Accelerated creep and creep-rupture testing of transverse unidirectional carbon/epoxy lamina based on the stepped isostress method

Tanks, Jonathon; Rader, Katherine E.; Sharp, Stephen R; Sakai, Takenobu

doi:10.1016/j.compstruct.2016.09.096

Cited by 36 publications

(21 citation statements)

References 23 publications

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“…., t n−2 to t n−1 , t n−1 to t n . is paper presents a quasielastic constitutive model of concrete considering creep and shrinkage based on age-adjusted e ective modulus method (Equations (8)- (10)). e model is in recursion form, which comforts codes programming and improves calculating e ciency.…”

Section: Modeling Of Time-dependent Materials Propertymentioning

confidence: 99%

“…In fact, under sustained load, concrete exhibits clear creep response, and the viscous property of adhesive is remarkable [4][5][6][7]. Related to the kind of fiber used and fiber content, some types of FRP products may also present noticeable viscoelasticity [8][9][10]. As time goes on, structure deformation increases and cracks further develop, which negatively affects the serviceability [11].…”

Section: Introductionmentioning

confidence: 99%

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Finite Element Modeling of FRP‐Strengthened RC Beam under Sustained Load

Jiang

Yao

Chen

et al. 2018

Advances in Materials Science and Engineering

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External bonding of FRP laminates to the tension soffit of concrete members has become a popular method for flexural strengthening. However, the long-term field performance of FRP-strengthened RC members under service conditions is still a concern, and more work needs to be done. Based on concrete smeared-crack approach, this paper presents a finite-element (FE) model for predicting long-term behavior of FRP-strengthened RC beam, which considers the time-dependent properties of all components including the aging effect of concrete. According to the comparison between theoretical predictions and test results, the validity of the FE model is verified. The interfacial edge stresses in adhesive layer were determined through appropriate mesh refinement near the plate end, and their time-dependent characteristics were investigated. The results show that creep of concrete and epoxy resin cause significant variations of the edge stresses with time. According to the research in this paper, the FE approach is found to be able to properly simulate the long-term behavior of the FRP-strengthened beam and help us better understand the complex changes in the stress state occurring over time.

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Section: Modeling Of Time-dependent Materials Propertymentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Finite Element Modeling of FRP‐Strengthened RC Beam under Sustained Load

Jiang

Yao

Chen

et al. 2018

Advances in Materials Science and Engineering

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“…Therefore, the evaluation of creep behavior is essential in engineering applications. At realistic service-life durations, conventional creep tests are time-consuming [19]. To reduce the duration of a creep test, an accelerated creep test is required to obtain a master curve that is based on the superposition principle, consisting of the duration time, exposure temperature, and applied stress.…”

Section: Introductionmentioning

confidence: 99%

Long-Term Creep Behavior Prediction of Sol-Gel Derived SiO2- and TiO2-Wood Composites Using the Stepped Isostress Method

Hung

Wu²,

2019

Polymers

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In this study, methyltrimethoxysilane (MTMOS), methyltriethoxysilane (MTEOS), tetraethoxysilane (TEOS), and titanium(IV) isopropoxide (TTIP) were used as precursor sols to prepare wood-inorganic composites (WICs) by a sol-gel process, and subsequently, the long-term creep behavior of these composites was estimated by application of the stepped isostress method (SSM). The results revealed that the flexural modulus of wood and WICs were in the range of 9.8–10.5 GPa, and there were no significant differences among them. However, the flexural strength of the WICs (93–103 MPa) was stronger than that of wood (86 MPa). Additionally, based on the SSM processes, smooth master curves were obtained from different SSM testing parameters, and they fit well with the experimental data. These results demonstrated that the SSM was a useful approach to evaluate the long-term creep behavior of wood and WICs. According to the Eyring equation, the activation volume of the WICs prepared from MTMOS (0.825 nm3) and TEOS (0.657 nm3) was less than that of the untreated wood (0.832 nm3). Furthermore, the WICs exhibited better performance on the creep resistance than that of wood, except for the WICMTEOS. The reduction of time-dependent modulus for the WIC prepared from MTMOS was 26% at 50 years, which is the least among all WICs tested. These findings clearly indicate that treatment with suitable metal alkoxides could improve the creep resistance of wood.

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“…However, very little attention has been paid to the creep behavior of WICs. At realistic service-life durations, time is too limited for conducting conventional creep tests, i.e., accelerated tests are necessary [23]. The concept of the accelerated creep test for the prediction of long-term performance is the use of the superposition principle from the combination of exposure time, exposure temperature, and applied load.…”

Section: Introductionmentioning

confidence: 99%

“…From this principle, the stepped isothermal method (SIM) has been developed to use stepped increments of temperature for a single sample [27,28,29,30]. Recently, the stepped isostress method (SSM), which can capture the creep behavior of a single sample with a stepwise increase in the stress level, was successfully applied to semi-crystalline thermoplastics and a carbon-fiber-reinforced polymer [23,31,32,33,34]. In comparison to SIM, additionally, the SSM is more advantageous in evaluating creep behavior of wood and WICs, because they are low-thermal-conductivity materials.…”

Section: Introductionmentioning

confidence: 99%

Effect of SiO2 Content on the Extended Creep Behavior of SiO2-Based Wood-Inorganic Composites Derived via the Sol–Gel Process Using the Stepped Isostress Method

Hung

2018

Polymers

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In this study, methyltrimethoxysilane (MTMOS) was used as a reagent to prepare SiO 2 -based wood-inorganic composites (WIC SiO 2 ) via the sol-gel process, and subsequently, the extended creep behaviors of WIC SiO 2 with weight percent gains (WPGs) of 10%, 20%, and 30% were estimated using the stepped isostress method (SSM). The results revealed that the density of all samples ranged from 426 to 513 kg/m 3 , and no significant difference in the modulus of elasticity (MOE) was noted among all of the samples (10.5–10.7 GPa). However, the MOR of WIC SiO 2 with a WPG of 20% (102 MPa) was significantly greater than that of untreated wood (87 MPa). In addition, according to the result using the SSM, the SSM-predicted creep master curve fitted well with the experimental data for the untreated wood and WIC SiO 2 . This result demonstrated that the SSM could be a useful method to evaluate long-term creep behaviors of wood and WIC SiO 2 . Furthermore, the activation volume ( V *) of the specimens was calculated from the linear slope of Eyring plots, and the resulting V * of all of the WIC SiO 2 (0.754–0.842 nm 3 ) was lower than that of untreated wood (0.856 nm 3 ). On the other hand, the modulus reduction of untreated wood showed 39%, 45%, 48%, and 51% at 5, 15, 30, and 50 years, respectively. In contrast, the modulus reduction of the WIC SiO 2 with a WPG of 10% decreased to 25%, 31%, 35%, and 38% at 5, 15, 30, and 50 years, respectively. Similar trends were also observed for other WIC SiO 2 with different WPGs. Of these, the WIC SiO 2 with a WPG of 20% exhibited the lowest reduction in time-dependent modulus (31%) over a 50-year period. Accordingly, the creep resistance of the wood could be effectively enhanced under the MTMOS treatment.

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Accelerated creep and creep-rupture testing of transverse unidirectional carbon/epoxy lamina based on the stepped isostress method

Cited by 36 publications

References 23 publications

Finite Element Modeling of FRP‐Strengthened RC Beam under Sustained Load

Finite Element Modeling of FRP‐Strengthened RC Beam under Sustained Load

Long-Term Creep Behavior Prediction of Sol-Gel Derived SiO2- and TiO2-Wood Composites Using the Stepped Isostress Method

Effect of SiO2 Content on the Extended Creep Behavior of SiO2-Based Wood-Inorganic Composites Derived via the Sol–Gel Process Using the Stepped Isostress Method

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