Experimental Techniques最新文献

{"title":"Assessing Spatiotemporal Behavior of Human Gait: A Comparative Study Between Low-Cost Smartphone-Based Mocap and OptiTrack Systems","authors":"B. Castillo,&nbsp;C. Riascos,&nbsp;J. M. Franco,&nbsp;J. Marulanda,&nbsp;P. Thomson","doi":"10.1007/s40799-024-00716-x","DOIUrl":"10.1007/s40799-024-00716-x","url":null,"abstract":"<div><p>This study assessed the accuracy of a low-cost marker-based motion capture system with smartphone devices to estimate the spatiotemporal behavior of human gait in comparison with the performance of the commercial OptiTrack system. Initially, three test subjects were selected for the study, and after equipping them with passive retroreflective markers, they were recorded for gait velocities of 1.50, 1.90, and 2.30 <span>(mbullet {s}^{-1})</span> while collecting kinematic data and videos. The results showed that the smartphone motion capture system exhibited significant spatiotemporal tracking and accuracy in the x-y trajectories and estimation of joint relative angles of the hip, knee, and ankle joints (θ₁, θ₂, and θ₃, respectively) compared to the commercial OptiTrack system. In this comparison, an average goodness-of-FIT and normalized root mean square error of over 88.93% and 2.71% were obtained, respectively, for the joint relative angles of the hip and knee (θ₁ and θ2) in all tests performed. However, the accuracy of the joint relative angle of the ankle (θ3, average FIT: 71.04% and nRMSE: 4.26%) was lower because of the low capture rate of the retroreflective markers in the smartphone system and the higher relative velocity in the lower extremities of the test subjects, which generated noise in the calculation of x-y trajectories. This decrease in accuracy has been reported in other studies. However, both motion capture systems experienced marker data loss at the hip, highlighting the need for improvement in the spatial distribution of the optical devices. The OptiTrack system demonstrated better optical redundancy but still required improvements. In contrast, the smartphone system, with its inherent limitations in terms of optical redundancy and spatial distribution, can be enhanced by incorporating multiple cameras for a three-dimensional view. Despite these limitations, the low-cost smartphone system showed optimal performance with minimal errors compared with the commercial system, making it a cost-effective option with potential for further development. The rapid advancement of smartphone technology and its accessibility make it an attractive choice for motion capture applications.</p></div>","PeriodicalId":553,"journal":{"name":"Experimental Techniques","volume":"49 1","pages":"3 - 13"},"PeriodicalIF":1.5,"publicationDate":"2024-05-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s40799-024-00716-x.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140930564","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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":"Computational Fluid Dynamics-Based Analysis of Magnetic Field Effect on Improvement the Performance of Stepped Solar Still","authors":"K. Samadi,&nbsp;H. R. Goshayeshi,&nbsp;V. Nejati,&nbsp;S. R. Saleh,&nbsp;I. Chaer","doi":"10.1007/s40799-024-00714-z","DOIUrl":"10.1007/s40799-024-00714-z","url":null,"abstract":"<div><p>This study focuses on improving the performance of a solar-powered desalination unit by investigating the effect of a magnetic field applied by a solenoid using a numerical solution method. The calculations in this work are based on a solar desalination device with seven steps. Since oxygen is a Paramagnetic gas the moist airflow in this solar desalination could be checked by applying an external magnetic field through a solenoid. The governing equations for the problem have been discretized using the finite volume method. The effects of the applied magnetic field generated by the solenoid are investigated in terms of flow streamlines, contour plots of velocity, and pressure, both in ignoring and considering the influence of magnetic field intensity. Three different combinations of NI (N is the number of solenoid turns, and I is the electric current intensity) are examined with values of 2.5 × 10⁴, 2.5 × 10⁵, and 10 × 10⁵. For the applied magnetic field with NI = 10 × 10⁵, it has been observed that the evaporation rate reaches its maximum value in all stages of the solar desalination water slide, resulting in an increased water evaporation rate in the solar desalination device. The evaporation rate has approximately reached the maximum value of 1.02 × 10⁻¹ (kg/s) in all parts of the solar desalination device.</p></div>","PeriodicalId":553,"journal":{"name":"Experimental Techniques","volume":"48 6","pages":"991 - 1003"},"PeriodicalIF":1.5,"publicationDate":"2024-05-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140930651","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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: Nine Point Bending Test Technique for Understanding of Sintered Silver Die Bonding Failure Mechanism","authors":"","doi":"10.1007/s40799-024-00711-2","DOIUrl":"10.1007/s40799-024-00711-2","url":null,"abstract":"","PeriodicalId":553,"journal":{"name":"Experimental Techniques","volume":"48 3","pages":"393 - 393"},"PeriodicalIF":1.5,"publicationDate":"2024-04-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140799992","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Study on Velocity Distribution on Cross-Section Flow of T-Shunt","authors":"L. Fang,&nbsp;Q. Gao,&nbsp;C. Zhou,&nbsp;B. Han,&nbsp;B. Ge","doi":"10.1007/s40799-024-00709-w","DOIUrl":"10.1007/s40799-024-00709-w","url":null,"abstract":"<div><p>T-shunt is one of the commonly used components in gas-liquid two-phase flow pipeline. It has the function of separating, transmitting and carrying fluid. The junction of the T-shunt is the area of diversion and confluence in the pipeline. In this paper, we study the characteristics of the T-shunt in the cross-section of the fluid flow. A visual window is installed at the end of the experimental T-shunt section, and the fluorescence pipe’s cross-section image captured through the visual window is illuminated by the laser above the pipe. The fluid velocity field is calculated using the PIV (Particle Image Velocimetry) method and the velocity field is classified and analyzed. The result shows that there are great differences in fluid flow patterns on the cross-sections of the T-shunt at different positions, and great differences in the fluid erosion and corrosion of the pipe wall at different positions away from the T-shunt outlet.</p></div>","PeriodicalId":553,"journal":{"name":"Experimental Techniques","volume":"48 6","pages":"953 - 963"},"PeriodicalIF":1.5,"publicationDate":"2024-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140671175","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Path-Integrated X-Ray Digital Image Correlation using Synthetic Reference Images","authors":"S. S. Fayad,&nbsp;E.M.C. Jones,&nbsp;C. Winters","doi":"10.1007/s40799-024-00707-y","DOIUrl":"10.1007/s40799-024-00707-y","url":null,"abstract":"<div><p>X-rays can provide images when an object is visibly obstructed, allowing for motion measurements via x-ray digital image correlation (DIC). However, x-ray images are path-integrated and contain data for all objects between the source and detector. If multiple objects are present in the x-ray path, conventional DIC algorithms may fail to correlate the x-ray images. A new DIC algorithm called path-integrated (PI)-DIC addresses this issue by reformulating the matching criterion for DIC to account for multiple, independently-moving objects. PI-DIC requires a set of reference x-ray images of each independent object. However, due to experimental constraints, such reference images might not be obtainable from the experiment. This work focuses on the reliability of synthetically-generated reference images, in such cases. A simplified exemplar is used for demonstration purposes, consisting of two aluminum plates with tantalum x-ray DIC patterns undergoing independent rigid translations. Synthetic reference images based on the “as-designed” DIC patterns were generated. However, PI-DIC with the synthetic images suffered some biases due to manufacturing defects of the patterns. A systematic study of seven identified defect types found that an incorrect feature diameter was the most influential defect. Synthetic images were re-generated with the corrected feature diameter, and PI-DIC errors were improved by a factor of 3-4. Final biases ranged from 0.00-0.04 px, and standard uncertainties ranged from 0.06-0.11 px. In conclusion, PI-DIC accurately measured the independent displacement of two plates from a single series of path-integrated x-ray images using synthetically-generated reference images, and the methods and conclusions derived here can be extended to more generalized cases involving stereo PI-DIC for arbitrary specimen geometry and motion. This work thus extends the application space of x-ray imaging for full-field DIC measurements of multiple surfaces or objects in extreme environments where optical DIC is not possible.</p></div>","PeriodicalId":553,"journal":{"name":"Experimental Techniques","volume":"48 6","pages":"941 - 951"},"PeriodicalIF":1.5,"publicationDate":"2024-04-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s40799-024-00707-y.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140595294","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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":"Optimizing Metrological Efficiency: Comparative Analysis of Filtering Methods for 2D DIC","authors":"T. Fourest","doi":"10.1007/s40799-024-00708-x","DOIUrl":"10.1007/s40799-024-00708-x","url":null,"abstract":"<div><p>Digital Images Correlation (DIC) measures are widely used in order to calibrate models. It is very common for researchers to use filters on these measurements to improve the measurement resolution (decrease the noise level) before using them with various methodologies. However, the effects of these filters on the tradeoff between spatial resolution and measurement resolution are not fully understood. The objective of the study is to compare seven common denoising/filtering methods for 2D DIC with affine subset shape function, including image filters (Gaussian, Median), frequency filters (Lowpass Butterworth, Holoborodko), local polynomial fitting (Savitzky-Golay filter, cubic splines), and Finite Elements mapping. The proposed methodology to compare the enhancement of these methods is based on the star pattern test cases used in the DIC Challenge 2.0. Hence, this study aims to obtain a general comparison of the filtering methods as opposed to case-dependent approaches. To that end, firstly, the FOLKI-D DIC code is metrologically qualified using the DIC Challenge 2.0 methodology and test cases. Then, the filtering methods are applied to the displacements and strain maps computed with the FOLKI-D code for various DIC subset sizes and filter parameters. It is found that displacement and strain map enhancements vary significantly depending on the filter. Some methods show no improvement (or worsened tradeoff in the strain case), while others achieve similar resolution tradeoffs as DIC codes using quadratic subset shape functions. Finally, it is concluded that the filter choice significantly impacts results, with higher-order lowpass Butterworth, Savitzky-Golay, and Finite Elements mapping methods showing preference over others studied.</p></div>","PeriodicalId":553,"journal":{"name":"Experimental Techniques","volume":"48 5","pages":"921 - 934"},"PeriodicalIF":1.5,"publicationDate":"2024-04-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140595300","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Damage Evolution Model Considering Fatigue Failure Factor Under Multiaxial Non-Proportional Loading","authors":"Z. Ren,&nbsp;X. Qin,&nbsp;Q. Zhang,&nbsp;Y. Sun","doi":"10.1007/s40799-024-00706-z","DOIUrl":"10.1007/s40799-024-00706-z","url":null,"abstract":"<div><p>The Chaudonneret model cannot fully and effectively characterize the linear correlation between the strain energy density release rate and the number of cycles in the damage evolution stage of low carbon alloy steels under multiaxial non-proportional loading. In order to solve this problem, the fatigue failure process of Q355B is captured by digital image correlation technology, and the factors affecting fatigue failure under multiaxial loading are analyzed in combination with fracture morphology characteristics. Based on the concept of critical plane, a new stress combination form is introduced to reflect the failure factors, and the corresponding damage evolution model is proposed. The model considers the interaction between different stresses and can describe the damage evolution law under non-proportional loading. Compared with different types of life prediction models, the distribution range of life prediction results of the improved model under multiaxial non-proportional loading has a good correlation with the experimental values.</p></div>","PeriodicalId":553,"journal":{"name":"Experimental Techniques","volume":"48 5","pages":"905 - 920"},"PeriodicalIF":1.5,"publicationDate":"2024-04-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140595303","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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: High‑Order Time‑Domain DIC Algorithm Based on a Nonlinear Optical Flow Equation","authors":"","doi":"10.1007/s40799-024-00705-0","DOIUrl":"10.1007/s40799-024-00705-0","url":null,"abstract":"","PeriodicalId":553,"journal":{"name":"Experimental Techniques","volume":"48 2","pages":"189 - 189"},"PeriodicalIF":1.5,"publicationDate":"2024-03-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140033225","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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 Experimental Study on the Dependency of Thermal Resistance of Additively Manufactured Micro-Channel Heat Sinks on Channel Cross-Sections","authors":"A.N. Kivanani,&nbsp;S. Khalilpourazary,&nbsp;F. Mobadersani","doi":"10.1007/s40799-024-00703-2","DOIUrl":"10.1007/s40799-024-00703-2","url":null,"abstract":"<div><p>Cooling by micro-channel heat sink transfers excess heat flux in electrical devices and increases their functional capacity, reliability, and life span. In this paper, AlSi10Mg powders were employed to create four micro-channel heat sinks with cross-sections including square, rectangle, circle, and ellipse with an additive manufacturing method. To investigate the impact of micro-channel heat sink cross-sectional geometry on thermal resistance, Taguchi’s L25 orthogonal array was utilized. Reynolds number and electric power were selected to be the input parameters. The experimental tests were conducted using an experimental setup and distilled water as the working fluid in the laminar flow regime. The results obtained from the experimental tests indicated that in the range of electric power from 4 to 12 W and Reynolds numbers of 50, 100, 150, 200, and 250, the micro-channel heat sink with a square cross-section exhibits the highest heat transfer performance. Finally, an analysis of variance was conducted to study the impact of the Reynolds number and electric power factors on thermal resistance. The findings revealed the significant effect of electric power on thermal resistance in micro-channel heat sinks compared to the Reynolds number in the laminar regime. Additionally, a comparison was made with other available results.</p></div>","PeriodicalId":553,"journal":{"name":"Experimental Techniques","volume":"48 5","pages":"877 - 891"},"PeriodicalIF":1.5,"publicationDate":"2024-02-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139917726","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Integration of Discrete Wavelet and Fast Fourier Transforms for Quadcopter Fault Diagnosis","authors":"A. A. Jaber,&nbsp;L. A. Al-Haddad","doi":"10.1007/s40799-024-00702-3","DOIUrl":"10.1007/s40799-024-00702-3","url":null,"abstract":"<div><p>Due to the extensive use of Unmanned Aerial Vehicles (UAVs) and the co-evolution of current technology, a key introduction to fault detection has arisen in recent studies in order to prevent unfortunate consequences. In this study, vibration-based signals from a commercially available innovative quadcopter flying in hover mode are collected using a vibration accelerometer, a data acquisition device, and a laptop. An ADXL335 accelerometer is fixed on the center of the drone where the centerlines of the four blades intersect. The superposition of numerous vibration arrangements over identical spectra hinders the ability to analyze the spectral data in the manner required to locate any framework's discrete vibration. This work presents a technique for separating a synthesized vibration signal towards discrete vibrations and other extraneous vibrations of a structure utilizing the Discrete Wavelet Transform (DWT) integrated with the Fast Fourier Transform (FFT). The research article findings in this study demonstrate the reliability and applicability of specific categories of discrete vibrations that are sorted out during the structural change evaluation to develop the best feasible strategy for removing the undesired and unanticipated vibration components and noise. The methodology demonstrated in this paper has the potential for practical application to multirotor UAVs in general.</p></div>","PeriodicalId":553,"journal":{"name":"Experimental Techniques","volume":"48 5","pages":"865 - 876"},"PeriodicalIF":1.5,"publicationDate":"2024-02-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139945715","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}