Uncertainty Analysis of an Optoelectronic Strain Measurement System for Flywheel Rotors

The strain in a fast spinning carbon fiber flywheel rotor is of great interest for condition monitoring, as well as for studying long-term aging effects in the carbon fiber matrix. Optoelectronic strain measurement is a contactless measurement principle where a special reflective pattern is applied to the rotor which is scanned by a stationary optical setup. It does not require any active electronic components on the rotor and is suited for operation in a vacuum. In this paper, the influences of the key parts comprising the optoelectronic strain measurement are analyzed. The influence of each part on the measurement result including the uncertainty is modeled. The total uncertainty, as well as each part’s contribution is calculated. This provides a valuable assessment of requirements for component selection, as well as tolerances of mechanical parts and processes to reach a final target measurement uncertainty or to estimate the uncertainty of a given setup. We have shown that the edge quality of the special reflective pattern has the strongest influence, and how to improve it. Considering all influences, it is possible to measure strain with an uncertainty of less than 1% at a rotation speed of 500Hz.

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Experimental Investigation of Self-Sensing Carbon Fiber Reinforced Cementitious Composite for Strain Measurement of an RC Portal Frame

International Journal of Distributed Sensor Networks ◽

10.1155/2015/531069 ◽

2015 ◽

Vol 11 (11) ◽

pp. 531069 ◽

Cited By ~ 7

Author(s):

Fang-Yao Yeh ◽

Kuo-Chun Chang ◽

Wen-Cheng Liao

Keyword(s):

Experimental Investigation ◽

Carbon Fiber ◽

Strain Measurement ◽

Cementitious Composite ◽

Fiber Reinforced ◽

Portal Frame ◽

Carbon Fiber Reinforced

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Evaluation of blank holder force effects on carbon fiber non-crimp fabric formability by a non-contact 3D strain measurement system

Composites - WIT Transactions on State of the Art in Science and Engineering ◽

10.2495/978-1-78466-167-0/007 ◽

2015 ◽

pp. 63-42

Author(s):

K. Tanaka

Keyword(s):

Carbon Fiber ◽

Measurement System ◽

Strain Measurement ◽

Blank Holder Force ◽

Blank Holder

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THE APPLICATION OF FINITE ELEMENTS METHOD, STRAIN MEASUREMENT AND ACOUSTIC EMISSION FOR DETERMINATION FRACTURE MECHANISM OF CARBON FIBER-REINFORCED PLASTIC SAMPLES DURING STRENGTH TESTS

Kontrol Diagnostika ◽

10.14489/td.2015.04.pp.029-036 ◽

2015 ◽

pp. 29-36 ◽

Cited By ~ 3

Author(s):

L.N. Stepanova ◽

N.A. Kovalenko ◽

V.V. Chernova ◽

E.S. Ognyanova ◽

E.A. Drobyaz ◽

...

Keyword(s):

Acoustic Emission ◽

Carbon Fiber ◽

Finite Elements ◽

Fracture Mechanism ◽

Strain Measurement ◽

Finite Elements Method ◽

Carbon Fiber Reinforced Plastic ◽

Fiber Reinforced Plastic ◽

Reinforced Plastic ◽

Strength Tests

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Fractographic relation between progressive failure and strain measurement techniques for recently developed configuration of carbon fiber/epoxy laminate

Polymer Testing ◽

10.1016/j.polymertesting.2016.10.036 ◽

2017 ◽

Vol 57 ◽

pp. 156-164 ◽

Cited By ~ 4

Author(s):

Jan Mayén ◽

Arturo Abúndez ◽

Enrique Alcudia ◽

José Antonio Arellano ◽

Jorge Colín ◽

...

Keyword(s):

Carbon Fiber ◽

Strain Measurement ◽

Progressive Failure ◽

Measurement Techniques ◽

Carbon Fiber Epoxy

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Strain Transfer Characteristic of a Fiber Bragg Grating Sensor Bonded to the Surface of Carbon Fiber Reinforced Polymer Laminates

Applied Sciences ◽

10.3390/app8071171 ◽

2018 ◽

Vol 8 (7) ◽

pp. 1171

Author(s):

Zhongyu Wang ◽

Hongyang Li ◽

Li Zhang ◽

Jingfeng Xue

Keyword(s):

Carbon Fiber ◽

Strain Measurement ◽

Fiber Reinforced Polymer ◽

Carbon Fiber Reinforced Polymer ◽

Transfer Model ◽

Strain Transfer ◽

Cfrp Laminates ◽

Reinforced Polymer ◽

Host Materials ◽

Fbg Sensors

Structural health monitoring is of great importance for the application of composites in aircrafts. Fiber Bragg grating (FBG) sensors are very suitable for structure strain measurement. However, the strain measured by FBG sensors is different from the original strain in host materials. The relationship between them is defined as strain transfer. As composites are anisotropic, the traditional strain transfer model, which regards the elasticity modulus of host materials as a constant, is inadaptable. In this paper, a new strain transfer model is proposed for FBG sensors bonded to the surface of carbon fiber reinforced polymer (CFRP) laminates. Based on the measurement structure, the model is established and the transfer function is derived. The characteristics influencing the strain transfer are analyzed. The stacking directions, stacking numbers, and stacking sequences of CFRP laminates have a distinct effect on the transfer efficiency, which is different from the isotropy host materials. The accuracy of the proposed model was verified by experiments on a nondestructive tensile system, and the maximum model error is less than 0.5%. Moreover, the model was applied to the strain measurement of CFRP wing skin, which indicates that measurement errors decrease by 11.6% to 19.8% after the compensation according to the model.

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Application of Digital Image Monitoring System in Strain Measurement of Cantilever Steel Beam

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.29-32.112 ◽

2010 ◽

Vol 29-32 ◽

pp. 112-117

Author(s):

Peng Hui Li ◽

Yin Ping Wen ◽

Wen Guang Zhao ◽

Hong Ping Zhu

Keyword(s):

Digital Image ◽

Strain Measurement ◽

Region Growing ◽

Calibration Method ◽

Processing Technique ◽

Image Processing Technique ◽

Steel Beam ◽

Image Monitoring ◽

Measurement Principle ◽

Cubic Polynomial

The realization of strain measurement based on digital image processing technique is discussed. Combined with the strain measurement principle and the optical imaging feature, considered the axisymmetrical and non-axisymmetrical distortion, the automatic surface-fitting calibration method based on region growing is adopted. Cubic polynomial is applied to establish the relationship between the object space and pixel coordinate system. The expectations based on wavelet coefficients are used for sub-pixel edge detection, measurement accuracy can reach 0.02 pixels. Accuracy of displacement for strain measurement achieves micrometer-level. The theoretic validity and practical feasibility of the system are proved by the strain measurement of a cantilever steel beam.

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