Strain最新文献

{"title":"Strain special issue: Quantitative visualization testing techniques applied to civil engineering structures and materials","authors":"P. Forquin, E. Toussaint","doi":"10.1111/str.12353","DOIUrl":"https://doi.org/10.1111/str.12353","url":null,"abstract":"This special issue entitled “Quantitative visualization testing techniques applied to civil engineering structures and materials” follows the organization of a series of thematic workshops entitled “Techniques d'Imagerie pour la Caracté risation des Matériaux et des Structures du Génie Civil” (image-based techniques for the characterization of materials and structures in civil engineering). The different editions took place in France in the cities of Clermont-Ferrand (March 20–21, 2014), Grenoble (March 10–11, 2016) and Champs-sur-Marne (April 4–5, 2019), bringing together about 50 PhD students, post-doc, early career or senior researchers who gave oral or poster presentations in the field of the experimental mechanics applied to civil engineering structures and materials. The present special issue illustrates how much the quantitative measurement experimental techniques in that research field have progressed and diversified within the last decade. Among the quantitative testing techniques used in the presented papers, one may want to highlight the various full-field or multipoint measurement methods: 2D and 3D Digital Image Correlation, Grid method, Particle Image Tracking, Particle Imagery Velocimetry, Digital Volume Correlation, Sampling moiré, Reflection photoelasticity, Optical fibre sensors, among others. These test methods are applied to heterogeneous materials: concrete, fibre-reinforced concrete, textile-reinforced concrete, granular materials, etc., from the microscopic or nanoscopic scale to the metre or decameter scale when applied to concrete bridges or masonry walls in this present special issue. Applications concern various environmental conditions such as high temperatures, different moisture contents, or loading conditions like high strain-rates testing. The underlying damage mechanisms are investigated by different methods like X-ray microtomography, synchrotron radiation or rapid neutron tomography. The wealth of experimental evidence brings better understanding of the mechanical behaviour of these civil engineering materials and structures and leads to substantial progress in the identification and the development of predictive modelling using Finite or Discrete Element, damage, cohesive zone or mixed-mode fracture models. We would like to acknowledge the contribution from many people which made this special issue possible. We wish to express our warm thanks to our reviewers for their time and efforts in reviewing papers and the authors for their work in submitting and revising their manuscript. Our gratitude also goes to Pr. Fabrice Pierron, former editor-in-chief of STRAIN Journal, for his guidance and support throughout the entire process. Wishing you a pleasant and inspiring reading,","PeriodicalId":51176,"journal":{"name":"Strain","volume":null,"pages":null},"PeriodicalIF":2.1,"publicationDate":"2020-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1111/str.12353","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43663415","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Quantification of evolving moisture profiles in concrete samples subjected to temperature gradient by means of rapid neutron tomography: Influence of boundary conditions, hygro‐thermal loading history and spalling mitigation additives","authors":"A. Tengattini, S. Dal Pont, H. Cheikh Sleiman, F. Kisuka, M. Briffaut","doi":"10.1111/str.12371","DOIUrl":"https://doi.org/10.1111/str.12371","url":null,"abstract":"Concrete has a tendency to spall, that is, to eject layers when subjected to high temperatures. This is an erratic phenomenon, and our understanding of the underlying physical process is still limited. A driving process is moisture transfer, whose experimental investigation has so far mostly been limited to macroscopic or point‐wise observations, limiting both our understanding and the validation of the proposed models. In this paper, a non‐contact technique, neutron imaging, is used to extract a the full‐field distribution of moisture in 3D and in real time, while the concrete is heated at high temperatures. This reveals a number of processes often underestimated or ignored in the traditional experimental approaches reported in the literature. Notably, the effect on the evolving moisture profiles of varying heating rates for multiple insulation techniques as well the strong influence of the addition of spalling‐mitigating additives is presented. The first ever example of neutron tomography of a spalled sample is also reported, and some preliminary analyses of the effect that moisture clog formation and heating rates have on it are revealed.","PeriodicalId":51176,"journal":{"name":"Strain","volume":null,"pages":null},"PeriodicalIF":2.1,"publicationDate":"2020-10-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1111/str.12371","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47984468","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Investigation of the 2D assumption in the image‐based inertial impact test","authors":"J. Van Blitterswyk, L. Fletcher, F. Pierron","doi":"10.1111/str.12369","DOIUrl":"https://doi.org/10.1111/str.12369","url":null,"abstract":"The image‐based inertial impact (IBII) test has shown promise for measuring properties of composites at strain rates where existing test methods become unreliable due to inertial effects (> 102 s−1). Typically, the IBII tests are performed with a single camera, and therefore, to use surface measurements for material property identification, it is necessary to assume that the test is two‐dimensional. In this work, synchronised ultra‐high‐speed cameras are used to quantify the relevance of this assumption when nonuniform, through‐the‐thickness loading is applied to interlaminar samples. Initial experiments revealed that an angular misalignment of approximately 1° between the impact faces of the waveguide and projectile created a bending wave that propagated along the sample behind the axial pulse. Even under these conditions, consistent measurements of stiffness were made by assuming a linear distribution of the behaviour through‐the‐thickness. When the misalignment was reduced to 0.2°, the effects on single‐sided measurements were significantly reduced. The two alignment cases were compared to show that three‐dimensional loading had a small effect on stiffness identification (approximately 5% bias) relative to failure stress (approximately 30% bias). This study highlights the importance of impact alignment for reliable characterisation of the interlaminar failure stress and was used to establish guidelines for diagnosing loading issues from single‐sided measurements.","PeriodicalId":51176,"journal":{"name":"Strain","volume":null,"pages":null},"PeriodicalIF":2.1,"publicationDate":"2020-10-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1111/str.12369","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46132795","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Issue Information","authors":"","doi":"10.1111/str.12323","DOIUrl":"https://doi.org/10.1111/str.12323","url":null,"abstract":"No abstract is available for this article.","PeriodicalId":51176,"journal":{"name":"Strain","volume":null,"pages":null},"PeriodicalIF":2.1,"publicationDate":"2020-09-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1111/str.12323","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49626427","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Towards Material Testing 2.0. A review of test design for identification of constitutive parameters from full‐field measurements","authors":"F. Pierron, M. Grédiac","doi":"10.1111/str.12370","DOIUrl":"https://doi.org/10.1111/str.12370","url":null,"abstract":"Full‐field optical measurements like digital image correlation or the grid method have brought a paradigm shift in the experimental mechanics community. While inverse identification techniques like finite element model updating or the virtual fields method have been the object of significant developments, current test methods, inherited from the age of strain gauges or linear variable displacement transducers, are generally not well adapted to the rich information provided by these new measurement tools. This paper provides a review of the research dealing with the design and optimization of heterogeneous mechanical tests for the identification of material parameters from full‐field measurements, christened here Material Testing 2.0 (MT2.0).","PeriodicalId":51176,"journal":{"name":"Strain","volume":null,"pages":null},"PeriodicalIF":2.1,"publicationDate":"2020-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1111/str.12370","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42148183","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Experimental study of dry stone masonry walls using digital reflection photoelasticity","authors":"Pankaj Kumar, M. Hariprasad, A. Menon, K. Ramesh","doi":"10.1111/str.12372","DOIUrl":"https://doi.org/10.1111/str.12372","url":null,"abstract":"Response of dry stack stone masonry walls under mechanical loading is complex and difficult to determine, mainly due to heterogeneous and discrete nature of the components of the stone wall. In this paper, reflection photoelasticity is used on scaled down models of stone masonry wall under uniaxial compression. Two walls are tested, and the methods to obtain near perfect dry stack masonry for reflection photoelastic studies are presented. Five‐step phase‐shifting methods are employed with TFP/RGB photoelasticity to quantitatively analyse the mechanical behaviour of the dry stack masonry walls. Isochromatics and isoclinic data are processed to obtain other whole field experimental stress data. Highly stressed zones are observed resulting in distinctive localised vertical failure in some of the stone units. In dry stack masonry construction, the failure mechanism is found to be dictated by the contact mechanics, which are governed by the non‐uniformity of block geometry even in very regular dry stack masonry.","PeriodicalId":51176,"journal":{"name":"Strain","volume":null,"pages":null},"PeriodicalIF":2.1,"publicationDate":"2020-09-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1111/str.12372","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41874387","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Advances in analysis of total uncertainties in a semi‐invasive residual stress measurement method","authors":"S. Hossain, G. Zheng, D. Goudar","doi":"10.1111/str.12368","DOIUrl":"https://doi.org/10.1111/str.12368","url":null,"abstract":"The ability to characterise residual stress distribution accurately and over different length scales, particularly deep into an engineering part, plays a significant role in assessing structural integrity. Two most commonly used techniques to measure residual stress fields deep into engineering components include neutron diffraction (ND) and deep‐hole drilling (DHD). As the measurements depend on several physical quantities, they are susceptible to error. The error or uncertainties may turn substantial and compromise the suitability of the results. Although noninvasive, the neutron diffraction technique is neither readily available nor portable and is limited to approximately 60‐mm‐thick specimen; errors associated with results become unacceptable at greater flight paths. Moreover, a mock‐up representing the engineering component is normally used in the ND technique. In contrast, the DHD technique is portable and measures residual stresses with high spatial resolution. An error propagation technique was applied to develop an error analysis procedure taking into consideration various stages of the DHD method and successfully applied to different DHD measurements. An essential feature comprising the effect of plasticity due to the creation of reference hole in the DHD procedure has not yet been taken into account in the error analysis procedure. This paper briefly describes how the uncertainties due to the creation of the initial reference hole can be determined. The effect of plasticity in the drilling procedure is quantified in this study. This error is combined with other sources of error and formulated to determine the total error. An incremental DHD technique was used to measure the complex triaxial residual stress field in an as‐welded circular disc, and the measured data were used to illustrate the total error using the error analysis method developed in the study.","PeriodicalId":51176,"journal":{"name":"Strain","volume":null,"pages":null},"PeriodicalIF":2.1,"publicationDate":"2020-08-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1111/str.12368","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43885476","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Issue Information","authors":"","doi":"10.1111/str.12322","DOIUrl":"https://doi.org/10.1111/str.12322","url":null,"abstract":"No abstract is available for this article.","PeriodicalId":51176,"journal":{"name":"Strain","volume":null,"pages":null},"PeriodicalIF":2.1,"publicationDate":"2020-07-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1111/str.12322","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49312636","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Validation of the photomechanical spalling test in the case of non‐linear dynamic response: Application to a granite rock","authors":"B. Lukić, D. Saletti, P. Forquin","doi":"10.1111/str.12363","DOIUrl":"https://doi.org/10.1111/str.12363","url":null,"abstract":"In this paper, the use of the virtual fields method for the identification of a strongly asymmetric compression–tension response of rock‐like materials under dynamic tensile loading is investigated. The photomechanical spalling set‐up is used, which induces an indirect tensile load in a non‐balanced sample, and the inertial component of the test is directly related to the measured dynamic stress with no previous assumption on the material behaviour. This experimental method provides a direct route to identifying the material asymmetric constitutive response in compression and tension under a uniaxial stress state as well as the material non‐linear response after tensile strength is reached. To validate this approach, the entire measurement chain for the case of a post‐peak response is investigated through simulated experiments that incorporate a damage model and synthetic grid images. Finally, the method is applied to the case of granite rock, namely, a Bohus granite, as to directly measure the material asymmetric compression–tension and the softening response after peak tensile stress.","PeriodicalId":51176,"journal":{"name":"Strain","volume":null,"pages":null},"PeriodicalIF":2.1,"publicationDate":"2020-07-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1111/str.12363","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43412564","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"On the identification of cohesive zone model for curved crack in mortar","authors":"R. Vargas, A. Tsitova, F. Bernachy-Barbe, Benoit Bary, R. B. Canto, François Hild","doi":"10.1111/str.12364","DOIUrl":"https://doi.org/10.1111/str.12364","url":null,"abstract":"This paper proposes an approach to defining the path of a curved crack in a single‐edge notched specimen with gray level residuals extracted from digital image correlation, followed by the calibration of the parameters of a cohesive zone model. Only the experimental force is used in the cost function minimized via finite element model updating. The displacement and gray level residual fields allow for the validation of the calibrated parameters. Last, the results are confronted with those given by a straight crack to highlight the benefits of accounting for the actual crack path.","PeriodicalId":51176,"journal":{"name":"Strain","volume":null,"pages":null},"PeriodicalIF":2.1,"publicationDate":"2020-07-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1111/str.12364","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48757803","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}