{"title":"Small-Scale Wind Tunnel for the Investigation of the Influence of Environmental Conditions on the Performance of Building Materials","authors":"R. Cacciotti, B. Wolf, M. Macháček","doi":"10.1007/s40799-023-00672-y","DOIUrl":"10.1007/s40799-023-00672-y","url":null,"abstract":"<div><p>Climate significantly affects the performance of building materials and its changing patterns are posed to increasingly exacerbate the projected impacts. Prevention strategies are indeed necessary to ensure avoiding excessive degradation and serious damage to the built environment. In this context, innovative and accessible methodologies and tools are required to investigate and characterize the interaction between material properties and climatic factors. This paper presents an innovative device for the simulation of natural ventilation, relative humidity and temperature fluctuations and for evaluating the performance of building materials subjected to different environmental scenarios. The presented results include the design, construction and validation of a small-scale wind tunnel (2 m × 1.8 m ca. vertical orientation). Key findings outline the adequacy of the tool in reproducing a stable, quality airflow with the following characteristics: achievable operational airflow speed ranges between 0.2 and 0.7 m/s, safe operational temperature is included between 10℃ and 35℃ and allowable operational relative humidity varies between 30 and 99%. Advantages and limitations for laboratory applications are outlined in the paper and future work is also suggested.</p></div>","PeriodicalId":553,"journal":{"name":"Experimental Techniques","volume":"48 3","pages":"485 - 499"},"PeriodicalIF":1.5,"publicationDate":"2023-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135825696","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}
H. E. Lakache, A. May, R. Badji, S. E. Benhammouda, S. Ramtani
{"title":"The Impact of the Rotary Friction Welding Pressure on the Mechanical and Microstructural Characteristics of Friction Welds Made of the Alloys TiAl6V4 and 2024 Aluminum","authors":"H. E. Lakache, A. May, R. Badji, S. E. Benhammouda, S. Ramtani","doi":"10.1007/s40799-023-00671-z","DOIUrl":"10.1007/s40799-023-00671-z","url":null,"abstract":"<div><p>This paper is a study of the mechanical properties and microstructures of the similar friction weld joints (TiAl6V4 and AA2024) using a servo-controlled Rotary Friction Welding (RFW) system. The friction welding operations were performed with seven different values of the friction pressure in the range of 2–14 MPa. The temperature is recorded during friction welding tests using k-type thermocouples. Tensile tests and microhardness measurements were carried out to obtain the mechanical properties of the friction weld joints. Microstructural changes of individual zone of the friction welds were investigated using an optical microscope (OM), and the fracture surfaces were observed using a scanning electron microscope (SEM). For AA2024, the fracture occurs most frequently in the central zone, resulting in lower tensile strength values, while for TiAl6V4, the fracture is occurs outside the friction weld interface, indicating that the friction weld joint is more resistant than the base metal. Microscopic analysis of the fracture surfaces of the AA2024 samples revealed diverse morphologies, with rough cupular surfaces predominating, indicating a dominant ductile fracture mode. Similarly, TiAl6V4's friction welded specimen also exhibited cupules of various sizes across its surface, primarily associated with a ductile fracture mode. Overall, the optimal friction pressure values (respectively 8 and 10 MPa for TiAl6V4 and AA2024) correspond to the highest values of the mechanical properties.</p></div>","PeriodicalId":553,"journal":{"name":"Experimental Techniques","volume":"48 3","pages":"473 - 484"},"PeriodicalIF":1.5,"publicationDate":"2023-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135982367","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: Deflection Measurement of Bridge Using Images Captured Under the Bridge by Sampling Moiré Method","authors":"","doi":"10.1007/s40799-023-00673-x","DOIUrl":"10.1007/s40799-023-00673-x","url":null,"abstract":"","PeriodicalId":553,"journal":{"name":"Experimental Techniques","volume":"47 5","pages":"939 - 939"},"PeriodicalIF":1.6,"publicationDate":"2023-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"24849820","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":"Effect of Particle Concentration and Size on the Time-Averaged Velocity of Oil","authors":"C. Bin, L. Ge","doi":"10.1007/s40799-023-00669-7","DOIUrl":"10.1007/s40799-023-00669-7","url":null,"abstract":"<div><p>\u0000 It is of great significance for the safe operation of oil equipment to know the influence of particle size and concentration on the time-averaged velocity of oil. The oil with different particle size and concentration were tested using particle image velocimetry (PIV) measurement technology in an exceedingly square tube, the instant velocity vector information of the oil flow field was non-inheritable, and the time-averaged velocity distributions were analyzed along the flow direction and normal direction. The results showed that the flow time-flow-averaged velocity of the oil-containing particles is a quasi-parabola shape along the normal direction, and its variation amplitude increases with the decrease of the particle concentration and reaches the highest value when the particle size is 25 μm. The normal time-flow-averaged velocity has the extreme value along the normal direction when the particle concentration is low, and the variation range is large; when the normal position ranges from 0 to 0.2 and above 0.2, the unidirectional of the normal time-flow-averaged velocity of the oil is reversed. The distribution of the flow time-normal-averaged velocity along the flow direction is also a quasi-parabolic shape, and its variation amplitude is more uneven with the decrease of particle concentration. Similarly, the distribution of the normal time-normal-averaged velocity along the flow direction increases with the decrease of particle concentration, and this trend is more obvious when the particle size is 25 μm. These changes make the motion characteristics of the oil unstable, which is not conducive to the stable realization of the function of the oil equipment, so the presence of particles in the oil has an important impact on the motion characteristics of the oil and even the accurate and reliable operation of the equipment.</p></div>","PeriodicalId":553,"journal":{"name":"Experimental Techniques","volume":"48 3","pages":"461 - 471"},"PeriodicalIF":1.5,"publicationDate":"2023-08-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75988186","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}
M. Pourrousta, M. M. Larimi, M. Biglarian, P. Hedayati
{"title":"Liquid Jet Breakup and Penetration in a Gas Cross-Flow -An Experimental Study","authors":"M. Pourrousta, M. M. Larimi, M. Biglarian, P. Hedayati","doi":"10.1007/s40799-023-00668-8","DOIUrl":"10.1007/s40799-023-00668-8","url":null,"abstract":"<div><p>In the present study, an experimental platform is developed to study the behavior of the injected jet in a gas cross-flow applicable to different categories of fluid mechanics such as combustion. In all tests, water and air are used as jet and cross-flow gas, respectively. The main target of this work is to cover the higher range of momentum ratios and Weber numbers for the presentation of a more accurate equation for jet trajectory. To achieve a desirable scale of experiments, the range of momentum ratio is considered from 5 to 211 and the Weber number of gasses in all tests is between 1.1–19.1. For data mining and measurements, the shadowgraph method is used. It is shown that by increasing the momentum ratio (about 84%), the breakup point height is increased (about 94%). Three different types of breakups were observed in the tests. It observed that as the Weber number increases, the type of jet column mechanism changes. It also revealed that the type of breakup mechanism would not have a significant effect on the jet trajectory. In addition, it demonstrated that the momentum ratio parameter would have a decisive role in the direction of jet motion, and as the momentum ratio increases, the jet column height increases. Finally, an equation for the trajectory of jet flight under all test conditions is presented.</p></div>","PeriodicalId":553,"journal":{"name":"Experimental Techniques","volume":"48 3","pages":"449 - 459"},"PeriodicalIF":1.5,"publicationDate":"2023-08-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88016123","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":"Numerical and Experimental Buckling Analysis for Circular Plates","authors":"H. Akbulut, M. F. Bingöl","doi":"10.1007/s40799-023-00667-9","DOIUrl":"10.1007/s40799-023-00667-9","url":null,"abstract":"<div><p>This paper deals with the determination of numerical and experimental buckling loads for circular plates. In the study, plates made of isotropic material and laminated composites were taken into consideration. For the experimental part of the study, a buckling apparatus for circular plates (BACIP) was designed and manufactured to apply radial compression on plates simply supported along the outer edge, which was the most important aspect of the study. Experimental buckling loads were determined by connecting this apparatus to a tension machine. ANSYS software based on the Finite Element Method (FEM) and the analytical buckling load formula found in textbooks were also used for the determination of the numerical and analytical buckling loads. The effects of parameters such as plate thickness, number of layers, cutout sizes, and so on on critical buckling loads were investigated within the scope of the work. Comparisons of analytical, theoretical and experimental buckling loads were presented in both graphical and tabular form. The results of the experimental and theoretical buckling were found to be comparatively compatible.</p></div>","PeriodicalId":553,"journal":{"name":"Experimental Techniques","volume":"48 3","pages":"439 - 448"},"PeriodicalIF":1.5,"publicationDate":"2023-08-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84493630","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}
W.I.I.W.I. Mirza, A. Kyprianou, T. A.N. da Silva, M.N.A. Rani
{"title":"Frequency Based Substructuring and Coupling Enhancement Using Estimated Rotational Frequency Response Functions","authors":"W.I.I.W.I. Mirza, A. Kyprianou, T. A.N. da Silva, M.N.A. Rani","doi":"10.1007/s40799-023-00670-0","DOIUrl":"10.1007/s40799-023-00670-0","url":null,"abstract":"<div><p>Accurate estimation of rotational frequency response functions (FRFs) is an essential element of successful structural coupling. It is well known that the experimental estimation of structural excitations is very difficult with current technology. This paper proposes a scheme to improve the performance of the frequency-based substructuring (FBS) method by estimating unmeasured FRFs, including those corresponding to rotational degrees of freedom, from a set of experimentally determined translational FRFs. More specifically, the modal parameters extracted by modal analysis (EMA) from the experimentally determined FRFs are used for model updating, modal expansion and FRF synthesis. For this purpose, an approximate modelling approach is proposed, where a simplified and approximate finite element model (ASFE) is developed and updated to accurately reproduce the experimental responses. A modal expansion basis is then constructed from the ASFE to expand the mode shapes using the system equivalent reduction and expansion process (SEREP). FRF synthesis is then used to derive unmeasured translational and rotational FRFs. The synthesised FRFs within the frequency range of interest agree well with the experimental FRFs. The synthesised full FRF matrix is then used with the FBS method to derive the response model for the coupled structure in a bottom-up modelling approach.</p></div>","PeriodicalId":553,"journal":{"name":"Experimental Techniques","volume":"48 3","pages":"423 - 437"},"PeriodicalIF":1.5,"publicationDate":"2023-08-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77135805","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":"Model Validation of Rigid Body Tilting of Deformed Spinning Discs with Spline-Guided Constraints","authors":"J. Xue, B. Ma, M. Chen, L. Yu, L. Zheng","doi":"10.1007/s40799-023-00657-x","DOIUrl":"10.1007/s40799-023-00657-x","url":null,"abstract":"<div><p>This paper analyzes the rigid body tilting of the spinning disc with a spline-guided boundary condition. Firstly, a comprehensive dynamic model of the flat disc is built to illustrate the general forces during rigid body tilting. On this basis, the tilting model of deformed discs is derived by introducing the shape function. Also, the model accounts for friction at the spline interface, constraints on the tilting angle, and the impact force experienced with the boundary during the tilting motion. A test rig is designed to evaluate the accuracy of the model, and the similarity between experimental and simulated signals is compared in both the time domain and frequency domain. The results show that the rotational speed increases the spectral amplitude associated with boundary impact, whereas disc deformation contributes to variations in the frequency bands of spectral peaks, resulting in the emergence of spectral peaks at higher frequencies.</p></div>","PeriodicalId":553,"journal":{"name":"Experimental Techniques","volume":"48 3","pages":"409 - 421"},"PeriodicalIF":1.5,"publicationDate":"2023-07-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73800488","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}
K. Wakamoto, K. Fuji, T. Otsuka, K. Nakahara, T. Namazu
{"title":"Nine Point Bending Test Technique for Understanding of Sintered Silver Die Bonding Failure Mechanism","authors":"K. Wakamoto, K. Fuji, T. Otsuka, K. Nakahara, T. Namazu","doi":"10.1007/s40799-023-00664-y","DOIUrl":"10.1007/s40799-023-00664-y","url":null,"abstract":"<p>The Sintered silver (s–Ag) die degradation is commonly evaluated by thermal shocked test (TST), which evaluates the material’s durability against a heating/cooling cycle. Materials with different coefficient of thermal expansion (CTE) give rise to thermal out-of-plane deformation surrounding the bonding part, which deteriorates s–Ag die part by repeated thermal and mechanical stress during TST. For the safe and reliable design of s–Ag die toward long-term durability, the contribution of thermal and mechanical stresses to degradation should be understood separately. Clarify the overall s–Ag die degradation mechanism during TST compared to the new mechanical bending test that can apply out-of-plane deformation. The authors propose a new mechanical bending test technique, called the nine-point bending (NBT) test, which can provide out-of-plane deformation with a s–Ag die-attached specimen as TST like. By comparing NBT and TST, the degradation mechanism of the s–Ag die-attach element can be understood from both thermal and mechanical aspects. In scanning acoustic tomography (SAT) analysis, a similar degradation ratio between NBT and TST is obtained, which indicates that mechanical stress plays a significant role in deteriorating s–Ag die layer in TST. After 1000 cycles, however, cracking and s–Ag material aging coexist in TST only, destabilizing s–Ag die fracture. s–Ag main degradation cause in TST is clarified with mechanical stress by comparing NBT. In addition, thermally material aging destabilized the s–Ag degradation during TST.</p>","PeriodicalId":553,"journal":{"name":"Experimental Techniques","volume":"48 3","pages":"399 - 408"},"PeriodicalIF":1.5,"publicationDate":"2023-07-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s40799-023-00664-y.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74139435","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":"Locating Impacts Through Structural Vibrations Using the FEEL Algorithm Without a Known Input Force","authors":"B. T. Davis, Y. MejiaCruz","doi":"10.1007/s40799-023-00662-0","DOIUrl":"10.1007/s40799-023-00662-0","url":null,"abstract":"<div><p>Floor vibration-based methods to track human activity are becoming popular for applications in healthcare monitoring, security, and occupant detection. Popular techniques such as time of arrival (TOA) methods face wave dispersion and multiple-path fading challenges for localization. Data-driven methodologies such as the FEEL Algorithm rely exclusively on the system dynamic properties, an advantage over other methods. However, FEEL’s calibration process requires recording force input to the structure, which can become labor-intensive and time-consuming for applications that require a high localization accuracy and does not require force estimates. An alternative approach is proposed to use the system’s acceleration response exclusively, creating an output-to-output transfer function. This modification was tested against the 3575 impact Human-Induced Vibration Benchmark dataset containing seven impact types across five locations, the same dataset FEEL was originally developed with. The results demonstrated the acceleration-calibrated FEEL effectiveness with 99.9% localization accuracy compared to force-calibrated FEEL’s accuracy of 96.4%.</p></div>","PeriodicalId":553,"journal":{"name":"Experimental Techniques","volume":"48 2","pages":"359 - 368"},"PeriodicalIF":1.5,"publicationDate":"2023-07-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91082492","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}