Experimental Mechanics最新文献

{"title":"Digital Image Correlation at Extreme Temperatures Using Shortwave Ultraviolet (UV-C) Lights and Filters","authors":"P. Dewanjee,&nbsp;M. A. Lea,&nbsp;L. J. Rowley,&nbsp;M. W. Estrada,&nbsp;R. K. Singh,&nbsp;S. Sarker,&nbsp;R. B. Berke","doi":"10.1007/s11340-024-01044-2","DOIUrl":"10.1007/s11340-024-01044-2","url":null,"abstract":"<div><h3>Background</h3><p>DIC is a widely used optical method that uses cameras to track the motion of an applied random surface pattern to measure the full-field deformation. Due to its non-contacting nature, DIC is very preferable to be used in the areas of high temperature experimental mechanics. One of the biggest challenges of DIC at extreme temperatures is the blackbody radiation emitted from the glowing surface of the specimen. This glow from the blackbody radiation of the specimen is relatively higher at longer wavelengths and lower at shorter wavelengths.    </p><h3>Objective</h3><p>Previously, studies have shown the usefulness of using shorter wavelength of lights such as blue filtered light (450 nm) and UV-A filtered light (365 nm) for high temperature measurements. By contrast, this study uses UV-C filtered technique which utilizes even shorter wavelength of filtered light (UV-C, 254 nm) to demonstrate its effectiveness at elevated temperatures.</p><h3>Methods</h3><p>Four different DIC techniques using an unfiltered blue light (200–1000 nm), a blue filtered light (450 nm), a UV-A filtered light (365 nm), and a UV-C (254 nm) filtered light have been performed at extreme temperatures in this study. </p><h3>Results</h3><p>It was found that the techniques using unfiltered blue, blue filtered, and UV-A filtered lights could only go up to a temperature of 900 °C, 1200 °C, and 1600 °C respectively before showing significant saturations in the images.</p><h3>Conclusions</h3><p>The new UV-C DIC showed no sign of saturation even up to a temperature of 1600 °C while providing comparable axial displacement and coefficient of thermal expansion (CTE) data and therefore demonstrating the usefulness of this method in higher temperatures. We also include helpful recommendations for how to produce speckle patterns having sufficient contrast at UV-C wavelengths.</p></div>","PeriodicalId":552,"journal":{"name":"Experimental Mechanics","volume":"64 4","pages":"551 - 563"},"PeriodicalIF":2.0,"publicationDate":"2024-03-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140076564","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":"Biaxial Extension of Cruciform Specimens: Embedding Equilibrium Into Design and Constitutive Characterization","authors":"G. Vitucci","doi":"10.1007/s11340-024-01052-2","DOIUrl":"10.1007/s11340-024-01052-2","url":null,"abstract":"<div><h3>Background</h3><p>Main desired features of biaxial tests are: uniformity of stresses and strains; high strain levels in gauge areas; reliable constitutive parameters identification. Despite cruciform specimen suitability to modern tensile devices, standard testing techniques are still debated because of difficulties in matching these demands.</p><h3>Objective</h3><p>This work aims at providing rational performance objectives and efficient cruciform specimens shapes in view of constitutive characterization.</p><h3>Methods</h3><p>Objective performance is evaluated along particular lines lying on principal directions in equibiaxial tensile tests. A rich specimen profile geometry is purposely optimized via finite elements analysis by varying cost function and material compressibility. Experimental tests, monitored via digital image correlation, are carried out for validation.</p><h3>Results</h3><p>New shapes are designed and tested in a biaxial tensile apparatus and show to perform better than existing ones. Elastic parameter identification is efficiently performed by only exploiting full field strain measurements along statically significant lines.</p><h3>Conclusions</h3><p>Small gauge areas and small fillet radii cruciform specimens approach the ideal deformation behaviour. For the constitutive parameters identification in planar tensile experiments, it suffices to monitor strains along the gauge lines.</p></div>","PeriodicalId":552,"journal":{"name":"Experimental Mechanics","volume":"64 4","pages":"539 - 550"},"PeriodicalIF":2.0,"publicationDate":"2024-03-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s11340-024-01052-2.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140073559","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":"On the Cover: Unique Identification of Stiffness Parameters in Hyperelastic Models for Anisotropic, Deformable, Thin Materials Based on a Single Experiment - A Feasibility Study Based on Virtual Full-Field Data","authors":"","doi":"10.1007/s11340-024-01051-3","DOIUrl":"10.1007/s11340-024-01051-3","url":null,"abstract":"","PeriodicalId":552,"journal":{"name":"Experimental Mechanics","volume":"64 3","pages":"293 - 293"},"PeriodicalIF":2.0,"publicationDate":"2024-03-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140886136","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 Improved Strain Field Reconstruction Method Based on Digital Twin for Test Monitoring","authors":"B. Wang,&nbsp;X. Ke,&nbsp;Z. Song,&nbsp;K. Du,&nbsp;X. Bi,&nbsp;P. Hao,&nbsp;C. Zhou","doi":"10.1007/s11340-024-01035-3","DOIUrl":"10.1007/s11340-024-01035-3","url":null,"abstract":"<div><h3>Background</h3><p>For the static loading test in the aerospace field, conventional strain field reconstruction methods relying on finite element analysis (FEA) or test data are difficult to meet the accuracy requirements of test monitoring.</p><h3>Objective</h3><p>This study aims to construct a high-accuracy strain field for real-time test monitoring.</p><h3>Methods</h3><p>An improved strain field reconstruction method based on digital twin (DT) named as DT-SFRM is proposed. The DT is built by data fusion of FEA results and test data, which combines the benefits of these data. The FEA conducted before formal test provides approximate strain field distribution, and the strain gauges data with high accuracy are used to modify FEA strain fields in real time. After that, the real-time DT is used to determine the possible risk regions of test articles. Finally, a large opening cylindrical shell (LOCS) buckling test is conducted to validate the advantages of DT-SFRM.</p><h3>Results</h3><p>Results show that the accuracy of DT-SFRM is much higher and less affected by the nonlinearity of test data than that of conventional methods. Compared with the time cost by conventional real-time FEA (about 50 min), the DT method only takes 9s to reconstruct strain field, and the possible risk regions predicted by DT-SFRM are more consistent with test buckling regions of LOCS than conventional methods.</p><h3>Conclusions</h3><p>The DT-SFRM is validated to have a higher accuracy and better monitoring effect, and it is more suitable for test monitoring of complex structures.</p></div>","PeriodicalId":552,"journal":{"name":"Experimental Mechanics","volume":"64 4","pages":"519 - 537"},"PeriodicalIF":2.0,"publicationDate":"2024-03-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140056415","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":"Near Edge Residual Stress Measurement Using Incremental Hole Drilling","authors":"M. D. Olson,&nbsp;A. T. DeWald,&nbsp;B. T. Watanabe","doi":"10.1007/s11340-024-01041-5","DOIUrl":"10.1007/s11340-024-01041-5","url":null,"abstract":"<div><h3>Background</h3><p>Hole drilling is a measurement technique used to determine near surface residual stresses and has been codified in ASTM E837-20. In ASTM E837-20, the minimum allowable distance to a free edge is prescribed as 1.5 times the gauge circle diameter.</p><h3>Objective</h3><p>This work examines the effect arising from the distance from a free edge on a hole drilling measurement and provides an approach to determine residual stress for measurements where the edge distance is closer than that currently permitted by ASTM E837-20.</p><h3>Methods</h3><p>Numerical experiments were performed to understand how the compliance matrices change when the distance from a hole drilling measurement to a free edge varies. In addition, a series of hole drilling measurements were performed at various distances from a free edge using a shot peened aluminum plate with a nominally equibiaxial stress state to demonstrate the approach.</p><h3>Results</h3><p>The numerical experiments determined that the use of corrected compliance matrices is appropriate when the edge distance is as small as 0.35 times the gauge circle diameter. Physical measurements supported the use of custom compliance matrices for a given free edge distance and specimen thicknesses.</p></div>","PeriodicalId":552,"journal":{"name":"Experimental Mechanics","volume":"64 4","pages":"501 - 517"},"PeriodicalIF":2.0,"publicationDate":"2024-03-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140045159","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":"Stress Evaluation Through the Layers of a Fibre-Metal Hybrid Composite by IHD: An Experimental Study","authors":"J. P. Nobre,&nbsp;T. C. Smit,&nbsp;R. Reid,&nbsp;Q. Qhola,&nbsp;T. Wu,&nbsp;T. Niendorf","doi":"10.1007/s11340-024-01047-z","DOIUrl":"10.1007/s11340-024-01047-z","url":null,"abstract":"<div><h3>Background</h3><p>Incremental hole-drilling (IHD) has shown its importance in the measurement of the residual stress distribution within the layers of composite laminates. However, validation of these results is still an open issue, especially near the interfaces between plies. </p><h3>Objectives</h3><p>In this context, this study is focused on experimentally verifying its applicability to fibre metal laminates.</p><h3>Methods</h3><p>Tensile loads are applied to cross-ply GFRP-steel [0/90/steel]s samples. Due to the difference in the mechanical properties of each ply, Classical Lamination Theory (CLT) predicts a distribution of the uniform stress within each layer, with pulse gradients between them. The interfaces act as discontinuous regions between the plies. The experimental determination of such stress variation is challenging and is the focus of this research. A horizontal tensile test device was designed and built for this purpose. A differential method is used to eliminate the effect of the existing residual stresses in the samples, providing a procedure to evaluate the ability of the IHD technique to determine the distribution of stress due to the applied tensile loads only. The experimentally measured strain-depth relaxation curves are compared with those determined numerically using the finite element method (FEM) to simulate the hole-drilling. Both are used as input for the IHD stress calculation method (unit pulse integral method). The distribution of stress through the composite laminate, determined by classical lamination theory (CLT), is used as a reference.</p><h3>Results</h3><p>Unit pulse integral method results, using the experimental and numerical strain-depth relaxation curves, compare reasonably well with those predicted by CLT, provided that there is no material damage due to high applied loads.</p><h3>Conclusions</h3><p>IHD seems to be an important measurement technique to determine the distribution of residual stresses in fibre metal laminates and should be further developed for a better assessment of the residual stresses at the interfaces between plies.</p></div>","PeriodicalId":552,"journal":{"name":"Experimental Mechanics","volume":"64 4","pages":"487 - 500"},"PeriodicalIF":2.0,"publicationDate":"2024-03-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s11340-024-01047-z.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140044632","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":"Ballistic and Blast-Relevant, High-Rate Material Properties of Physically and Chemically Crosslinked Hydrogels","authors":"E. C. Bremer-Sai,&nbsp;J. Yang,&nbsp;A. McGhee,&nbsp;C. Franck","doi":"10.1007/s11340-024-01043-3","DOIUrl":"10.1007/s11340-024-01043-3","url":null,"abstract":"<div><h3>Background</h3><p>Hydrogels are one of the most ubiquitous polymeric materials. Among them gelatin, agarose and polyacrylamide-based formulations have been effectively utilized in a variety of biomedical and defense-related applications including ultrasound-based therapies and soft tissue injury investigations stemming from ballistic and blast exposures. Interestingly, while in most cases accurate prediction of the mechanical response of these surrogate gels requires knowledge of the underlying finite deformation, high-strain rate material properties, it is these properties that have remained scarce in the literature.</p><h3>Objective</h3><p>Building on our prior works using Inertial Microcavitation Rheometry (IMR), here we present a comprehensive list of the high-strain rate (&gt; 10<span>(^3)</span> 1/s) mechanical properties of these three popular classes of hydrogel materials characterized via laser-based IMR, further showing that the choice in finite-deformation, rate-dependent constitutive model can be informed directly by the type of crosslinking mechanism and resultant network structure of the hydrogel, thus providing a chemophysical basis of the the choice of phenomenological constitutive model.</p><h3>Methods</h3><p>We analyze existing experimental gelatin IMR datasets and compare the results with prior data on polyacrylamide.</p><h3>Results</h3><p>We show that a Neo-Hookean Kelvin-Voigt (NHKV) model can suitably simulate the high-rate material response of dynamic, physically crosslinked hydrogels like gelatin, while the introduction of a strain-stiffening parameter through the use of the quadratic Kelvin-Voigt (qKV) model was necessary to appropriately model chemically crosslinked hydrogels such as polyacrylamide due to the nature of the static,covalent bonds that comprise their structure.</p><h3>Conclusions</h3><p>In this brief we show that knowledge of the type of underlying polymer structure, including its bond mobility, can directly inform the appropriate finite deformation, time-dependent viscoelastic material model for commonly employed tissue surrogate hydrogels undergoing high strain rate loading within the ballistic and blast regimes.</p></div>","PeriodicalId":552,"journal":{"name":"Experimental Mechanics","volume":"64 4","pages":"587 - 592"},"PeriodicalIF":2.0,"publicationDate":"2024-03-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s11340-024-01043-3.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140036214","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":"Improvement in Calibration Procedure in Nanoindentation: An Indenter Bluntness Indicator","authors":"D. Chicot,&nbsp;A. Montagne,&nbsp;A. Mejias,&nbsp;F. Roudet,&nbsp;T. Coorevits","doi":"10.1007/s11340-024-01048-y","DOIUrl":"10.1007/s11340-024-01048-y","url":null,"abstract":"<div><h3>Background</h3><p>Nanoindentation experiments require the calibration of the tip area function, which involves up to 9 fitting coefficients following classical method. These coefficients are determined from indentation tests on a reference material. However, their values may vary from one test batch to another. Consequently, these coefficients cannot describe the amplitude of the indenter tip defect.</p><h3>Objective</h3><p>The main objective of this study is to propose a contact area function that uses only one fitting coefficient to represent the indenter tip defect. This coefficient corresponds to the distance between the blunt and ideal indenter tip.</p><h3>Methodology</h3><p>To demonstrate the efficiency of the proposed contact area function, we reanalyzed nearly 40 calibration procedures, while keeping the same experimental protocol, performed between 2014 and today. A novel two-step calibration methodology is advanced. We compared the results of the proposed method to those obtained with the classic methodology.</p><h3>Results</h3><p>This two-step methodology was applied to a fused silica calibration sample. The values of the Young's modulus and instrumented hardness are equals to 71 and 10 GPa, respectively. The length of the indenter tip defect increases gradually from 5 to 30 nm accordingly to the frequency of use of the indenter. The values of the mechanical properties calculated by this methodology are in good agreement with those obtained using the classical contact area function.</p><h3>Conclusion</h3><p>The methodology presented in this paper demonstrates its ability to accurately calibrate the tip area function. This new calibration procedure considers both the Young’s modulus and the tip defect parameter as free parameters. Furthermore, the calibration parameters have a clear physical meaning and their values remain stables from one batch to another.</p></div>","PeriodicalId":552,"journal":{"name":"Experimental Mechanics","volume":"64 4","pages":"467 - 485"},"PeriodicalIF":2.0,"publicationDate":"2024-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140018544","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":"Development and Analysis of an On-Road Torque Measurement Device for Trucks","authors":"J. Hyttinen,&nbsp;H. Wentzel,&nbsp;R. Österlöf,&nbsp;J. Jerrelind,&nbsp;L. Drugge","doi":"10.1007/s11340-024-01030-8","DOIUrl":"10.1007/s11340-024-01030-8","url":null,"abstract":"<div><h3>Background</h3><p>Rolling resistance and aerodynamic losses cause a significant part of a truck’s energy consumption. Therefore there is an interest from both vehicle manufacturers and regulators to measure these losses to understand, quantify and reduce the energy consumption of vehicles. On-road measurements are particularly interesting because it enables testing in various ambient conditions and road surfaces with vehicles in service.</p><h3>Objective</h3><p>Common driving loss measurement devices require unique instrumented measurement wheels, which hinders effective measurements of multiple tyre sets or measurements of vehicles in service. For this purpose, the objective is to develop a novel load-sensing device for measuring braking or driving torque.</p><h3>Methods</h3><p>The strength of the measurement device is calculated using finite element methods, and the output signal is simulated using virtual strain gauge simulations. In addition to the signal simulation, the device is calibrated using a torsional test rig.</p><h3>Results</h3><p>The simulation results confirm that the device fulfils the strength requirements and is able to resolve low torque levels. The output signal is simulated for the novel cascaded multi-Wheatstone bridge using the strains extracted from the finite element analysis. The simulations and measurements show that the measurement signal is linear and not sensitive to other load directions. The device is tested on a truck, and the effort of mounting the device is comparable to a regular tyre change.</p><h3>Conclusions</h3><p>A novel driving loss measurement device design is presented with an innovative positioning of strain gauges decoupling the parasitic loads from the driving loss measurements. The design allows on-road testing using conventional wheels without requiring special measurement wheels or instrumentation of drive shafts, enabling more affordable and accurate measurements.</p></div>","PeriodicalId":552,"journal":{"name":"Experimental Mechanics","volume":"64 4","pages":"455 - 466"},"PeriodicalIF":2.0,"publicationDate":"2024-02-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s11340-024-01030-8.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140007987","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":"Non-Associated Flow Rule Constitutive Modeling Considering Anisotropic Hardening for the Forming Analysis of Orthotropic Sheet Metal","authors":"Y. Zhang,&nbsp;Y. Duan,&nbsp;Z. Mu,&nbsp;P. Fu,&nbsp;J. Zhao","doi":"10.1007/s11340-024-01032-6","DOIUrl":"10.1007/s11340-024-01032-6","url":null,"abstract":"<div><h3>Background</h3><p>The evolution of anisotropy has an important influence on the forming of parts under large deformation. However, most of the current yield criteria do not consider the evolution.</p><h3>Objective</h3><p>An anisotropic constitutive model based on non-associated flow rule (non-AFR) was established for orthotropic sheet metal. The classical quadratic Hill48 model was used to describe the yield anisotropy and plastic deformation anisotropy, respectively.</p><h3>Methods</h3><p>According to the principle of equivalent plastic work, the existence and significance of anisotropy evolution with plastic deformation were revealed. In order to improve the prediction accuracy of the model, a continuous capture scheme considering anisotropic hardening was proposed.</p><h3>Results</h3><p>The evolution of directional yield stress, directional r-value and yield locus was well captured by the developed model. To further verify the model, square box deep drawing tests of different strokes of the punch were carried out. Compared with the experimental results, the developed model could predict the material flow behavior in flange area and thickness thinning behavior, which actually reflected the evolution behavior of directional flow stress and directional r-value of sheet metal respectively.</p><h3>Conclusion</h3><p>The developed model improves the prediction accuracy of anisotropic sheet metal forming, and can provide an effective reference scheme for large deformation problems in industrial production.</p></div>","PeriodicalId":552,"journal":{"name":"Experimental Mechanics","volume":"64 3","pages":"305 - 323"},"PeriodicalIF":2.0,"publicationDate":"2024-02-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139951007","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}