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Showing papers on "Photoelasticity published in 2021"


Journal ArticleDOI
TL;DR: The aim of this study is to evaluate the stresses transferred to peri-implant areas from single implants restored with different restorative materials and subjected to a static vertical load with low eccentricity.
Abstract: The aim of this study is to evaluate the stresses transferred to peri-implant areas from single implants restored with different restorative materials and subjected to a static vertical load with low eccentricity. A total of 12 crowns were made with four types of materials: carbon fiber-composite, metal-ceramic, metal-composite, and full-metal, all of them cemented over a titanium abutment. Three different ways of approaching the problem have been used independently to verify the robustness of the conclusions. The experimental results of stress distribution around the implant were obtained by two image processing techniques: Digital Photoelasticity and Digital Image Correlation (DIC). The tests have been modelled by 3D Finite Element Method (FEM). The FEM models have also been used to study the sensitivity of the results to slight changes in geometry or loads, so that the robustness of the experimental techniques can be analyzed. In addition, the realistic bone morphology of the mandible has also been modelled by FEM, including the cortical and trabecular bone property distinctions.

14 citations


Journal ArticleDOI
Tadashi Inoue1
22 Apr 2021
TL;DR: In this paper, the molecular interpretation of strain-induced birefringence for amorphous polymers over a wide time/temperature region is briefly reviewed and compared.
Abstract: Recent progress on the molecular interpretation of strain-induced birefringence for amorphous polymers over a wide time/temperature region is briefly reviewed. In the rubbery region, orientational ...

10 citations


Journal ArticleDOI
TL;DR: In this article, the authors revisited Treloar's and Arruda's models of nonlinear photoelasticity for rubber-like materials and built an experimental setup to measure the birefringence of PDMS samples as a function of stress/stretch.
Abstract: Photoelasticity often refers to the birefringence effect of materials induced by elastic deformation. Recently, many experiments on the photoelasticity of soft materials have been reported. However, the experimental results are mainly qualitative observations and lack any theoretical analysis. In this paper, we revisit Treloar's and Arruda's models of nonlinear photoelasticity for rubber-like materials. Both models establish the intrinsic relationship between stretch and birefringence, based on the statistics of chain polarizability and a network theory. We discuss the difference of the two models and build an experimental setup to measure the birefringence of PDMS samples as a function of stress/stretch. We vary the curing ratio of PDMS to study the effect of chain density on birefringence and compare with Treloar's theory. We further use experimental data of double-network hydrogels in the literature to compare with theory and find that when the deformation is large compared with the limiting stretch of the material, Arruda's model fits the experimental data much better than Treloar's model. This work presents a basis of using the theory of nonlinear photoelasticity to guide the analysis of experiments.

9 citations


Journal ArticleDOI
22 Jan 2021-Irbm
TL;DR: In this paper, the authors evaluated and compared the stress distribution and primary stability of three different designs of Neodent® dental implants and found that G1 and G2 exhibit high primary stability and satisfactory stress distribution.
Abstract: Objectives This study aimed to evaluate and compare the stress distribution and primary stability of three different designs of dental implants. Material and Methods 24 implants Neodent® were used ( n = 8 ): G1 – Alvim CM; G2 – Drive CM; G3 – Facility, submitted to insertion torque (IT) and pullout test, on 20 PCF (0.24 g/cm3) and 40 PCF (0.64 g/cm3) polyurethane blocks. For the stress distribution, by means of photoelasticity, axial and oblique loads (model at 30° inclination) of 100 N were performed, for reading and quantifying the fringe orders. According to the distribution data, a parametric or non-parametric analysis was performed ( α = 0.05 ). Results The IT was lower in G3 ( p 0.05 ) compared to G1 and G2, in 20 and 40 PCF polyurethanes. In the pullout, no difference ( p > 0.05 ) was observed between G1 and G2, in both 20 and 40 PCF polyurethanes. In the comparisons between polyurethanes, higher values ( p 0.05 ) were obtained in the 40 PCF for IT and pullout. In the axial loading, lower stresses were observed in the cervical third and higher stresses in the middle and apical third of the implants. With the oblique inclination of the models, higher stresses were generated in the opposite side of the load, in the cervical third of G1, followed by G3 and G2. Conclusion The results allow to affirm that G1 and G2 exhibit high primary stability and satisfactory stress distribution. Although G3 generates stresses comparable to other implants, its indication is limited in low density bones.

6 citations


Journal ArticleDOI
TL;DR: In this paper, an experimental and numerical model was proposed to study the creep behavior of the unidirectional Alfa fiber composite strength by the photoelasticity method, which merges between experimental tests and numerical simulation.
Abstract: In this paper, we propose an experimental and numerical model to study the creep behavior of the unidirectional Alfa fiber composite strength by the photoelasticity method. To have better mechanical properties, chemical treatment is made for Alfa fibers. Tensile tests are made to predict the Young modulus and tensile strength. These tests confirm that the chemical treatment during 48 Hours of Alfa fibers collected from the south region gives the best results. After that, specimens are made in Medapoxy STR resin and treated Alfa fibers of the south region. All fibers of specimens are arranged approximately in multiple hexagonal clusters embedded in the matrix. For the micromechanical fiber stress redistribution or load sharing theory to be applied, clusters must minimally contain one broken fiber. Consequently, we have a stress perturbation due to a fiber fracture, which propagates to the nearest-neighbor fibers. This perturbation enables us the photoelastic visualization of the fracture events during the creep tests. The contour diagram and fringe values give us the accurate distribution of stress near broken fibers showing local shear stress concentrations during the time. To simulate the creep response and failure mechanism, the Tsai–Wu failure criterion was applied on ANSYS explicit dynamic software. Because it merges between experimental tests and numerical simulation, the present study offers a real scientific contribution in the creep behavior of biobased composite strength by the photoelasticity method.

6 citations


Proceedings ArticleDOI
13 Jul 2021
TL;DR: In this paper, the coefficients of the Williams series expansion in the vicinity of two interacting cracks or notches were determined experimentally and computationally using the over-deterministic method.
Abstract: The purpose of this work is to determine experimentally and computationally the coefficients of the Williams series expansion in the vicinity of two interacting cracks or notches. In this study, the multi-parameter description of the crack-tip fields for digital processing of the experimental data obtained from photoelastic experiments is complied. The special programming tool for digital processing of the experimental data is elaborated. The Williams expansion is introduced for approximation of the stress/displacement distribution. The over-deterministic method is used for calculation of the coefficients of the power series terms because it requires only a conventional FE analysis. Results determined via finite element analysis are compared to those calculated by means of the stress distribution expressed via the Williams expansion under consideration of various numbers of initial terms of the series. It is shown that the higher-order terms of the Williams expansion can be significant when the extent of the isochromatic fringe is far enough in comparison to the crack length. It is shown that the use of higher order terms leads to increase of the domain where the Williams series expansion can be used.

5 citations


Journal ArticleDOI
TL;DR: In this paper, a method incorporating photoelasticity and DIC techniques was developed to determine the stress and strain fields simultaneously in different porous structures which were fabricated by three-dimensional (3D) printed technique.

5 citations


Proceedings ArticleDOI
01 Aug 2021
TL;DR: This new computational hybrid approach calculates the stress field by extract the phase steps from RGB color channels of a photoelastic color image by integrated the load stepping strategy with a computational hybrid phase algorithm, hence only bright field images are required.
Abstract: Digital photoelasticity is used for evaluating the stress in loaded bodies. However, when dynamic analyses are needed, the motions of optical elements are an experimental challenge. This new computational hybrid approach calculates the stress field by extract the phase steps from RGB color channels of a photoelastic color image. Our approach integrated the load stepping strategy with a computational hybrid phase algorithm, hence only bright field images are required. Although, our method has a lower performance than phase shifting methods evaluated, the principal advantage of this hybrid strategy is that only a color- image is required to analyze stress field, avoided capture multiple images for analyzing phase maps.

4 citations


Journal ArticleDOI
TL;DR: In this article, the authors present the measurement of residual stress distribution in ITER (The Way" in Latin) diagnostics windows using a circular polariscope, which is based on measurement of the change in the state of polarization of a circularly polarized light after transmission/reflection from the stressed window under test.
Abstract: This article presents the measurement of residual stress distribution in ITER (“The Way” in Latin) diagnostics windows using a circular polariscope. The method being used is based on the measurement of the change in the state of polarization of a circularly polarized light after transmission/reflection from the stressed window under test. The theory based on Mueller calculus for the experimental setup has been presented. The measurement technique is validated for transmission mode by comparing the stress values measured for borosilicate glass (BK7) sample disks under diametrical compression with the theoretical values obtained using linear isotropic theory of elasticity. The method is, then, applied to an undamaged and a damaged ITER trial window, both in transmission and reflection modes, to observe the stress patterns inside the glass material and on the glass to metal seal. The major observations are that the undamaged window shows higher stress in majority of the cross section with lower stress values at localized regions. The glass near the seal shows high values of stress all along the circumference in case of the undamaged window. The damaged window that has got detached from the metal seal shows much lower stress values in majority of the cross section of the window with higher stress values in some regions. The region where the seal seems to have got detached from the glass shows lower values of stress at the seal location, and also the stress values in the glass near those locations are low. In conclusion, by observing the stress patterns inside the window, this technique helps determine the health of vacuum seal, and hence can be used in taking preventive measures.

4 citations


Journal ArticleDOI
TL;DR: In this paper, a reflection polariscope system with a high-temperature loading chamber was designed to freeze and capture the stress fringes in the printed model, and the effects of continuous temperature rise and loading during the frozen stress tests on the stress birefringence of the thermo-sensitive photopolymers were investigated.

3 citations



Journal ArticleDOI
18 Apr 2021-Optik
TL;DR: In this article, an application of reflection photoelasticity used to analyze stressed samples was presented, which showed isochromatic and isoclinic fringe patterns in a poly(methyl methacrylate) sample.

Journal ArticleDOI
TL;DR: In this paper, an automatic algorithm for the complete identification of the crack tip location was proposed, where the first hypersingular functions (i.e., the 1st negative term of William's series) were used to estimate the crack orientation.

Journal ArticleDOI
TL;DR: In this article, the dispersion dependence of the birefringence of a pure 6CHBT liquid crystal sample at a constant temperature was investigated in the wavelength range of (400-800) nm and (900-1800) nm.

Journal ArticleDOI
TL;DR: In this paper, the authors developed transparent homogeneous FGMs with similar theoretical and physical properties and proposed a method for determining their stress intensity factors (SIFs) and T-stresses via photoelastic experiments.
Abstract: To analyze the stress of functionally graded materials (FGMs) through an experiment, transparent homogeneous FGMs (THFGMs) with similar theoretical and physical properties need to be created. This study developed such THFGMs and proposed a method for determining their stress intensity factors (SIFs) and T-stresses via photoelastic experiments. The Young’s modulus and Poisson’s ratio of these THFGMs linearly change along the physical variation direction, and the shear modulus varies almost linearly. The SIFs and T-stresses were obtained for the central and edge cracks in finite rectangular FGM plates with linear variations in the shear modulus under constant density along the direction of the crack under mode I loading. The SIFs and T-stresses can be obtained using the exponential and linear variation in the stress fields, even if the physical properties of FGM plates show linear variation in the shear modulus. The characteristics of the experimental SIFs obtained in this study generally agree with those of theoretical SIFs reported in previous research. For center crack tips, the SIFs at the hard right crack tip were greater than those at the soft left crack tip. For edge crack tips, when a/W 0.35, the SIFs were greater than the homogeneous materials. The experimental T-stresses for the center crack agreed well with the numerical T-stresses reported in previous research. For the edge crack, when a/W ≤ 0.3, the experimental T-stresses agreed with the numerical T-stress, but when a/W ≥ 0.4, considerable differences were observed between the experimental and numerical T-stresses. Where a(a) denotes the crack length for edge cracks or half the crack length for center cracks, and W is the width of the specimen. Experimental results coincide well with those reported in the literature, except for the T-stresses for edge crack when a/W > 0.3. Therefore, the THFGMs, which are new FGMs developed in this study, can be effectively used in experimental fracture analysis.

Journal ArticleDOI
TL;DR: In this paper, a novel use of digital light processing (DLP), a form of vat polymerization AM technologies in photoelastic specimen production, is discussed in detail.
Abstract: Material behavior modeling for additive manufacturing (AM) technology represents a challenge because the manufacturing process and post-processing parameters strongly influence the mechanical properties of the part. Photoelasticity is a well-known full-field optical technique used for direct stress/strain determination and design evaluation purposes. A novel use of digital light processing (DLP), a form of vat polymerization AM technologies in photoelastic specimen production is discussed in this paper. A number of preliminary experiments were undertaken to address critical issues related to DLP process. It was concluded that the UV exposure time, dependent mostly on layer thickness, and orientation are the main factors affecting the mechanical properties and the accuracy of the printed samples. Pure bending test was used to determine mechanical and photoelastic properties of a commercially available acrylic-based photopolymer, not previously reported in the literature. The rectangular beam sample used was built in vertical layer orientation and fully-cured. The estimated value of Young’s modulus was within the expected range for acrylics, and the photoelastic constant obtained provides increased confidence in the investigated acrylic polymer for photoelastic stress analysis purposes, and consequently for validation of computer-based models.

Journal ArticleDOI
TL;DR: In this article, a heterodyne polariscope composed of a Zeeman laser, a half-wave plate, two quarter-wave plates, an analyzer, a photo-detector, and an x-y stage is proposed for determining the full-field principal angle and phase retardation of stressed plastic substrates.

Journal ArticleDOI
04 Feb 2021
TL;DR: In this article, optical anisotropy effects in architectural glass are evaluated using digital image processing, and the results of textural features of different glass panes are compared using reference areas and geometry factors.
Abstract: In the present paper, optical anisotropy effects in architectural glass are evaluated using digital image processing. Hereby, thermally toughened glass panes were analyzed quantitatively using a circular polariscope. Glass subjected to externally applied stresses or residual stresses becomes birefringent. Polarized light on birefringent materials causes interference colors (iridescence), referred to as anisotropies, which affect the optical appearance of glass panes in building envelopes. Thermally toughened glass, such as toughened safety glass or heat strengthened glass, show these iridescences due to thermally induced residual stress differences. RGB-photoelastic full-field methods allow the quantitative measurement of anisotropies, since the occurring interference colors are related to the measured retardation values. By calibrating the circular polariscope, retardation images of thermally toughened glass panes are generated from non-directional isochromatic images using computer algorithms. The analysis of the retardation images and the evaluation of the anisotropy quality of the glass is of great interest in order to detect and sort out very low quality glass panes directly in the production process. Therefore, in this paper retardation images are acquired from different thermally toughened glass panes then different image processing methods are presented and applied. It is shown that a general definition of exclusion zones, e.g. near edges is required prior to the evaluation. In parallel, the limitations in the application of first-order statistical and threshold methods are presented. The intend of the investigation is the extension of the texture analysis based on the generation of Grey Level Co-occurrence Matrices, where the spatial arrangement of the retardation values is considered in the evaluation. For the first time, the results of textural features of different glass pane formats could be compared using reference areas and geometry factors. By reduction of the original image size, the computation time of textural analysis algorithms could be remarkably speeded up, while the textural features remained the same. Finally, the knowledge gained from these investigations is used to determine uniform texture features, which also includes the pattern of anisotropy effects in the evaluation of thermally toughened glass. Together with a global evaluation criterion this can now be implemented in commercial anisotropy measurement systems for quality control of tempered architectural glass.

Journal ArticleDOI
01 Feb 2021
TL;DR: In this paper, a photoelastic method for the construction of the multi-point crack-tip series expansions in isotropic elastic semi-disks is employed, and the first ten coefficients in the multipoint series expansion have been ascertained.
Abstract: The digital photoelastic method for the construction of the multi-point crack-tip series expansions in isotropic elastic semi-disks is employed. The series of cracked specimens in the form of the semi-disk with vertical and inclined notches from optically active materials (polycarbonates) were produced and tested under three-point bending. The principal intent of this experimental procedure of the phototelasticity technique was estimation of the amplitude coefficients in the Williams expansion in which the non-singular high-order terms are taken into account. The first ten coefficients in the multi-point series expansion have been ascertained. To retrieve the points belonging to the isochromatic fringe patterns and having the minimum light intensity the digital image processing scheme was utilized. The scheme of the over-deterministic method for evaluation of the amplitude coefficients (fracture mechanics parameters) is applied. Additionally, the problem was reduced to the problem of minimizing the objective function which is the quadratic form for the stress field in terms of unknown fracture mechanics parameters. The finite element analysis for the same series of the notched specimens was performed. The demeanour of the stress field in the neighbourhood of the notch tip for different types of mixed mode loading was elucidated from finite element analysis. The coefficients of the asymptotic presentation of the stress and displacement fields are recovered from finite element results. It is shown that the multi-point coefficients are in good agreement with experimental observations.

Journal ArticleDOI
TL;DR: In this article, a digital image processing tool for experimental data obtained from the photoelasticity experiments is developed and utilized, which is based on the Ramesh approach but allows us to scan the image in any direction and to analyse the image after any number of logical operations.
Abstract: In this work, digital photoelasticity method is appliedfor estimation of the crack tip fracture mechanics parameters for a plate with double edge notches and different crack configurations.The digital image processing tool for experimental data obtained from the photoelasticity experiments is developedand utilized. The digital image processing tool is based on the Ramesh approach but allows us to scan the image in any direction and to analyse the image after any number of logical operations. In the digital image processing fringe analysis, the optical data contained in the transmission photoelasticisochromatics were converted into text file and then the points of isochromatic fringes with minimum light intensity were used for evaluating fracture mechanics parameters. The multi-parameter stress field approximation is used. The mixed mode fracture parameters, especially stress intensity factors (SIF) are estimated for specimen configurations like double edge notches and inclined center crack using the proposed algorithm based on the classical over-deterministic method. The effects of higher-order terms in the Williams expansion were analysed for different cracked specimens. It is shown that the higher order terms are needed for accurate characterization of the stress field in the vicinity of the crack tip. The experimental SIF values estimated using the proposed method are compared with analytical/finite element analysis (FEA) results, and are found to be in good agreement.

Journal ArticleDOI
TL;DR: In this article, the effect of different parameters, such as the stretching rates and ambient temperature on the formation of shear bands is investigated, and the influence of heating pre-existed shear band is studied.
Abstract: In this work, the shear bands formed during the stretching of isotactic polypropylene fibers are studied. The digital photoelasticity technique is applied to provide full-field visualization of the stress of the shear bands regions. The mechanical testing device is modified to be suitable for mechanical measurements. The effect of different parameters, that is, the stretching rates and the ambient temperature on the formation of shear bands is investigated. Finally, the influence of heating pre-existed shear bands is studied. Photoelastic patterns of the shear bands at these conditions are included for illustration.

Journal ArticleDOI
TL;DR: In this paper, a 3D-ILC-based model with internal cracks was presented, and with the aid of the photoelastic test technology, it visually showed the distribution characteristics of the stress field inside the rock with defects under the three-point bending test method.
Abstract: Great achievements have been made regarding the stress field in the two-dimensional state, however the study of three-dimensional stress field visualization has still not been comprehensively examined. The model with internal cracks was prepared by the laser-medium interaction (3D-ILC), and with the aid of the photoelastic test technology, it visually showed the distribution characteristics of the stress field inside the rock with defects under the three-point bending test method. Primarily, based on the two-dimensional and three-dimensional stress optics law, the isometric fringes were converted into phase differences or optical path differences to visualize the stress field. Moreover, transparent glass, which had better transparency and brittleness closer to real rock was selected as the specimen material. Internal cracks changed the stress fringe distribution of the specimen, and the combination of 3D-ILC technology and photoelasticity provided a new way to visualize the three-dimensional stress field of brittle materials with internal cracks. Through the secondary development and utilization of ABAQUS finite element analysis software, the internal stress fields of brittle solid materials with horizontal internal cracks were visualized. Accurate characterization of the three-dimensional stress field of brittle solid materials has been a long-term goal pursued by researchers in the field of fracture, and it is also the basis and key to solving many practical engineering problems such as design, safety analysis and evaluation.

Journal ArticleDOI
TL;DR: The basic principle of stress measurement based on photoelasticity is introduced and the research progress of stress Measurement technologies based on this principle is reviewed, which can be classified into two methods: polarization method and interference method.
Abstract: It is of great significance to measure the residual stress distribution accurately for optical elements and evaluate its influence on the performance of optical instruments in optical imaging, aviation remote sensing, semiconductor manufacturing, and other fields. The stress of optical elements can be closely related to birefringence based on photoelasticity. Thus, the method of quantifying birefringence to obtain the stress becomes the main method of stress measurement technologies for optical elements. This paper first introduces the basic principle of stress measurement based on photoelasticity. Then, the research progress of stress measurement technologies based on this principle is reviewed, which can be classified into two methods: polarization method and interference method. Meanwhile, the advantages and disadvantages of various stress measurement technologies are analyzed and compared. Finally, the developing trend of stress measurement technologies for optical elements is summarized and prospected.

Journal ArticleDOI
TL;DR: In this paper, a femtosecond transient absorption microscopy was applied to study the anisotropic coherent phonon responses, where multiorder phonon harmonics were observed with thickness dependence well explained by the linear chain model, allowing rapid optical mapping of phonon frequency distributions.
Abstract: Coherent longitudinal lattice vibrations of black phosphorus provide unique access to the out-of-plane strain coupled in-plane optical properties. In this work, polarization-resolved femtosecond transient absorption microscopy is applied to study the anisotropic coherent phonon responses. Multiorder phonon harmonics were observed with thickness dependence well explained by the linear chain model, allowing rapid optical mapping of phonon frequency distributions. More interestingly, exotic coherent phonon oscillations occourred with a π-phase jump between the armchair and zigzag polarizations, which reveals opposite signs of photoelasticity under the longitudinal strain. Specifically, compressive strain reduces the imaginary refractive index in the armchair polarization but increases the real refractive index in the zigzag polarization, as confirmed by the ab initio calculations and thin film model. These fundamental properties of black phosphorus hold potential for applications in ultrafast and polarization-sensitive photoacoustic/photoelastic modulators.

Proceedings ArticleDOI
01 Aug 2021
TL;DR: The conventional method for load stepping in digital photoelasticity is updated by introducing a polarizer array camera into a circular polariscope, and the stress field can be evaluated by using a single optical configuration into the load stepping method.
Abstract: Digital photoelasticity allows to evaluate the stress field in loaded bodies. There, load stepping method by Ekman and Nurse allowed to avoid inconsistencies and ambiguities. However, it did not become popular by needing six images from two polariscope configurations a three load steeps. This paper updates the conventional method by introducing a polarizer array camera into a circular polariscope. Hence, polarizations of 0° and 90° from a Baumer VCXU50MP camera conduced to bright, and dark field images, simultaneously.With this work, the stress field can be evaluated by using a single optical configuration into the load stepping method.

Journal ArticleDOI
TL;DR: In this paper, an optical apparatus based on the dynamic photoelasticity technique was developed to visualize and analyze the propagation of the Krauklis wave within an analog fluid-filled fracture.
Abstract: We have developed an optical apparatus based on the dynamic photoelasticity technique to visualize and analyze the propagation of the Krauklis wave within an analog fluid-filled fracture. A...

Journal ArticleDOI
TL;DR: In this article, the authors derived the Kolossoff-Muskhelishvili stress function of an infinite plate with a central closed inclined crack with a single KI singular term at the crack tip and found that the distribution of each stress component around the crack is affected by the friction coefficient of the crack surface and the dip angle of crack.

Journal ArticleDOI
10 Sep 2021
TL;DR: In this paper, the authors studied the elasto-optic behavior of stressed cubic crystals and isotropic materials (e.g., glasses) and obtained the explicit dependence of the refraction indices on the stress (either applied or residual).
Abstract: We study the elasto-optic behavior of stressed cubic crystals (all classes) and isotropic materials (like e.g., glasses). We obtain the explicit dependence of the refraction indices on the stress (either applied or residual), as well as a mild generalization of the Brewster law for cubic crystals. We show also that the optic indicatrix and the stress ellipsoid are coaxial only in the isotropic case. This theory allows the improvement of the measurement techniques, as photoelasticity, on cubic crystals and optically isotropic materials.

Proceedings ArticleDOI
01 Aug 2021
TL;DR: In this article, the authors evaluate residual and thermal stresses using temporal analysis of color in photoelasticity images and apply k-means analysis to three discs with residual stresses in different zones.
Abstract: Evaluation of residual and thermal stresses using temporal analysis of color in photoelasticity images was applied to three discs with residual stresses in different zones. The stress field generated by a compressive load is deformed under residual stress presence. 3D color trajectories for interest pixels show behavior differences between locations with and without residual stress. Finally, k-means analysis for three experiments shows the presence of residual stresses and relates their temporal behavior with a high stress level zone.

Proceedings ArticleDOI
01 Aug 2021
TL;DR: In this article, the effect of fractal concentrators is evaluated by means of digital photoelasticity by considering a circular disc of epoxy resin, a Canon color camera and a Baumer VCXU-50MP polarized camera.
Abstract: Identifying the state of stress around a concentrator is essential in a loaded structure. However, most studies are based on circular geometries, leaving aside complex ones such as fractals. In this paper, the effect of fractal concentrators are evaluated by means of digital photoelasticity by considering a circular disc of epoxy resin, a Canon color camera and a Baumer VCXU-50MP polarized camera. Additionally, a phase map was obtained with phase shifting, and phase wavelengths stepping algorithms. The digital photoelasticity executed detection of stress fields related to the fractal concentrator.