Experimental Mechanics, Instrumentation and Metrology II

A special issue of Applied Sciences (ISSN 2076-3417). This special issue belongs to the section "Mechanical Engineering".

Deadline for manuscript submissions: closed (31 December 2023) | Viewed by 5616

Special Issue Editors

1. Polytechnic Institute of Lisbon (IPL), 1959-007 Lisboa, Portugal
2. Research and Development Unit for Mechanical and Industrial Engineering (UNIDEMI), 1070-312 Lisboa, Portugal
3. Navy Research Center (CINAV), 2810-001 Almada, Portugal
Interests: mechanics of fracture; instrumentation; mechanical tests; experimental stress analysis; mechanical behavior of materials; structural durability; manufacturing processes; processes and maintenance management
Special Issues, Collections and Topics in MDPI journals
National Laboratory for Civil Engineering (LNEC), Av. do Brasil 101, 1700-066 Lisboa, Portugal
Interests: metrology; quality systems; numerical simulation; applied mathematics; modelling; testing; accreditation
Special Issues, Collections and Topics in MDPI journals
National Laboratory for Civil Engineering (LNEC), Av. do Brasil 101, 1700-066 Lisboa, Portugal
Interests: metrology; quality; instrumentation; optics
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

Experimental mechanics, instrumentation and metrology is a highly multidisciplinary research field. It combines technological and scientific methods to produce, model and understand physical phenomena. Submissions are invited for original research, review articles and case studies. We hope that this collection of papers will inspire those interested in experimental mechanics, instrumentation and metrology.

Theoretical and experimental contributions, original and review studies, and industrial and university research will be welcome. The main topics include, but are not limited to, the following:

prototyping and full-scale testing; NEMS and MEMS technologies; instrumentation; data acquisition and processing; metrology; monitoring; experimental tests; measurements; optimum experimental techniques; cases studies.

Prof. Dr. Teresa Leonor Martins Morgado
Dr. Álvaro Silva Ribeiro
Dr. Luís Filipe Lages Martins
Guest Editors

Manuscript Submission Information

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Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Applied Sciences is an international peer-reviewed open access semimonthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2400 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • instrumentation
  • metrology
  • measurements
  • flowmeter
  • nems
  • mems
  • monitoring
  • data acquisition
  • experimental techniques
  • data processing
  • reliability
  • monte carlo method
  • uncertainty
  • calibration
  • test bench
  • full-scale testing
  • prototyping testing

Published Papers (4 papers)

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Research

22 pages, 20755 KiB  
Article
The Calibration Process and Setting of Image Brightness to Achieve Optimum Strain Measurement Accuracy Using Stereo-Camera Digital Image Correlation
by Martin Hagara, Róbert Huňady, Pavol Lengvarský, Michal Vocetka and Peter Palička
Appl. Sci. 2023, 13(17), 9512; https://doi.org/10.3390/app13179512 - 22 Aug 2023
Viewed by 581
Abstract
Combining the drilling method with the digital image correlation (DIC) method is becoming more common to speed up the measurement and evaluate the strains relieved at several locations. However, to obtain the most accurate results, it is necessary to be aware of the [...] Read more.
Combining the drilling method with the digital image correlation (DIC) method is becoming more common to speed up the measurement and evaluate the strains relieved at several locations. However, to obtain the most accurate results, it is necessary to be aware of the influence of possible aspects that could adversely affect the results of the strain/stress analysis carried out using DIC. The paper describes several analyses to assess the influence of the 3D DIC system’s calibration procedure for strain/stress analysis of the specimen with a hole loaded with four different levels of tensile force. In addition, the paper also deals with the analysis of the influence of the image brightness, which was modified by changing the exposure time of the cameras. Based on the results of strain/stress analyses performed on small areas (approx. 25 × 25 mm) of a specimen with a hole by a stereo-camera DIC system, it can be concluded that both analysed factors can negatively influence the results. The most accurate results are ensured using the calibration target of very high manufacturing precision sized similarly to the field of view observed in correlation mode. The optimal image brightness is adjusted when the mean grey value of the image is from the range of 56 up to 171 with as evenly distributed image point intensities as possible. Full article
(This article belongs to the Special Issue Experimental Mechanics, Instrumentation and Metrology II)
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16 pages, 4124 KiB  
Article
Hydraulic Prototype Observation Tests on Reconstructed Energy Dissipation Facilities
by Hai Wei, Kaiyun Tao, Yongqin Luo, Bingyue Song, Mingming Wang and Juncai Xu
Appl. Sci. 2023, 13(10), 6216; https://doi.org/10.3390/app13106216 - 19 May 2023
Viewed by 948
Abstract
In order to assess the effectiveness of reconstructed energy dissipation facilities (EDFs) in open channels at hydropower stations, hydraulic prototype observation (HPO) tests are conducted to investigate the characteristics of discharge flow and the dynamic response of hydraulic structures during sluice opening periods. [...] Read more.
In order to assess the effectiveness of reconstructed energy dissipation facilities (EDFs) in open channels at hydropower stations, hydraulic prototype observation (HPO) tests are conducted to investigate the characteristics of discharge flow and the dynamic response of hydraulic structures during sluice opening periods. While hydraulic model tests (HMTs) are commonly utilized in laboratory settings to study these characteristics, experimental conditions cannot fully replicate the real-world operations of such structures. HPO tests are employed to examine flow patterns, free water surface fluctuations, and pulsating pressure changes in open channels under varying flood discharge conditions (FDCs). Flow patterns in open channels are recorded via video; free water surface fluctuations are measured using total-station and laser rangefinder instruments; and pulsating pressure is monitored with pressure sensors and data collection systems. Flow pattern observations concentrate on addressing adverse water flow phenomena, such as turbulence, surging, and backflow. The examination of free water surface fluctuations aims to verify whether the height of the guide wall along the open channel fulfills the necessary requirements and assess the effectiveness of energy dissipation of the EDF. To comprehend the variations in pulsating pressure within the continuous sill and the base slab, nine measurement points were established across three sections perpendicular to the continuous sill’s axis on three distinct elevation levels. Additionally, three measurement points were positioned on the reinforced base slab along the open channel’s axis. The findings indicate that the impact on the continuous sill caused by discharging water is more severe when the discharge rate of a single sluice gate reaches 500 m3/s than in other FDCs. To ensure the safe operation of open channels during flood discharge, the discharge rate for each sluice gate should be reduced to 250 m3/s. The dominant pulsation induced by discharge flow falls within the low-frequency range, resulting in minimal adverse effects on the stilling basin and guide wall. The flow pattern within the stilling basin remains stable under various FDCs, with no significant adverse hydraulic phenomena observed. Parameters, including free water surface fluctuations and pulsating pressure variations, lie within acceptable ranges. These observations suggest that the arrangement of the reconstructed energy dissipation facilities is generally effective following technical reconstruction. Full article
(This article belongs to the Special Issue Experimental Mechanics, Instrumentation and Metrology II)
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26 pages, 15102 KiB  
Article
Experimental Development of Composite Bicycle Frame
by Milan Dvořák, Tomáš Ponížil, Viktor Kulíšek, Nikola Schmidová, Karel Doubrava, Bohumil Kropík and Milan Růžička
Appl. Sci. 2022, 12(16), 8377; https://doi.org/10.3390/app12168377 - 22 Aug 2022
Cited by 2 | Viewed by 2145
Abstract
This article focuses on the development of a carbon composite bicycle frame using various experimental methods of structural analysis. Two types of frame specimen were used. The complete frame specimen was tested in accordance with ISO test load cases with the addition of [...] Read more.
This article focuses on the development of a carbon composite bicycle frame using various experimental methods of structural analysis. Two types of frame specimen were used. The complete frame specimen was tested in accordance with ISO test load cases with the addition of an ergometer test in order to refine the operational strain envelope of such a frame. Resistive strain gauges and optical Fiber Bragg Grating (FBG) sensors were used for this analysis. The FBG sensors were embedded inside the head tube joints during the manufacturing process. The head connection was designed as a geometrically precise form–connection of wound composite tubes, reinforced with a wrap of high-strength unidirectional carbon tapes and carbon fabrics. Additional structural strength laboratory tests were conducted using simplified frame specimens, in order to evaluate the range of the limit case strain ranges. The digital image correlation method was used for the evaluation of the strain distribution in the head tube area. Resistive strain gauges were used for local strain analysis in critical areas. The acoustic emission method was used to detect structural defects before they could influence the stiffness response of the frame. It was found that the joints of the frame tubes are crucial for the strength and safety of the frame. Therefore, attention was also focused on the strengthening of the head tube joint, and on its experimental verification. A positive effect on the strength of the reinforced frame was found by doubling the thickness of the carbon fabric in the head tube joint area. Full article
(This article belongs to the Special Issue Experimental Mechanics, Instrumentation and Metrology II)
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22 pages, 2629 KiB  
Article
A Statistical Approach in the Analysis of Geometrical Product Specification during the Cold Tube Drawing Process
by Ladislav Morovic, Michaela Kritikos, Daynier Rolando Delgado Sobrino, Jozef Bilik, Robert Sobota and Maria Kapustova
Appl. Sci. 2022, 12(2), 676; https://doi.org/10.3390/app12020676 - 11 Jan 2022
Cited by 3 | Viewed by 1111
Abstract
Cold tube drawing provides higher accuracy compared to hot approaches. The process can be used to reduce the dimensions of tubes, and depending on the reduction size, the wall thickness of these may be subject to changes. In the process, any form of [...] Read more.
Cold tube drawing provides higher accuracy compared to hot approaches. The process can be used to reduce the dimensions of tubes, and depending on the reduction size, the wall thickness of these may be subject to changes. In the process, any form of variability provoked by external factors is highly sensitive, given that the resulting tubes are often the final step in tube production. This paper focused on the evaluation of the influence of pre-tube factors on key variables after the drawing process, i.e., the final roundness, outer diameter, and wall thickness of the tubes. For these purposes, a factorial design with fixed factors was implemented. It was also a goal to investigate if the single-pass type of drawing would guarantee good statistical results potentially leading to significant time and financial reductions. The measurements were executed in the machine ZEISS CenterMax. The statistical analysis took place on Minitab 19. The results prove that most factors, and their interactions, significantly impacted the response variables, leading the authors to understand that a single-pass approach would not properly work under the conditions defined for the experimentation. These results also allow for reflection on the causes and necessary measures related to lubrication, technological heritage, and quality that would impact the results themselves. Full article
(This article belongs to the Special Issue Experimental Mechanics, Instrumentation and Metrology II)
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