Experimental Mechanics最新文献

{"title":"Spherical Indentation Method for Measuring Biaxial Residual Stresses Without Using Stress-Free Sample","authors":"G. Peng,&nbsp;L. Zhang,&nbsp;S. Li,&nbsp;Y. Huan,&nbsp;Z. Piao,&nbsp;P. Chen","doi":"10.1007/s11340-024-01119-0","DOIUrl":"10.1007/s11340-024-01119-0","url":null,"abstract":"<div><h3>Background</h3><p>Since residual stresses can affect the mechanical performance of in-service engineering structures, accurate evaluation of biaxial residual stresses is of great significance to service safety. Previous indentation methods for evaluating biaxial residual stresses usually require a stress<b>-</b>free sample as a reference, which is difficult to obtain in engineering.</p><h3>Objective</h3><p>In present work, a spherical indentation method for evaluating biaxial residual stresses without using stress<b>-</b>free sample was established.</p><h3>Methods</h3><p>To avoid using stress<b>-</b>free sample, a method for deriving the loading work in unstressed state from the load<b>-</b>depth curve in stressed state, was established. Through dimensional analysis and finite simulations, biaxial residual stresses were quantitatively correlated to the fractional change in loading work between stressed and unstressed states, and the flattening factor of residual imprint. Based on such correlations, biaxial residual stresses can be evaluated without using stress<b>-</b>free sample. A biaxial stress-generating jig was used to validate the method experimentally.</p><h3>Results</h3><p>Finite element analyses and experimental results demonstrate that the proposed method could evaluate biaxial residual stresses with reasonable accuracy.</p><h3>Conclusions</h3><p>Combined with portable micro-indentation device, the proposed method has broad application prospects in evaluating biaxial residual stress of in-service engineering structures.</p></div>","PeriodicalId":552,"journal":{"name":"Experimental Mechanics","volume":"65 1","pages":"89 - 106"},"PeriodicalIF":2.0,"publicationDate":"2024-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142995795","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effect of Solution Methods for Evolutionary R-Values on the Prediction of Anisotropic Yield Behavior","authors":"Z. Mu,&nbsp;J. Liu,&nbsp;T. Hou,&nbsp;X. Dai,&nbsp;W. Wang,&nbsp;S. Ma","doi":"10.1007/s11340-024-01122-5","DOIUrl":"10.1007/s11340-024-01122-5","url":null,"abstract":"<div><h3>Background</h3><p>The anisotropic behavior of sheet metal has a significant influence on the plastic forming process, especially the accurate description of the plastic flow (<i>r</i>-value).</p><h3>Objective</h3><p>The purpose of this paper is to reveal the influence of different evolutionary <i>r</i>-value solution methods on yield model prediction.</p><h3>Methods</h3><p>Uniaxial and biaxial tensile experiments were carried out for DP590. The principles and results of <i>r</i>-value calculation based on slope method and polynomial fitting method are compared and analyzed. On this basis, the inverse solution method based on exponential function is established. The prediction results of Hill48, Hill48-non and Yld2000-2D yield models based on different <i>r</i>-value solution methods were compared. Furthermore, anisotropic yield models calibrated by different <i>r</i>-value solution methods are used as user material subroutine (VUMAT) to achieve cup-drawing simulation in ABAQUS.</p><h3>Results</h3><p>In the theoretical prediction of anisotropic yield model, the prediction accuracy of the three yield models is the best when the new inverse exponential function method is used. The earing height obtained by the three yield models based on inverse exponential function method calibration is more consistent with the physical experiment, while the prediction accuracy of the traditional slope method is the worst.</p><h3>Conclusions</h3><p>The appropriate <i>r</i>-value solution method can improve the predictive accuracy of anisotropic yield model. The research results provide a method for the anisotropic parameter calibration strategy of yield model considering anisotropic evolution, and provide an effective reference scheme for improving the prediction accuracy of deformation behavior in sheet metal stamping.</p><h3>Graphical Abstract</h3>\u0000<div><figure><div><div><picture><source><img></source></picture></div></div></figure></div></div>","PeriodicalId":552,"journal":{"name":"Experimental Mechanics","volume":"65 1","pages":"69 - 88"},"PeriodicalIF":2.0,"publicationDate":"2024-10-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142995799","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Shape Measurements of Lattice Materials from Few X-Ray Radiographs Using the 3D Virtual Image Correlation (3D-VIC) Method","authors":"L. Calmettes,&nbsp;M. L. M. François,&nbsp;J. Réthoré","doi":"10.1007/s11340-024-01116-3","DOIUrl":"10.1007/s11340-024-01116-3","url":null,"abstract":"<div><h3>Background</h3><p>the development of additive manufacturing technologies (3D printing) has made it possible to manufacture complex structures such as architected materials. However, traditional inspection methods are not suited to these materials, which require volume inspection to examine their internal structure.</p><h3>Objective</h3><p>the aim is to provide a 3D shape measurement method based on the initial computer-aided design (CAD) model used for 3D printing and X-ray radiographs.</p><h3>Method</h3><p>the CAD model is deformed until its virtual radiographs obtained by simulating the absorption of X-rays through the solid register with experimental radiographs. This registration is achieved by minimising a cost function with respect to the position of control points using radial basis function interpolation.</p><h3>Results</h3><p>the method’s performance is first evaluated using synthetic data. Its robustness is assessed with respect to image resolution, number of radiographs and noise level. Subsequently, the geometry of a solid with a tetrahedral architecture was quantified by means of a mere five radiographs. Global variation in shape and local defects in lattice structure can be detected.</p><h3>Conclusions</h3><p>the method enables the in-volume shape of architected materials to be checked without reconstructing the 3D computed tomography volume, but from just a few radiographs. It is robust and can detect local defects.</p></div>","PeriodicalId":552,"journal":{"name":"Experimental Mechanics","volume":"65 1","pages":"55 - 68"},"PeriodicalIF":2.0,"publicationDate":"2024-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142995412","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"MorphFlow: Estimating Motion in In-Situ Tests of Concrete","authors":"T. Nogatz,&nbsp;C. Redenbach,&nbsp;K. Schladitz","doi":"10.1007/s11340-024-01104-7","DOIUrl":"10.1007/s11340-024-01104-7","url":null,"abstract":"<div><h3>Background</h3><p><i>In situ</i> Computed Tomography is a valuable tool to investigate failure mechanics of materials in 3D. For brittle materials with sudden fracture like concrete however, state-of-the-art methods such as Digital Volume Correlation fail to produce displacement fields that display the discontinuous behavior of load induced cracking correctly.</p><h3>Objective</h3><p>The main objective is to develop an algorithm that calculates displacement fields for large-scale <i>in situ</i> experiments on concrete.</p><h3>Methods</h3><p>The algorithm presented is based on a 3D Optical Flow method solved by a primal-dual procedure and equipped with a coarse-to-fine scheme based on morphological wavelets. The algorithm is publicly available. Our evaluation focuses on the beneficial use of morphological wavelets over classical ones, and on the ability to produce reliable results with limited data. Applying the primal-dual scheme to <i>in situ</i> tests and using morphological wavelets are novel contributions.</p><h3>Results</h3><p>The results show that our algorithm cannot only cope with large volume images, but also produces discontinuous displacement fields that yield high strain in fractured regions. It does not only perform better than state-of-the-art methods, but also achieves sufficient results on reduced data. The morphological wavelets play a key role in this finding - they even allow to deduce cracks of widths less than a voxel.</p><h3>Conclusion</h3><p>Displacement calculation for <i>in situ</i> tests of brittle materials requires voxel-accurate displacement fields that allow for discontinuities. The presented algorithm fulfills these requirements and therefore is a powerful tool for future understanding of failure mechanics in concrete.</p></div>","PeriodicalId":552,"journal":{"name":"Experimental Mechanics","volume":"65 1","pages":"35 - 53"},"PeriodicalIF":2.0,"publicationDate":"2024-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s11340-024-01104-7.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142994787","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A Note of Gratitude from the Editor-in-Chief","authors":"A. Zehnder","doi":"10.1007/s11340-024-01121-6","DOIUrl":"10.1007/s11340-024-01121-6","url":null,"abstract":"","PeriodicalId":552,"journal":{"name":"Experimental Mechanics","volume":"64 9","pages":"1383 - 1383"},"PeriodicalIF":2.0,"publicationDate":"2024-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142443228","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"On the Cover: Accounting for Localized Deformation: A Simple Computation of True Stress in Micropillar Compression Experiments","authors":"","doi":"10.1007/s11340-024-01120-7","DOIUrl":"10.1007/s11340-024-01120-7","url":null,"abstract":"","PeriodicalId":552,"journal":{"name":"Experimental Mechanics","volume":"64 9","pages":"1381 - 1381"},"PeriodicalIF":2.0,"publicationDate":"2024-10-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142443227","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A Novel Method to In-Situ Characterize Fatigue Crack Growth Behavior of Nickel-Based Superalloys By Laser Thermography","authors":"C. Geng,&nbsp;Q. Zhong,&nbsp;H. Luo,&nbsp;W. Shi,&nbsp;H. Xie,&nbsp;W. He","doi":"10.1007/s11340-024-01113-6","DOIUrl":"10.1007/s11340-024-01113-6","url":null,"abstract":"<div><h3>Background</h3><p>Nickel-based superalloys are key materials for aero-engine hot-end components, and fatigue is one of their most typical failure forms. In the field of fatigue research, in-situ characterization of crack growth behavior is crucial, and more intuitive and accurate characterization methods need to be developed.</p><h3>Objective</h3><p>In this work, to better understand their fatigue crack growth behavior, we have developed new methods for in-situ characterization of crack growth behavior using laser thermography detection technique.</p><h3>Methods</h3><p>According to the thermal images of sample surfaces captured during the fatigue process, a method for positioning crack tip based on Prewitt edge detection is proposed, and a novel parameter, i.e., the crack opening temperature gradient (COTG), is defined to evaluate the crack closure effect.</p><h3>Results</h3><p>Based on the variation characteristics of COTG with load rate, the crack initial opening load rate (CIOLR) and crack opening load ratio (COLR) can be determined under different fatigue cycles. The results show that CIOTG and COTG tend to decrease with increasing fatigue cycles.</p><h3>Conclusion</h3><p>This work provides a visual and quantitative in-situ method for crack detection and characterization of the crack closure effect in fatigue testing.</p></div>","PeriodicalId":552,"journal":{"name":"Experimental Mechanics","volume":"65 1","pages":"5 - 23"},"PeriodicalIF":2.0,"publicationDate":"2024-10-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142994563","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"An INNOVative Approach for Mechanical Characterization of Coatings on Fibres","authors":"M. Benzarti,&nbsp;P. Henry","doi":"10.1007/s11340-024-01117-2","DOIUrl":"10.1007/s11340-024-01117-2","url":null,"abstract":"<div><h3>Background</h3><p>Varnish is used in many domains to enhance wear resistance, mechanical behaviour or chemical resistance. To characterize varnish cohesion or adhesion on plane surface, a scratch-test is predominantly used. In order to investigate coating properties on fibres, the common method uses tensile tests.</p><h3>Objective</h3><p>The aim of this paper was to investigate the adhesion of varnish on a monofibre of polyamide using an out of the box procedure based on scratch tests. To do so, a specific device was conceived to enable a scratch test on a single fibre.</p><h3>Methods</h3><p>Adhesion between varnish and a monofibre of nylon was investigated using several series of scratch tests on fibres coated by two types of varnish. Coating toughness and adhesion were investigated according to the coating composition and thermal treatment. A comparison between the different prints was discussed to characterize the effect of varnish type on the scratch resistance and to determine the parameters that influence this adhesion using scratch-test.</p><h3>Results</h3><p>The obtained results highlighted the influence of the thermal treatment imposed to the fibres on the mechanical behaviour. Tensile tests were conducted on the three types of samples in order to establish a link in terms of classification between a well-known characterization experiment and the presented scratch test.</p><h3>Conclusion</h3><p>Beyond the investigation of varnish/nylon fibre adhesion, this paper mostly aims at validating an innovative process for the characterization of coatings deposited on curved surfaces like fibres.</p></div>","PeriodicalId":552,"journal":{"name":"Experimental Mechanics","volume":"65 1","pages":"25 - 34"},"PeriodicalIF":2.0,"publicationDate":"2024-10-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142994564","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Dynamic Magneto-Mechanical Analysis of Isotropic and Anisotropic Magneto-Active Elastomers","authors":"C.D. Pierce,&nbsp;N.J. Salim,&nbsp;K.H. Matlack","doi":"10.1007/s11340-024-01115-4","DOIUrl":"10.1007/s11340-024-01115-4","url":null,"abstract":"<div><h3>Background</h3><p>Magneto-active elastomers (MAEs) are soft composite materials comprising ferromagnetic particles in an elastomer matrix which exhibit a magnetically-induced effective modulus change. The change in modulus has been experimentally studied in many MAE formulations using several techniques; however, this makes comparisons between studies difficult, and there lacks a comprehensive study on the dynamic magneto-mechanical properties of MAEs.</p><h3>Objective</h3><p>In this article, we seek to understand the effect of mechanical loading direction and magnetic field orientation on the dynamic magneto-mechanical response of isotropic and anisotropic MAEs.</p><h3>Methods</h3><p>We develop a new apparatus to perform dynamic mechanical analysis of MAEs at frequencies up to 600Hz subject to magnetic fields of varying strength. We measure the magnetically-induced modulus change in MAEs prepared from a single elastomer-particle combination and specimen geometry, systematically varying the anisotropy direction relative to the magnetic field.</p><h3>Results</h3><p>Our results show that isotropic MAEs are up to three times stiffer and anisotropic MAEs up to 65 times stiffer than pure elastomer. Of all configurations studied, the longitudinal modulus of anisotropic MAEs exhibits the largest absolute magnetically-induced change while the transverse modulus exhibits the largest relative change. The magnetically-induced change in loss factor depends on anisotropy and loading condition: isotropic MAEs have no change in loss factor while anisotropic MAEs become less lossy at low strain amplitudes but more lossy at high strain amplitudes.</p><h3>Conclusions</h3><p>These results provide new insights into the fundamental mechanisms by which microstructure and magnetic field interact to affect the MAE effective properties.</p></div>","PeriodicalId":552,"journal":{"name":"Experimental Mechanics","volume":"64 9","pages":"1601 - 1618"},"PeriodicalIF":2.0,"publicationDate":"2024-09-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142443266","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Fatigue Damage Evolution in SS316L Produced by Powder Bed Fusion in Different Orientations with Reused Powder Feedstock","authors":"M. Kopec,&nbsp;U. Gunputh,&nbsp;G. Williams,&nbsp;W. Macek,&nbsp;Z.L. Kowalewski,&nbsp;P. Wood","doi":"10.1007/s11340-024-01118-1","DOIUrl":"10.1007/s11340-024-01118-1","url":null,"abstract":"<div><h3>Background</h3><p>Metal Laser Powder Bed Fusion Melting (LPBF-M) is considered economically viable and environmentally sustainable because of the possibility of reusing the residual powder feedstock leftover in the build chamber after a part build is completed. There is however limited information on the fatigue damage development of LPBF-M samples made from reused feedstock.</p><h3>Objective</h3><p>In this paper, the stainless steel 316 L (SS316L) powder feedstock was examined and characterised after 25 reuses, following which the fatigue damage development of material samples made from the reused powder was assessed.</p><h3>Methods</h3><p>The suitability of the powder to LPBF-M technology was evaluated by microstructural observations and measurements of Hall flow, apparent and tapped density as well as Carr’s Index and Hausner ratio. LPBF-M bar samples in three build orientations (Z – vertical, XY – horizontal, ZX – 45° from the build plate) were built for fatigue testing. They were then subjected to fatigue testing under load control using full tension and compression cyclic loading and stress asymmetry coefficient equal to -1 in the range of stress amplitude from ± 300 MPa to ± 500 MPa.</p><h3>Results</h3><p>Samples made from reused powder (25 times) in the LPBF-M process exhibited similar fatigue performance to fresh unused powder although a lower ductility for vertical samples was observed during tensile testing. Printing in horizontal (XY) and diagonal (ZX) directions, with reused powder, improved the service life of the SS316L alloy in comparison to the vertical (Z).</p><h3>Conclusions</h3><p>Over the 25 reuses of the powder feedstock there was no measurable difference in the flowability between the fresh (Hall Flow: 21.4 s/50 g) and reused powder (Hall Flow: 20.6 s/50 g). This confirms a uniform and stable powder feeding process during LPBF-M for both fresh and reused powder. The analysis of fatigue damage parameter, D, concluded cyclic plasticity and ratcheting to be the main mechanism of damage.</p></div>","PeriodicalId":552,"journal":{"name":"Experimental Mechanics","volume":"65 4","pages":"427 - 442"},"PeriodicalIF":2.0,"publicationDate":"2024-09-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s11340-024-01118-1.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143919306","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}