Giancane, Simone, Riccardo Nobile, Francesco W. Panella, and Vito Dattoma. "Damage Evolution of Composite Laminates with Digital Image Correlation." Key Engineering Materials 452-453 (November 2010): 377–80. http://dx.doi.org/10.4028/www.scientific.net/kem.452-453.377.
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DIC (Digital Image Correlation) based methodology gives full field measure of the displacement using a well defined algorithm for matching the images of loaded and load free component, so that displacement in a plane can be evaluated for a certain number of grid reference points on the analysed surface. In this work, the authors present an application of DIC technique to analyse fatigue damage phenomena in two notched GFRC laminates under tensile load. Damage analysis based on optical DIC technique has been performed to detect the damaged areas on the specimen surface. The damage evolution and failure mechanism has been followed monitoring two parameters: the local hysteresis area of stress-strain cycles, the local stiffness variation.
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Lim, Chhoung, Yeongseok Jeong, Suchart Limkantanyu, and Minho Kwon. "Strain Measuring of Composite Grid Using Digital Image Correlation." Advances in Materials Science and Engineering 2022 (April 14, 2022): 1–12. http://dx.doi.org/10.1155/2022/6041887.
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Digital Image Correlation (DIC) is a new advanced technique for measuring the deformation of a specimen using high-resolution images. It has been used by numerous researchers since it can measure the deformation of specimens without interference because it is contactless. Moreover, the DIC technique can be applied to any materials to which normal measuring equipment is difficult to attach such as Fiber-Reinforced Polymer (FRP) grid in this paper, undulated and small surfaces. The DIC technique is easy to set up and provides reliable results compared to conventional equipment like a strain gauge. Although it is good, its associated equipment is too expensive to be readily affordable. Hence, this paper uses an open-source DIC program called Ncorr that works in MATLAB to analyze deformations of six FRP grids from direct tensile tests by comparing their results to the results from a strain gauge. Young’s modulus—calculated from ASTM 3039, ACI 440-3R-04, and regression analysis—of each specimen will be used for comparison. The results show that the difference between Young’s modulus from DIC and strain gauge is <5% if the stress–strain graph of data from the strain gauge is perfectly linear without straying.
Dissertations / Theses on the topic "Digital correlation of images (DIC)"
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Thai, Thinh Quang. "Importance of Exposure Time on Digital Image Correlation (DIC) at Extreme Temperatures." DigitalCommons@USU, 2018. https://digitalcommons.usu.edu/etd/7067.
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Extreme temperatures have increasingly played an important role in engineering applications, including leading edges during hypersonic flight, spacecraft re-entry, and propulsion systems. In order to design for such thermo-mechanical conditions, materials must be characterized using suitable measurement methods. DIC is a popular and versatile method in full-field measurement. In brief, DIC compares images of a sample between its undeformed and deformed state in order to get displacement and strain field maps. Since the images are acquired from digital cameras, it is important to have high contrast images for meaningful correlation. Exposure time is a pivotal camera setting relating to camera sensitivity. Alteration in exposure time results in variation of image contrast, thereby affecting DIC correlation. Also, it is well known that at extreme temperatures, materials emit light which can saturate DIC camera sensors, but the light can be mitigated using optical bandpass filters. In previous work, many have shown that blue bandpass filters can effectively extend the temperature range of DIC, and our lab has shown that ultraviolet (UV) filters can extend the range further.
In this thesis, four different temperatures: room temperature, 1300°C, 1450°C, and 1600°C were tested by rigid-motion experiments. At each temperature level, UV images were acquired in order to examine the variation of DIC error over the whole range of exposure time. UV images were acquired at exposure times ranging from 500μs to 61,000μs, which are the minimum and maximum possible values for the cameras used in this thesis. The results showed that there were higher errors of UV-DIC at extremely dark or bright exposure times where as errors were generally insignificant at intermediate exposure times. In order to perform meaningful DIC up to 1600oC, the exposure time for the camera used in this thesis is suggested to be set between 10,000μs and 40,000μs.
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Lim, WeiChiang Eric. "EMBEDDED SPECKLE BONDLINE DEFECT DETECTION USING ULTRASONIC DIGITAL IMAGE CORRELATION (UT-DIC)." OpenSIUC, 2018. https://opensiuc.lib.siu.edu/theses/2391.
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The primary objective of this research is to conduct further evaluation of ultrasonic digital image correlation (UT-DIC) on strain map analysis and defect detection of adhesive joints with embedded speckle pattern. UT-DIC is a non-destructive evaluation method that utilized ultrasonic C-scan images for whole field strain and displacement analysis. Acrylic glass, epoxy resin system and metal shavings with high acoustic impedance of a specific weight were used to create the samples which were loaded under tension. Defects with varying shapes and sizes were implemented by surface preparation to understand the limits of this approach. UT-DIC and optical DIC strain map results were compared, and it was found that each approach detected certain shapes of defect better than the other.
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Lindner, Dominik. "Towards the fracture prediction of turbomachinery disks : a contribution of the digital image correlation." Thesis, Université Paris-Saclay (ComUE), 2016. http://www.theses.fr/2016SACLN023/document.
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Cette thèse s'intéresse à l'amélioration de la prévision de l'éclatement des pièces tournantes des turbomachines. L'axe de recherche principal a été celui de l'identification du comportement du matériau jusqu'à rupture pour des sollicitations multi-axiales représentatives et l'identification des conditions de rupture locale elles mêmes. Pour cela une approche basée sur la corrélation d'image numérique intégrée a été suivie. L'autre axe abordé dans cette thèse a été celui de la prévision objective et robuste de la rupture par la mécanique de l'endommagement dans le cadre de simulations explicites utilisant des techniques de scaling pour diminuer les temps de calcul. Deux matériaux ont été étudiés, un alliage titane TA6V et un alliage nickel Udimet 500. Des éprouvettes ont été définies pour permettre d'avoir des sollicitations proches de celles en service et pour permettre d'utiliser des techniques de mesure de champs. Un code commercial (ABAQUS) est utilisé dans une approche intégrée de la corrélation des images numériques (CIN). Le principe de ces méthodes est d'optimiser la corrélation directement à partir des paramètres du modèle sans passer par une procédure intermédiaire demandant de reconstruire préalablement les champs de déformations. Cette technique, qui peut-être vu comme très régularisante, confère à la méthode une grande robustesse, ce qui permet d'obtenir des informations même en présence de mouchetis dégradés lors des phases ultimes de chargement. L'ensemble des paramètres constitutifs des modèles peut alors être identifié avec un seul essai hétérogène. Dans l'étude un accent particulier a été mis sur l'analyse des champs de triaxialité, dont l'importance sur les conditions de rupture est suspectée, en utilisant des éprouvettes fines et des éprouvettes épaisses. Des lois de comportement ont pu être identifié pour des niveaux de déformations plastiques jusqu'à 3 fois supérieurs à ceux atteints dans des essais de traction uni-axiaux et ceci en présence d'adoucissement global. L'intégration étroite des essais et des simulations a également permis d'analyser l'état de déformation et contraintes des éléments proches de la surface de rupture juste avant celle-ci et ainsi de tester des critères de rupture potentiels avec un grand nombre de données. Pour la seconde partie de la thèse, plus exploratoire faute de temps, une étude préliminaire a porté sur la possibilité d'utiliser des modèles à taux d'endommagement limités combinés avec des techniques de scaling pour utiliser des simulations explicites dans le cadre de sollicitations centrifuges quasi-statiques. Les premiers résultats montrent qu'une accélération est possible avec des niveaux d'erreurs relativement bas sur les vitesses de rotation conduisant à la rupture et ceci dans des temps comparables avec des simulations implicites quasi-statique, l'avantage étant la robustesse des analyses en dynamique explicite<br>This thesis addresses the amelioration of the burst prediction of turbo-engines rotating parts.The principal axis of this study was the identification of the material behaviour up fracture under multi-axial loading and the identification of the local condition at failure. To accomplish this, an integrated digital image correlation approach was employed.The other thematic axis of this thesis was the objective and robust prediction of rupture using the damage mechanics in the framework of explicit simulations and the study of the influence, on the prediction, of various scaling techniques used to decrease the computation time.Two materials were studied, the titanium alloy TA6V and the nickel alloy Udimet 500. The samples were defined to guarantee similar loading conditions as those in the disks in service and to allow the use of field measurement techniques.A commercial code (ABAQUS) is used in an integrated approach to Digital Image Correlation (DIC). The principle of this method is to optimize the correlation of the test directly with the model parameters without passing by an intermediate procedure requiring the reconstruction of the deformation field beforehand. This technique, which can be seen as highly regularising, grants a considerable robustness to the method, which allows obtaining information from degraded speckle patterns encountered at the end of the test. The entire set of constitutive parameters can be identified with only one heterogeneous test. Within this study, a particular accent was laid on the analysis of triaxiality fields by using thin and thick samples. The importance of these fields for the fracture conditions is suspected.Constitutive models were identified for plastic strains that were about three times higher than the ones achievable in uniaxial tensile test on smooth sample.The close integration of the experiments and simulations allowed the analysis of deformation and stresses of the elements near the failure surface at the instant just before failure. This allowed the testing of different criteria with a large amount of data.For the second axis of the thesis, preliminary studies examined the possibility to use limited damage rate models combined with scaling techniques. These latter allow performing explicit simulations in context of a centrifugal quasi-static loading. The results show that acceleration is possible. The errors of the rotational speeds, which lead to disk fracture, are relatively low. The simulation times are comparable to implicit quasi-static simulations, while the main advantage is the maintained robustness in explicit simulations
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Jeong, Gi Young. "Tensile Properties of Loblolly Pine Strands Using Digital Image Correlation and Stochastic Finite Element Method." Diss., Virginia Tech, 2008. http://hdl.handle.net/10919/29563.
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Previous modeling of wood materials has included many assumptions of unknown mechanical properties associated with the hierarchical structure of wood. The experimental validation of previous models did not account for the variation of mechanical properties present in wood materials. Little research has explored the uncertainties of mechanical properties in earlywood and latewood samples as well as wood strands. The goal of this study was to evaluate the effect of the intra-ring properties and grain angles on the modulus of elasticity (MOE) and ultimate tensile strength (UTS) of different orientation wood strands and to analyze the sensitivity of the MOE and UTS of wood strands with respect to these variables.
Tension testing incorporating digital image correlation (DIC) was employed to measure the MOE and UTS of earlywood and latewood bands sampled from growth ring numbers 1-10 and growth ring numbers 11-20. A similar technique adjusted for strand size testing was also applied to measure the MOE and UTS of different orientation wood strands from the two growth ring numbers. The stochastic finite element method (SFEM) was used with the results from the earlywood and latewood testing as inputs to model the mechanical property variation of loblolly pine wood strands. A sensitivity analysis of the input parameters in the SFEM model was performed to identify the most important parameters related to mechanical response.
Modulus of elasticity (MOE), Poisson ratio, and ultimate tensile strength (UTS) from earlywood and latewood generally increased as the growth ring number increased except for the UTS of latewood, which showed a slight decrease. MOE and UTS from radial, tangential, and angled grain orientation strands increased as the growth ring numbers increased while MOE and UTS from cross-grain strands decreased as the growth ring number increased. Shear modulus of wood strands increased as the growth ring number increased while shear strength decreased as the growth ring number increased. Poisson ratio from radial and angled grain strands decreased as the growth ring number increased while Poisson ratio from tangential and cross grain orientation strands increased as the growth ring number increased.
The difference of average MOE from different grain strands between experimental results and SFEM results ranged from 0.96% to 22.31%. The cumulative probability distribution curves from experimental tests and SFEM results agreed well except for the radial grain models from growth ring numbers 11-20. From sensitivity analysis, earlywood MOE was the most important contributing factor to the predicted MOE from different grain orientation strand models. From the sensitivity analysis, earlywood and latewood participated differently in the computation of MOE of different grain orientation strand models. The predicted MOE was highly associated with the strain distribution caused by different orientation strands and interaction of earlywood and latewood properties. In general, earlywood MOE had a greater effect on the predicted MOE of wood strands than other SFEM input parameters.
The difference in UTS between experimental and SFEM results ranged from 0.09% to 11.09%. Sensitivity analysis showed that grain orientation and growth ring number influenced the UTS of strands. UTS of strands from growth ring numbers 1-10 showed strength indexes (Xt, Yt, and S) to be the dominant factors while UTS of strands from growth ring numbers 11-20 showed both strength indexes and stress components (Ï 1, Ï 2, and Ï 12) to be the dominant factors. Grain orientations of strands were a strong indicator of mechanical properties of wood strands.<br>Ph. D.
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Poudel, Anish. "BOND STRENGTH EVALUATION IN ADHESIVE JOINTS USING NDE AND DIC METHODS." OpenSIUC, 2015. https://opensiuc.lib.siu.edu/dissertations/1010.
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Adhesive bonding of graphite epoxy composite laminates to itself or traditional metal alloys in modern aerospace and aircraft structural applications offers an excellent opportunity to use the most efficient and intelligent combination of materials available thus providing an attractive package for efficient structural designs. However, one of the major issues of adhesive bonding is the occasional formation of interfacial defects such as kissing or weak bonds in the bondline interface. Also, there are shortcomings of existing non-destructive evaluation (NDE) methods to non-destructively detect/characterize these interfacial defects and reliably predicting the bond shear strength. As a result, adhesive bonding technology is still not solely implemented in primary structures of an aircraft. Therefore, there is a greater demand for a novel NDE tool that can meet the existing aerospace requirement for adhesive bondline characterization. This research implemented a novel Acoustography ultrasonic imaging and digital image correlation (DIC) technique to detect and characterize interfacial defects in the bondline and determine bond shear strength in adhesively bonded composite-metal joints. Adhesively bonded Carbon Fiber Reinforced Plastic (CFRP) laminate and 2024-T3 Aluminum single lap shear panels subjected to various implanted kissing/weak bond defects were the primary focus of this study. Kissing/weak bonds were prepared by controlled surface contamination in the composite bonding surface and also by improperly mixing the adhesive constituent. SEM analyses were also conducted to understand the surface morphology of substrates and their interaction with the contaminants. Morphological changes were observed in the microscopic scale and the chemical analysis confirmed the stability of the contaminant at or very close to the interface. In addition, it was also demonstrated that contaminants migrated during the curing of the adhesive from CFRP substrate which caused a decrease of bond shear strength in single lap shear test samples. Through-transmission ultrasonics (TTU) Acoustography at 3.8 MHz showed promising results on the detectability of bondline defects in adhesively bonded CFRP-Al lap shear test samples. A correlation between Acoustography ultrasonic attenuation and average bond shear strength in CFRP-Al lap shear panels demonstrated that differential attenuation increased with the reduction of the bond shear strength. Similarly, optical DIC tests were conducted to identify and quantify kissing bond defects in CFRP-Al single lap shear joints. DIC results demonstrated changes in the normal strain (εyy) contour map of the contaminated specimens at relatively lower load levels (15% ~ 30% of failure loads). Kissing bond regions were characterized by negative strains, and these were attributed to high compressive bending strains and the localized disbonding taking placed at the bondline interface as a result of the load application. It was also observed that contaminated samples suffered from more compressive strains (εyy) compared to the baseline sample along the loading direction and they suffered from less compressive strains (εxx) compared to the baseline sample perpendicular to the loading direction. This demonstrated the adverse effect of the kissing bond on the adhesive joint integrity. This was a very significant finding for the reason that hybrid ultrasonic DIC is being developed as a faster, more efficient, and more reliable NDE technique for determining bond quality and predicting bond shear strength in adhesively bonded structures.
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Vullaganti, Anoop. "Mechanical Parameter Characterization of Thin Polymer Films Using Digital Image Correlation." Thesis, Blekinge Tekniska Högskola, Institutionen för maskinteknik, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:bth-21653.
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Mechanical parameter characterization of very thin polymer films using digital im- age correlation is performed in this work. At present days DIC is widely used in the construction, food industries, and aviation. Despite advantages when compared to other conventional methods, but users still face difficulties with the analysis of thin polymers like low-density polyethylene (LDPE) and polyethylene terephthalate (PET) thin polymer films. For the application of sprays to obtain the best pattern quality as well as the potential of thin-film material properties tempering from the stochastic pattern paint. This research work will investigate the effect of several spray paints on the material response of thin polymer film. It also shows how to achieve good surface traction, time effect, and the type of spray to be used for DIC analysis. Finally, this research also studies how the width of the specimen affects the wrinkling effect, which is a common phenomenon while testing the thin polymer films and exhibits the appropriate width for reducing wrinkles on thin polymer films.
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vechalapu, uday bhaskar. "Real-Time 2D Digital Image Correlation to Measure Surface Deformation on Graphics Processing Unit using CUDA C." University of Akron / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=akron1522108261138081.
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Kováříková, Sabina. "Využití DIC při měření zbytkových napětí metodou vrtání otvoru." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2020. http://www.nusl.cz/ntk/nusl-418191.
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This thesis deals with measurement of residual stress by hole drilling method. This method is based on drilling a hole and measurement of deformation in the area around this hole. Measured deformations are then converted to residual stresses by using calibration coefficients. The deformation around the drilled hole is measured by optical non contact method called digital image correlation (DIC). First part of the thesis is focused on current state of research. The thesis contains evaluation of residual stresses by using different methods and evaluation of used methods.
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Palsson, Einar, and Mårten Hansson. "Press Measurements and Virtual Rework of Stamping Dies." Thesis, Blekinge Tekniska Högskola, Institutionen för maskinteknik, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:bth-14918.
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Stamping dies are used in the Sheet Metal Forming (SMF) process for manufacturing of car body parts. The lead time for design and manufacturing of a stamping die is long, and therefore costly. In the final step of the manufacturing process, manual rework is performed to reach a desired pressure distribution on the forming surfaces in order to achieve a robust process and an approved part within tolerance. The main purpose for this work is to study and further develop a Virtual Rework Method that alters the shape of the forming surfaces of a die to compensate for the displacements of a stamping press that occur during stamping. Measurements were performed to obtain the displacements that occur in the stamping press during stamping. These measurements were performed on a double action deep drawing press of the brand Danly, located at Volvo Cars Tool & Die department in Olofström, Sweden. The measurement yields information of how the stamping press is deflecting and deforming during operation. The measurements are recorded with a Digital Image Correlation (DIC) system that records the displacements of the press during stamping. The displacements obtained in the measurements are then used as constraints to inverse FE- model a press table with topology optimization. This optimized press table is used in the Virtual Rework Method to be able to simulate both the deformations of the press and the internal deformations that occur in the die. Pre-simulations were performed before the measurements to ensure that the blank holder plate used in the measurements would withstand the applied blank holder force. These simulations also yield if the displacements were large enough for the ARAMIS DIC system to capture. The FE-model used in this work consisted of a die, blank holder, blank holder plate, outer ram and the optimized press table. The Virtual Rework Method was applied on the FE-model, where the result concludes that the altered shape of the deformed forming surfaces is almost identical to the shape of the nominal forming surfaces. However, an inversed modelled structure that represents the behavior of the outer ram is required to apply the Virtual Rework Method on the blank holder. This inversed modelled structure could be created from the displacements obtained in the measurements. To apply the Virtual Rework method on the punch, further measurements are required, where the position of the ARAMIS DIC system is altered, or an additional ARAMIS DIC system is used.<br>Pressverktyg används i plåtformningsprocessen vid tillverkning av karossdelar. Ledtiden för konstruktion och tillverkning av ett pressverktyg är lång och därför kostsam. I det sista steget i tillverkningsprocessen utförs manuell bearbetning för att nå en önskad tryckfördelning på formningsytorna, vilket ger en robust process och en godkänd del inom toleranserna. Huvudsyftet med detta arbetet är att studera och vidareutveckla en virtuell fläckningsmetod som korrigerar formningsytorna på dynan för att kompensera för de förskjutningar som uppstår i en stämplingspress under stämpling. Mätningar har utfördes för att erhålla förskjutning som uppstår i en stämplingspress under stämpling. Dessa mätningar utfördes på en dubbelverkande djupdragningspress av märket Danly, som finns hos Volvo Cars Tool & Die avdelning i Olofström, Sverige. Mätningen gav information om hur pressen deformeras under stämpling. Mätningarna registreras med ett Digital Image Correlation (DIC) system som registrerar pressens förskjutningar under stämpling. Förskjutningarna som erhållits i mätningarna användes sedan som randvillkor för en inversmodell för topologioptimering av ett pressbord. Detta optimerade pressbord används sedan i den Virtuella fläckningsmetoden för att kunna simulera både pressens stelkroppsrörelse och de interna deformationer som uppstår i pressverktyget. En förstudie utfördes innan mätningarna för att säkerställa att den plåthållarplattan som användes i mätningarna skulle motstå den applicerade plåthållarkraften. Denna förstudie gjordes även för att säkerhetsställa att förskjutningarna som uppstår i plåthållarplattan var stora nog för att ARAMIS DIC systemet skulle registrera dem. FE-modellerna som användes i detta arbete bestod av en dyna, plåthållare, plåthållarplatta, yttre slid och det optimerade pressbordet. Den Virtuella fläckningsmetoden applicerades på FE- modellen, där resultatet gav slutsatsen att den korrigerade formningsytan med applicerad belastning är nästintill identisk med formen på den nominella formningsytan. En inversmodellerad struktur som representerar beteendet hos den yttre sliden krävs emellertid för att tillämpa den Virtuella fläckningsmetoden på plåthållaren. Denna inversmodellerade struktur kunde erhållas från de förskjutning som erhölls i mätningarna. För att tillämpa den Virtuella fläckningsmetoden på stansen krävs ytterligare mätningar, där ARAMIS DIC systemets position ändras eller ett ytterligare ARAMIS DIC system används.<br>Reduced Lead Time through Advanced Die Structure Analysis - Vinnova
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Farolfi, Marco. "Studio e validazione di un sistema tridimensionale per misura di deformazione mediante correlazione di immagini." Bachelor's thesis, Alma Mater Studiorum - Università di Bologna, 2019.
Find full textAbstract:
Questo elaborato tratta l’applicabilità della Digital Image Correlation tridimensionale (DIC 3D) in seguito all’acquisto, da parte dell’Università di Bologna, di due fotocamere Basler a distorsione nulla.
Per utilizzare le due fotocamere è stato scelto di processare le immagini con MultiDIC, un software opensource sviluppato su MATLAB, e per valutare la correttezza dell’analisi sono stati confrontati i valori di deformazione con quelli di un’analisi ad elementi finiti.
Obiettivo di questa tesi è studiare il funzionamento della tecnica e validare un sistema di misura, che possa misurare deformazioni, tensioni e spostamenti senza contatto, in modo da poter essere un’alternativa alle tecniche tradizionali.
Si vuole inoltre presentare una linea guida per eseguire il programma e discutere le principali problematiche incontrate durante le prove sperimentali.
Books on the topic "Digital correlation of images (DIC)"
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Advances in Digital Image Correlation (DIC). MDPI, 2020. http://dx.doi.org/10.3390/books978-3-03928-515-0.
Full textBook chapters on the topic "Digital correlation of images (DIC)"
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Michael A., Michael A., Jean-José Orteu, and Hubert W. Schreier. "Digital Image Correlation (DIC)." In Image Correlation for Shape, Motion and Deformation Measurements. Springer US, 2009. http://dx.doi.org/10.1007/978-0-387-78747-3_5.
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Gdoutos, Emmanuel E. "Digital Image Correlation (DIC)." In Solid Mechanics and Its Applications. Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-030-89466-5_12.
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Blaysat, Benoît, Michel Grédiac, and Frédéric Sur. "Assessing the Metrological Performance of DIC Applied on RGB Images." In International Digital Imaging Correlation Society. Springer International Publishing, 2017. http://dx.doi.org/10.1007/978-3-319-51439-0_26.
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Poozesh, Peyman, Aral Sarrafi, Christopher Niezrecki, Zhu Mao, and Peter Avitabile. "Extracting High Frequency Operating Shapes from 3D DIC Measurements and Phased-Based Motion Magnified Images." In International Digital Imaging Correlation Society. Springer International Publishing, 2017. http://dx.doi.org/10.1007/978-3-319-51439-0_20.
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Robert, Laurent. "Estimation of Digital Image Correlation (DIC) Performances." In Experimental Analysis of Nano and Engineering Materials and Structures. Springer Netherlands, 2007. http://dx.doi.org/10.1007/978-1-4020-6239-1_172.
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Manzato, S., E. Di Lorenzo, and P. Mäckel. "Enhancing Standard GVT Measurements with Digital Image Correlation." In Structural Health Monitoring, Photogrammetry & DIC, Volume 6. Springer International Publishing, 2018. http://dx.doi.org/10.1007/978-3-319-74476-6_5.
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Tran, Jason, and Jayant Sirohi. "Implementation of Piezoelectric Shape Sensors Using Digital Image Correlation." In Structural Health Monitoring, Photogrammetry & DIC, Volume 6. Springer International Publishing, 2018. http://dx.doi.org/10.1007/978-3-319-74476-6_18.
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Connolly, Kevin B., and W. Carter Ralph. "Speckling and Testing with DIC at Microscales." In Advancement of Optical Methods & Digital Image Correlation in Experimental Mechanics. Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-030-59773-3_8.
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Sakaue, Kenichi, and Sho Higuchi. "DIC Measurement of Anisotropy for Plastically Deformed Thermoplastic." In Advancement of Optical Methods & Digital Image Correlation in Experimental Mechanics. Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-030-59773-3_13.
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Passieux, Jean-Charles, Robin Bouclier, and Jean-Noël Périé. "DD-DIC: A Parallel Finite Element Based Digital Image Correlation Solver." In Advancement of Optical Methods in Experimental Mechanics, Volume 3. Springer International Publishing, 2016. http://dx.doi.org/10.1007/978-3-319-41600-7_6.
Full textConference papers on the topic "Digital correlation of images (DIC)"
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Creusen, F. M., E. P. Carton, E. E. van Zeijl, M. Vozarova, and E. Neubauer. "Two Ballistic Test Methods Combined; Residual Energy Method and Digital Image Correlation (REM/DIC)." In Personal Armour Systems Symposium. Royal Military Academy (Belgium), 2023. https://doi.org/10.52202/080042-0032.
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Chu, Wei, Joseph Fu, and Theodore Vorburger. "An Improved Digital Image Correlation Method Applied to Scanning Probe Microscope Images." In ASME 2009 International Manufacturing Science and Engineering Conference. ASMEDC, 2009. http://dx.doi.org/10.1115/msec2009-84274.
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Digital image correlation (DIC) is a method for measuring the surface displacements and displacement gradients in materials under deformation. The method has also been applied to the calculation of image distortion for scanning probe microscopy (SPM). The traditional DIC method directly uses the intensity values of compared images but does not take out-of-plane nonlinearity error into account. However, in SPM measurements, the recorded z-direction value is a sum of the real surface height of the sample and any longitudinal deformation of the piezoelectric tube. In order to improve the calculation accuracy of the displacement fields, an improved DIC method is performed here. Two new parameters related to out-of-plane error are introduced in the mathematical modeling. The in-plane displacements between two compared images are then calculated pixel by pixel, with the z-direction error accounted for. This method is tested by applying it to two pairs of atomic force microscopy (AFM) images along the fast and slow scan directions.
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Montgomery, Veronica, Oscar Martinez, Paul Nogradi, Lance Lowe, and Abiodun Adeniyi. "Free Drop Impact Data Acquisition Using Digital Image Correlation." In ASME 2023 Pressure Vessels & Piping Conference. American Society of Mechanical Engineers, 2023. http://dx.doi.org/10.1115/pvp2023-106649.
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Abstract Radioactive materials are widespread throughout our everyday activities and are used in many different types of industries. There are about 3 million shipments of radioactive materials that occur each year in the United States. Because radioactive materials are so widespread, safety and security are top priorities for the Package Testing Program (PTP) at Oak Ridge National Laboratory (ORNL), and effective and accurate data collection methods are imperative. The packaging used to carry nuclear materials is subjected to rigorous tests to verify its durability. One such test is the free-drop test. Impact data are often collected through an accelerometer attached to the test unit. Unfortunately, these devices are easily broken in the testing environment and are expensive to procure, install, and post process. Digital image correlation (DIC) using high-speed images offers a non-contact alternative. DIC is an optical method that employs image registration techniques to accurately measure changes in images. To verify the suitability of the cameras and process, a test weight was dropped from various heights, and the impact acceleration was derived using DIC. This paper compares the results with data from the attached accelerometer. A total of nine drop tests were performed with three different image capture rates (frames per second) and from three different package drop heights. An ANSYS LS-Dyna model was also used to determine theoretically predicted deceleration rates for comparison with the DIC and accelerometer data.
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Sia, Bernard. "USE OF CORROSION PRODUCT FOR DIGITAL IMAGE CORRELATION MEASUREMENTS." In 2024 NDIA Michigan Chapter Ground Vehicle Systems Engineering and Technology Symposium. National Defense Industrial Association, 2024. http://dx.doi.org/10.4271/2024-01-3733.
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<title>ABSTRACT</title> <p>This paper describes the results of work performed to assess the use of corrosion product for Digital Image Correlation (DIC) measurements. DIC was recently evaluated for its capability to measure contour, strain and deflection of metals using the corrosion product instead of a painted speckle pattern. The DIC system, consisting of two cameras with zoom lenses, was set up at an angle to the specimen, enabling both cameras to image multiple sides of a specimen simultaneously. This provides a more direct measurement of in-plane and out-of-plane deformation and strains. Aluminum and steel dogbones were placed in a salt spray chamber for up to 10 days. Contour measurements were then taken at various evaluation settings as an initial assessment of the use of the corrosion product for DIC measurements. Multiple tensile tests were then performed to assess the capability of using corrosion product for strain and deflection measurements while a material is under applied load. System bias and deviation was determined using static images taken of the corroded dogbones. Test results and analysis are presented in detail in this paper, as well as conclusions drawn as a result of these tests.</p>
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Jin, Helena (Huiqing), Wei-Yang Lu, Jeff Chames, and Nancy Yang. "Characterization of LIGA Microsystems Using Digital Image Correlation Technique and SEM Imaging." In ASME 2005 International Mechanical Engineering Congress and Exposition. ASMEDC, 2005. http://dx.doi.org/10.1115/imece2005-81123.
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A new experimental technique was developed to characterize the mechanical properties of LIGA (an acronym from German words for lithography, electroplating, and molding) materials. An advanced imaging capability, scanning electron microscopy (SEM), with an integrated loading stage allows the acquisition of in situ microstructural images at the micro scale during loading. The load is measured directly from a load cell, and the displacement field is calculated from the SEM images based on the digital image correlation (DIC) technique. The DIC technique is a full-field deformation measurement technique which obtains displacement fields by comparing random speckle patterns on the specimen surface before and after deformation. The random speckle patterns are typically generated by applying a thin layer of material with high contrast to a specimen surface. Alternatively, DIC can also be applied using the microstructural features of a surface as texture patterns for correlation. DIC technique is ideally suited to characterize the deformation field of MEMS structures without the need to generate a random speckle pattern, which can be very challenging on the micro and nanoscale. In this paper, the technique is experimentally demonstrated on a LIGA specimen. The digital images showing LIGA surface features acquired during the loading can serve as random patterns for the DIC method. Therefore, full-field displacement and strain can be obtained directly on the specimen and the errors incurred by the testing system can be eliminated.
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Goh, Ching Pang, and Mani Maran Ratnam. "Scanner-Based Digital Image Correlation Method for Mechanical Characterization of Rubber." In International Conference on Digital Transformation and Applications (ICDXA 2020). Tunku Abdul Rahman University College, 2020. http://dx.doi.org/10.56453/icdxa.2020.1009.
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The digital image correlation (DIC) method coupled with a moveable camera has been widely used for large in-plane displacement measurement in elastomeric materials. However, this method has the limitation due to the limited field-of-view (FOV) of the camera. In this paper, a novel scanner based digital image correlation (SBDIC) method which enables acquisition of a large FOV of speckle pattern image on the specimen has been developed. The entire information of the deformation was obtained and analyzed up to 350% strain. The correlation between the images at successive stages was computed using incremental cross correlation (CC) tracking algorithm. The Young’s modulus and Poisson’s ratio of vulcanized natural rubber (VNR) up to 350% axial strain were determined simultaneously using the same set of data. Tangent and secant modulus of the rubber at axial strains of 50% to 350% in 50% increments obtained from the scanner-based DIC method was compared with those obtained from a universal tensile test machine (UTM). In addition, the Poisson’s ratios show that the experimental data fitted well with the theoretical result up to an axial stretch ratio of 2.0. The SBDIC method was found to be a potential tool for low cost measurement of mechanical characteristics of polymeric materials. Keywords: DIC, large deformation, cross-correlation, axial strain, Poisson ratio
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Shoop, S., A. Sopher, J. Stanley, T. Botha, C. Becker, and S. Ells. "DIGITAL IMAGE CORRELATION FOR OFF-ROAD MOBILITY." In 2024 NDIA Michigan Chapter Ground Vehicle Systems Engineering and Technology Symposium. National Defense Industrial Association, 2024. http://dx.doi.org/10.4271/2024-01-3615.
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<title>ABSTRACT</title> <p>Digital Image Correlation (DIC) technology developed for off-road vehicle dynamics at the University of Pretoria, South Africa, was recently assessed for all-season and all-terrain viability through a Foreign Technology Assessment Support (FTAS) program at the US Army Engineer Research and Development Center-Cold Regions Research and Engineering Laboratory (ERDC-CRREL) in Hanover, New Hampshire (NH). Advancements in camera technology have brought on the proliferation of inexpensive, high resolution and high frame-rate cameras. At the same time the increase in computational power of computers has allowed algorithms to determine the depth of a scene and enable the near real-time tracking of features on an image. These advancements have enabled the application of DIC to measure surface and velocity profiles as well as deformation from a reference state (for terrain or for tires). In large off-road vehicle dynamics DIC can be used to improve maneuverability of vehicles by monitoring the road or terrain surface before and after the tire passes. From these measurements the initial road roughness and the deformation of the terrain can be determined to provide an indication of the terrain trafficability. DIC can also be used to determine the motion of the vehicle or tire, which can aid in vehicle safety systems via slip angle and traction performance.</p> <p>This paper details the application of DIC on a military vehicle to measure terrain deformation and vehicle motion on varied terrain with the final aim of providing additional information to the driver or vehicle control system for performance optimization; and ultimately for providing feedback on mobility or terrain information for situational awareness at the driver or theater level. The technology was tested and validated using the CRREL Instrumented Vehicle (CIV) and two military vehicles; an unarmored High Mobility Multipurpose Wheeled Vehicle (HMMWV) (M1097) and a 20-ton Heavy Expanded Mobility Tactical Truck (HEMTT). Testing with the HEMTT on snow, ice, water, asphalt, concrete and vegetated ground will be shown to illustrate use of the technology on large military vehicles on a variety or surfaces.</p>
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Hieb, Fritz, and Michael Hargather. "A Low-Cost and Simplified Digital Image Correlation Software Package for Use in Undergraduate Teaching Laboratories." In ASME 2016 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2016. http://dx.doi.org/10.1115/imece2016-67620.
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Digital image correlation (DIC) has become an industry staple quickly replacing classic techniques. High-speed images are taken of a material sample being deformed, then algorithms applied to calculate variables of sample deformation such as stress, strain, displacement and displacement velocity. Currently, the analysis technology is not available at the level of simplicity and accessibility needed to teach the methods in an undergraduate laboratory. This project aims to develop a single program to perform DIC that is simple to use, accurate, and available at low cost. This paper describes the state of current DIC algorithm research, drawbacks of available technologies, the development cycle of the software including the techniques used to obtain the necessary accuracy and performance, and a demonstration of the DIC functionality in comparison to results obtained from commercial software.
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Guo, Bicheng, Xiaowan Zheng, Siyuan Fang, and Lianxiang Yang. "Suction Cup Quality Predication by Digital Image Correlation." In WCX SAE World Congress Experience. SAE International, 2023. http://dx.doi.org/10.4271/2023-01-0067.
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<div class="section abstract"><div class="htmlview paragraph">Vacuum suction cups are used as transforming handles in stamping lines, which are essential in developing automation and mechanization. However, the vacuum suction cup will crack due to fatigue or long-term operation or installation angle, which directly affects production productivity and safety. The better design will help increase the cups' service life. If the location of stress concentration can be predicted, this can prevent the occurrence of cracks in advance and effectively increase the service life. However, the traditional strain measurement technology cannot meet the requirements of tracking large-field stains and precise point tracking simultaneously in the same area, especially for stacking or narrow parts of the suction cups. The application must allow multiple measurements of hidden component strain information in different fields of view, which would add cost. In this study, a unique multi-camera three-dimensional digital image correlation (3D-DIC) system was designed and applied to measure the strain concentration of the suction cups while the cups were running the pulling progress. In this technique, a multiplexed quad-cameras DIC system which contains two sets of 3D-DIC system (4 cameras) with different field of view or different measurement directions enables simultaneous measurement of full-filed and hidden parts under the same calibration progress. The first two cameras built a sub-group of the 3D-DIC system, which was used to measure the local strain of the narrow or stacked prats. The other system was used to acquire the strain fields of the entire suction cup. In addition to the experimental test, the fatigue test to see the cracks appeared location. The results of DIC were compared to the fatigue data, and the DIC experimental data validated the crack location. This project aims to help designers and operators thoroughly understand the performance of vacuum cups by investigating the strain concentration and crack location.</div></div>
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Jin, Helena (Huiqing), Wei-Yang Lu, Simon Scheffel, Michael K. Neilsen, and Terry D. Hinnerichs. "Characterization of Mechanical Behavior of Polyurethane Foams Using Digital Image Correlation." In ASME 2005 International Mechanical Engineering Congress and Exposition. ASMEDC, 2005. http://dx.doi.org/10.1115/imece2005-81115.
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Polyurethane foams have good energy absorption properties and are effective in protecting sensitive components from damages due to impact. The foam absorbs impact energy by crushing cells and undergoing large deformation. The complex deformation of the foam needs to be modeled accurately to simulate the impact events. In this paper, the Digital Image Correlation (DIC) technique was implemented to obtain the deformation field of foam specimens under compression tests. Images of foam specimen were continuously acquired using high-speed cameras. The full field displacement and strain at each incremental step of loading were calculated from these images. The closed-cell polyurethane foam used in this investigation was nominal 0.32 kg/m^3 (20 pcf). In the first experiment, cubic specimens were compressed uniaxially up to 60%. The full-field displacements and strains obtained using the DIC technique provide detailed information about the inhomogeneous deformation over the area of interest during loading. In the second experiment, compression tests were conducted for a simple foam structure - cubic foam specimens with a steel cylinder inclusion. The strain concentration at the interface between steel cylinder and foam was studied to simulate the deformation of foam in a typical application. In the third experiment, the foam was loaded from the steel cylinder during the compression. The strain concentration at the interface and the displacement distribution over the surface were compared for cases with and without a confinement fixture to study the effects of confinement. These experimental results demonstrate that the DIC technique can be applied to polyurethane foams to study the heterogeneous deformation. The experimental data is briefly compared with the results from modeling and simulation using a viscoplastic model for the foam.
Reports on the topic "Digital correlation of images (DIC)"
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Justusson, Brian P., David M. Spagnuolo, and Jian H. Yu. Assessing the Applicability of Digital Image Correlation (DIC) Technique in Tensile Testing of Fabric Composites. Defense Technical Information Center, 2013. http://dx.doi.org/10.21236/ada571047.
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Tire Experimental Characterization Using Contactless Measurement Methods. SAE International, 2021. http://dx.doi.org/10.4271/2021-01-1114.
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In the frame of automotive Noise Vibration and Harshness (NVH) evaluation, inner cabin noise is among the most important indicators. The main noise contributors can be identified in engine, suspensions, tires, powertrain, brake system, etc. With the advent of E-vehicles and the consequent absence of the Internal Combustion Engine (ICE), tire/road noise has gained more importance, particularly at mid-speed driving and in the spectrum up to 300 Hz. At the state of the art, the identification and characterization of Noise and Vibration sources rely on pointwise sensors (microphones, accelerometers, strain gauges). Optical methods such as Digital Image Correlation (DIC) and Laser Doppler Vibrometer (LDV) have recently received special attention in the NVH field because they can be used to obtain full-field measurements. Moreover, these same techniques could also allow to characterize the tire behavior in operating conditions, which would be practically impossible to derive with standard techniques. In this paper we will demonstrate how non-contact full-field measurement techniques can be used to reliably and robustly characterize the tire behavior up to 300 Hz, focusing on static conditions. Experimental modal analysis will extract the modal characteristic of the tire in both free-free and statically preloaded boundary conditions, using both DIC and LDV. The extracted natural frequencies, damping ratios and full-field mode shapes will be used on one side to improve the accuracy of tire models (either by deriving FRF based models or updating FE ones) but also as a reference for future investigation on the tire behavior characterization in rotating conditions.
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Comparison of mechanical behavior between longitudinal lap-welded joints and transverse fillet welded joints of high strength steel. The Hong Kong Institute of Steel Construction, 2022. http://dx.doi.org/10.18057/icass2020.p.302.
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Mechanical behavior of twenty-eight longitudinal lap-welded joints made of high strength steels (HSS) under tension load was investigated by experimental study. Weaknesses due to traditional deformation measurements for fillet welded joints can be perfectly solved by digital image correlation techniques (DIC). The effect of parameters (e.g. weld size, weld length and mismatch ratio) on mechanical properties (e.g. ultimate strength, failure modes, weld ductility and fracture angle) of longitudinal fillet welds and transverse fillet welds, which was introduced in detail in previous work by the authors, were compared. Generally, because of the difference on the combination of shear force and tension force, the fracture angle of longitudinal welded specimens (around 50) were much more divergent from transverse welded specimens (around 20) even though both of them failed at welded zone (welded zone only refers to weld metal in this paper), resulting that the mean strength of longitudinal welded specimens were only 0.58 time of transverse welded specimens. Conversely, the mean deformation capacity of longitudinal welded specimens was almost 4.0 times of transverse welded specimens. Moreover, it was confirmed that the predicted loads of EC3 and AISC Specification were close and slightly conservative for all specimens.