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Biaxial yield surface investigation of polymer-matrix composites.

Ye J, Qiu Y, Zhai Z, He Z - Sensors (Basel) (2013)

Bottom Line: This article presents a numerical technique for computing the biaxial yield surface of polymer-matrix composites with a given microstructure.On this basis, the manufacturing process thermal residual stress and strain rate effect on the biaxial yield surface of composites are considered.The results show that the effect of thermal residual stress on the biaxial yield response is closely dependent on loading conditions.

View Article: PubMed Central - PubMed

Affiliation: Key Laboratory of Ministry of Education for Electronic Equipment Structure Design, Xidian University, Xi'an 710071, China. ronkey6000@sina.com

ABSTRACT
This article presents a numerical technique for computing the biaxial yield surface of polymer-matrix composites with a given microstructure. Generalized Method of Cells in combination with an Improved Bodner-Partom Viscoplastic model is used to compute the inelastic deformation. The validation of presented model is proved by a fiber Bragg gratings (FBGs) strain test system through uniaxial testing under two different strain rate conditions. On this basis, the manufacturing process thermal residual stress and strain rate effect on the biaxial yield surface of composites are considered. The results show that the effect of thermal residual stress on the biaxial yield response is closely dependent on loading conditions. Moreover, biaxial yield strength tends to increase with the increasing strain rate.

No MeSH data available.


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The structure of FBGs sensor.
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f3-sensors-13-04051: The structure of FBGs sensor.

Mentions: Due to their small dimensions and accurate measurements, as well as resistance to corrosion and electromagnetism, FBGs sensors have been used in cardiac ablation [13], structural health monitoring [14,15], as well as the biomechanics and rehabilitation fields [16]. The structure of a FBGs sensor can be seen in Figure 3. It is composed of an optical fiber, grating and fiber core. The fabrication process of FBGs sensor is due to the photosensitivity property of the doped silica glass fiber core. A permanent grating can be inscribed into the photosensitive fiber core when exposed to ultraviolet light and is usually obtained by means of the two-beam interference technique or phase mask method. The principle of the FBGs sensor is to measure the changes of center wavelengths of reflective light from a Bragg grating. With the variation of strain, the center wavelengths of the reflection light will be corresponding changed. The Bragg wavelength can be expressed as follows [17]:(8)λβ=2neffΛwhere neff is the effective reflective index of the fiber core, Λ is the grating periodic spacing, λβ is the wavelength of reflected light. It can be found from Equation (8) that the Bragg wavelength will shift with the parameter of neff and Λ. Disregarding the thermal influence, the periodic spacing and effective reflective index will change when the mechanical deformation is posed on the grating area. The relationship between Bragg wavelength shift and the change of strain (Δε) can be expressed as:(9)ΔλB=αΔɛwhere:(10)α=λB(1−pe)and pe is an effective strain-optic constant.


Biaxial yield surface investigation of polymer-matrix composites.

Ye J, Qiu Y, Zhai Z, He Z - Sensors (Basel) (2013)

The structure of FBGs sensor.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3673070&req=5

f3-sensors-13-04051: The structure of FBGs sensor.
Mentions: Due to their small dimensions and accurate measurements, as well as resistance to corrosion and electromagnetism, FBGs sensors have been used in cardiac ablation [13], structural health monitoring [14,15], as well as the biomechanics and rehabilitation fields [16]. The structure of a FBGs sensor can be seen in Figure 3. It is composed of an optical fiber, grating and fiber core. The fabrication process of FBGs sensor is due to the photosensitivity property of the doped silica glass fiber core. A permanent grating can be inscribed into the photosensitive fiber core when exposed to ultraviolet light and is usually obtained by means of the two-beam interference technique or phase mask method. The principle of the FBGs sensor is to measure the changes of center wavelengths of reflective light from a Bragg grating. With the variation of strain, the center wavelengths of the reflection light will be corresponding changed. The Bragg wavelength can be expressed as follows [17]:(8)λβ=2neffΛwhere neff is the effective reflective index of the fiber core, Λ is the grating periodic spacing, λβ is the wavelength of reflected light. It can be found from Equation (8) that the Bragg wavelength will shift with the parameter of neff and Λ. Disregarding the thermal influence, the periodic spacing and effective reflective index will change when the mechanical deformation is posed on the grating area. The relationship between Bragg wavelength shift and the change of strain (Δε) can be expressed as:(9)ΔλB=αΔɛwhere:(10)α=λB(1−pe)and pe is an effective strain-optic constant.

Bottom Line: This article presents a numerical technique for computing the biaxial yield surface of polymer-matrix composites with a given microstructure.On this basis, the manufacturing process thermal residual stress and strain rate effect on the biaxial yield surface of composites are considered.The results show that the effect of thermal residual stress on the biaxial yield response is closely dependent on loading conditions.

View Article: PubMed Central - PubMed

Affiliation: Key Laboratory of Ministry of Education for Electronic Equipment Structure Design, Xidian University, Xi'an 710071, China. ronkey6000@sina.com

ABSTRACT
This article presents a numerical technique for computing the biaxial yield surface of polymer-matrix composites with a given microstructure. Generalized Method of Cells in combination with an Improved Bodner-Partom Viscoplastic model is used to compute the inelastic deformation. The validation of presented model is proved by a fiber Bragg gratings (FBGs) strain test system through uniaxial testing under two different strain rate conditions. On this basis, the manufacturing process thermal residual stress and strain rate effect on the biaxial yield surface of composites are considered. The results show that the effect of thermal residual stress on the biaxial yield response is closely dependent on loading conditions. Moreover, biaxial yield strength tends to increase with the increasing strain rate.

No MeSH data available.


Related in: MedlinePlus