Low-frame-rate single camera system for 3D full-field high-frequency vibration measurements

Barone, Sandro; Neri, Paolo; Paoli, Alessandro; Razionale, Armando Viviano

doi:10.1016/j.ymssp.2019.01.016

Cited by 49 publications

(24 citation statements)

References 27 publications

(33 reference statements)

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“…Here, the square facet with unique features is used as a reference image, while a correlation function is used for searching the corresponding facet and defining a displacement vector d as the specimen deforms 53 . It is of interest to point out that recently, to reduce the devices required to perform 3D‐DIC, systems using a single camera for performing stereo measurement have been proposed by integrating two planar mirrors to measure vibrations with an amplitude as small as 0.01 mm 54 …”

Section: Background Of Optical Sensing Thechniquesmentioning

confidence: 99%

Multicamera measurement system to evaluate the dynamic response of utility‐scale wind turbine blades

et al. 2020

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Wind turbine blade certification requires static and fatigue testing at a large-scale facility similar to the Wind Technology Testing Center (WTTC) located in Charlestown, Massachusetts. Usually, these tests are conducted by using wire-based sensors such as strain gages, accelerometers, and string potentiometers. These systems are expensive, require a time-consuming installation (e.g., up to 3 weeks and $35 k-$50 k for a strain gage system on a 55-m-long blade), are difficult to deploy on large-sized structures, require additional instrumentations (e.g., power amplifiers and data acquisition systems), and produce results only at a handful of a discrete number of measurement points. In this study, a multicamera measurement system is implemented and experimentally evaluated to obtain full-field displacement and strain over a~12-m-long portion of a~60-m utility-scale wind turbine blade. The proposed system has the potential to streamline the certification process by reducing the blade's preparation and sensor installation cost and time to a few hundreds of dollars (for painting equipment) and a few days for preparing the surface of the blade for the test. Furthermore, operational modal analysis was used in conjunction with the multicamera system to estimate the natural frequencies and mode shapes of the wind turbine blade. The obtained results have shown that the proposed approach can detect in-plane displacement as low as 0.2 mm, mechanical strain with an error below 3% when compared with measurement performed using strain gages, and the first five natural frequencies with an error below 2% when compared with data recorded using traditional wire-based accelerometers. This paper presents these results and provides a summary of the strengths and weaknesses of the proposed optical measurement approach in the context of streamlining the blade certification/testing process and performing vision-based structural dynamic measurements on large-scale structures. K E Y W O R D Sdigital image correlation, fatigue tests, operational modal analysis, stitched field of view, structural health monitoring, wind turbine blades

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Section: Background Of Optical Sensing Thechniquesmentioning

confidence: 99%

Multicamera measurement system to evaluate the dynamic response of utility‐scale wind turbine blades

et al. 2020

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“…Vibration measurements can be performed by a vibration analyzer [ 138 ] or digital image correlation (DIC) by cameras [ 139 ]. In this way, amplitude in the different range of frequency or displacement magnitude against the time in a certain frequency is achievable.…”

Section: Performance Evaluationmentioning

confidence: 99%

Toward Polymeric and Polymer Composites Impeller Fabrication

et al. 2021

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Impellers are referred to as a core component of turbomachinery. The use of impellers in various applications is considered an integral part of the industry. So, increased performance and the optimization of impellers have been the center of attention of a lot of studies. In this regard, studies have been focused on the improvement of the efficiency of rotary machines through aerodynamic optimization, using high-performance materials and suitable manufacturing processes. As such, the use of polymers and polymer composites due to their lower weight when compared to metals has been the focus of studies. On the other hand, methods of the manufacturing process for polymer and polymer composite impellers such as conventional impeller manufacturing, injection molding and additive manufacturing can offer higher economic efficiency than similar metal parts. In this study, polymeric and polymer composites impellers are discussed and conclusions are drawn according to the manufacturing methods. Studies have shown promising results for the replacement of polymers and polymer composites instead of metals with respect to a suitable temperature range. In general, polymers showed a good ability to fabricate the impellers, however in more difficult working conditions considering the need for a substance with higher physical and mechanical properties necessitates the use of composite polymers. However, in some applications, the use of these materials needs further research and development.

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“…For this reason, the accuracy of passive stereo-vision ranges from 0.2% for surfaces with good texture to 9.4% for texture-less surfaces [ 17 ]. In some cases, where possible, the surface texture can be enhanced by spraying speckle patterns on the target surface, and stereo digital image correlation techniques are used to find correspondences between left and right images [ 33 , 34 , 35 ].…”

Section: 3d Scanning Technologiesmentioning

confidence: 99%

Sensor Architectures and Technologies for Upper Limb 3D Surface Reconstruction: A Review

Paoli

Neri

Razionale

et al. 2020

Sensors

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3D digital models of the upper limb anatomy represent the starting point for the design process of bespoke devices, such as orthoses and prostheses, which can be modeled on the actual patient’s anatomy by using CAD (Computer Aided Design) tools. The ongoing research on optical scanning methodologies has allowed the development of technologies that allow the surface reconstruction of the upper limb anatomy through procedures characterized by minimum discomfort for the patient. However, the 3D optical scanning of upper limbs is a complex task that requires solving problematic aspects, such as the difficulty of keeping the hand in a stable position and the presence of artefacts due to involuntary movements. Scientific literature, indeed, investigated different approaches in this regard by either integrating commercial devices, to create customized sensor architectures, or by developing innovative 3D acquisition techniques. The present work is aimed at presenting an overview of the state of the art of optical technologies and sensor architectures for the surface acquisition of upper limb anatomies. The review analyzes the working principles at the basis of existing devices and proposes a categorization of the approaches based on handling, pre/post-processing effort, and potentialities in real-time scanning. An in-depth analysis of strengths and weaknesses of the approaches proposed by the research community is also provided to give valuable support in selecting the most appropriate solution for the specific application to be addressed.

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Low-frame-rate single camera system for 3D full-field high-frequency vibration measurements

Cited by 49 publications

References 27 publications

Multicamera measurement system to evaluate the dynamic response of utility‐scale wind turbine blades

Multicamera measurement system to evaluate the dynamic response of utility‐scale wind turbine blades

Toward Polymeric and Polymer Composites Impeller Fabrication

Sensor Architectures and Technologies for Upper Limb 3D Surface Reconstruction: A Review

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