Three dimensional（3D） displacements, which can be translated further into 3D strain, are key parameters tor design, manufacturing and quality control. Using different optical setups, phase-shift methods, and algorit...Three dimensional（3D） displacements, which can be translated further into 3D strain, are key parameters tor design, manufacturing and quality control. Using different optical setups, phase-shift methods, and algorithms, several different 3D electronic speckle pattern interferometry（ESPl） systems for displacement and strain measurements have been achieved and commercialized. This paper provides a review of the recent developments in ESPI systems for 3D displacement and strain measurement. After an overview of the fundamentals of ESP! theory, temporal phase-shift, and spatial phase-shift techniques, 3D deformation measurements by the temporal phase-shift ESPI system, which is suited well for static measurement, and by the spatial phase-shift ESPI system, which is particularly useful for dynamic measurement, are discussed. For each method, the basic theory, a brief derivation and different optical layouts are presented. The state of art application, potential and limitation of the ESPI systems are shown and demonstrated.展开更多
A new and easy-to-fabricate strain sensor has been developed,based on fiber Bragg grating(FBG)technology embedded into a thermoplastic polyurethane filament using a 3-dimensional(3D)printer.Taking advantage of the fle...A new and easy-to-fabricate strain sensor has been developed,based on fiber Bragg grating(FBG)technology embedded into a thermoplastic polyurethane filament using a 3-dimensional(3D)printer.Taking advantage of the flexibility and elastic properties of the thermoplastic polyurethane material,the embedding of the FBG provides durable protection with enhanced flexibility and sensitivity,as compared to the use of a bare FBG.Results of an evaluation of its performance have shown that the FBG sensors embedded in this way can be applied effectively in the measurement of strain,with an average wavelength responsivity of 0.0135 nm/cm of displacement for tensile strain and -0.0142 nm/cm for compressive strain,both showing a linearity value of up to 99%.Furthermore,such an embedded FBG-based strain sensor has a sensitivity of~1.74 times greater than that of a bare FBG used for strain measurement and is well protected and suitable for in-the-field use.It is also observed that the thermoplastic polyurethane based(TPU-based)FBG strain sensor carries a sensitivity value of~2.05 times higher than that of the polylactic acid based(PLA-based)FBG strain sensor proving that TPU material can be made as the material of choice as a“sensing”pad for the FBG.展开更多
基金supported by National Natural Science Foundation of China(Grant Nos.51275054,51075116)
文摘Three dimensional（3D） displacements, which can be translated further into 3D strain, are key parameters tor design, manufacturing and quality control. Using different optical setups, phase-shift methods, and algorithms, several different 3D electronic speckle pattern interferometry（ESPl） systems for displacement and strain measurements have been achieved and commercialized. This paper provides a review of the recent developments in ESPI systems for 3D displacement and strain measurement. After an overview of the fundamentals of ESP! theory, temporal phase-shift, and spatial phase-shift techniques, 3D deformation measurements by the temporal phase-shift ESPI system, which is suited well for static measurement, and by the spatial phase-shift ESPI system, which is particularly useful for dynamic measurement, are discussed. For each method, the basic theory, a brief derivation and different optical layouts are presented. The state of art application, potential and limitation of the ESPI systems are shown and demonstrated.
基金financially supported by a Newton Fund Impact Scheme under the Newton-Ungku Omar Fund Partnership(Grant No.IF022-2020)funded by the UK Department for Business,Energy and Industrial Strategy and Malaysian Industry-Government Group for High Technology(MIGHT)and delivered by the British Council and MIGHT+1 种基金the support from University of Malaya(Grant Nos.RK021-2019 and TOP100PRC)the support from the Royal Academy of Engineering.
文摘A new and easy-to-fabricate strain sensor has been developed,based on fiber Bragg grating(FBG)technology embedded into a thermoplastic polyurethane filament using a 3-dimensional(3D)printer.Taking advantage of the flexibility and elastic properties of the thermoplastic polyurethane material,the embedding of the FBG provides durable protection with enhanced flexibility and sensitivity,as compared to the use of a bare FBG.Results of an evaluation of its performance have shown that the FBG sensors embedded in this way can be applied effectively in the measurement of strain,with an average wavelength responsivity of 0.0135 nm/cm of displacement for tensile strain and -0.0142 nm/cm for compressive strain,both showing a linearity value of up to 99%.Furthermore,such an embedded FBG-based strain sensor has a sensitivity of~1.74 times greater than that of a bare FBG used for strain measurement and is well protected and suitable for in-the-field use.It is also observed that the thermoplastic polyurethane based(TPU-based)FBG strain sensor carries a sensitivity value of~2.05 times higher than that of the polylactic acid based(PLA-based)FBG strain sensor proving that TPU material can be made as the material of choice as a“sensing”pad for the FBG.
