scholarly journals Bonding Behaviors of GFRP/Steel Bonded Joints after Wet–Dry Cyclic and Hygrothermal Curing

2020 ◽  
Vol 10 (16) ◽  
pp. 5411
Author(s):  
Jie Liu ◽  
Tong Guo ◽  
Matthew H. Hebdon ◽  
Zhongxiang Liu ◽  
Libin Wang
Keyword(s):  
Fracture Energy ◽  
Failure Modes ◽  
Experimental Studies ◽  
Interfacial Fracture ◽  
Threshold Value ◽  
Mechanism Analysis ◽  
Cohesive Failure ◽  
Curing Conditions ◽  
Bonding Performance ◽  
Interfacial Fracture Energy

This paper presents the outcomes of a research program that tested and examined the behaviors of glass fiber-reinforced polymer (GFRP) bonded steel double-strap joints after being cured in a variety of harsh curing conditions. Nineteen specimens were manufactured, cured in an air environment (the reference specimen), treated with different wet–dry cyclic curing or hygrothermal pretreatment, and then tested under quasi-static loading. Based on the experimental studies, mixed failure modes, rather than the cohesive failure of the adhesive, were found in the harsh environmental cured specimens. Additionally, an approximately linear relationship of load–displacement curves was observed for all the GFRP/steel bonded specimens from which the tensile capacities and stiffness were discussed. By analyzing the strain development of the bonded specimens during quasi-static tensile testing, the fracture mechanism analysis focused on the threshold value of the strain curves for different cured specimens. Finally, based on the studies of interfacial fracture energy, Gf, the effects of harsh environmental curing were assessed. The results showed that the failure modes, joint tensile capacities, stiffness, and interfacial fracture energy Gf were highly dependent on the curing conditions, and a significant degradation of bonding performance could be introduced by the investigated harsh environments.

scholarly journals Durability of the Bond between CFRP and Concrete Exposed to Thermal Cycles

Materials ◽  
2019 ◽  
Vol 12 (3) ◽  
pp. 515 ◽  
Author(s):  
Shuai Liu ◽  
Yunfeng Pan ◽  
Hedong Li ◽  
Guijun Xian
Keyword(s):  
Fracture Energy ◽  
Failure Modes ◽  
Interfacial Fracture ◽  
Reduction Factor ◽  
Cohesive Failure ◽  
Thermal Cycles ◽  
Lap Shear ◽  
Cfrp Plate ◽  
Cfrp Sheet ◽  
Interfacial Fracture Energy

The bond between carbon fiber reinforced polymer (CFRP) and concrete is significantly and adversely affected by thermal cycles in air and water. In the present study, the effects of thermal cycles in air or water on the bond performance between CFRP and concrete were examined. A single-lap shear test was adopted to evaluate the performance of the CFRP−concrete bond. A number of 270 thermal cycles in air increased the interfacial fracture energy of the CFRP plate− and CFRP sheet−concrete by 35% and 20%, respectively while 270 thermal cycles in water reduced the interfacial fracture energy of the CFRP plate– and CFRP sheet−concrete by 9% and 46%, respectively. Thermal cycles in water caused the failure mode to change from concrete cohesive failure to primer−concrete interfacial debonding. The failure modes of CFRP−concrete exposed to thermal cycles in air still occurred in concrete. A reduction factor for the CFRP−concrete structure for thermal cycles in water was proposed.

Estimation of the Interfacial Fracture Energy of Metal/Polymer System in Microelectronic Packaging

2001 ◽  
Vol 682 ◽  
Author(s):  
J.Y. Song ◽  
Jin Yu
Keyword(s):  
Fracture Energy ◽  
Power Density ◽  
Polymer System ◽  
Peel Test ◽  
Interfacial Fracture ◽  
Peel Strength ◽  
Rf Plasma ◽  
Plasma Power ◽  
Interfacial Fracture Energy ◽  
Elastoplastic Beam

ABSTRACTThe interfacial fracture energies of flexible Cu/Cr/Polyimide system were deduced from the T peel test. The T peel strength and peel angle were strongly affected by the metal thickness and the biased rf plasma power density of the polyimide pretreatment. The plastic bending works of metal and polyimide dissipated during peel test were estimated from the direct measurement of maximum root curvatures using the elastoplastic beam analysis. The interfacial fracture energy between Cr and polyimide increased with the rf plasma power density and saturated, but was pretty much independent of the metal film thickness and the peel angle.

Analytical Studies on Mixed-Mode Debonding along the FRP–Concrete Interface in the Peeling Test

2011 ◽  
Vol 268-270 ◽  
pp. 247-251 ◽  
Author(s):  
Hong Chang Qu ◽  
Sheng Li Zhang ◽  
Ling Ling Chen
Keyword(s):  
Fracture Energy ◽  
Interfacial Fracture ◽  
Opening Displacement ◽  
Flexural Strengthening ◽  
Linear Elastic ◽  
Peeling Test ◽  
Interfacial Fracture Energy ◽  
Set Up ◽  
Concrete Interface ◽  
Frp Sheet

The bonding of fiber reinforced polymer (FRP) strips and plates to the concrete structures has been found to be an effective technique for flexural strengthening. The FRP is then under both pulling and peeling forces, resulting in a combination of shear sliding and opening displacement along the FRP/concrete interface. A novel experimental set-up is studied that a peeling load is applied on the FRP sheet by a circular rod placed into the central notch of the beam. Based on the linear-elastic fracture mechanics approach, a theoretical analysis is conducted on specimens representing the peeling behavior. From the numerical analysis, the load–displacement curves, load–stiffness of FRP sheet curves, and load–fracture energy curves affected by different variables are discussed. The peel load is related to the FRP sheet stiffness and to the interfacial fracture energy. Therefore, only two material parameters, the interfacial fracture energy of FRP–concrete interface and stiffness of FRP sheets, are necessary to represent the interfacial fracture behavior. The theoretical load–deflection curves of specimens agree well with the corresponding experimental results in the literatures.

scholarly journals Prediction of Load Capacity Variation in FRP Bonded Concrete Specimens Using Brownian Motion

2015 ◽  
Vol 2015 ◽  
pp. 1-9 ◽  
Author(s):  
Tayyebeh Mohammadi ◽  
Baolin Wan ◽  
Jian-Guo Dai ◽  
Chao Zhu
Keyword(s):  
Brownian Motion ◽  
Fracture Energy ◽  
Load Capacity ◽  
Concrete Strength ◽  
Experimental Tests ◽  
Interfacial Fracture ◽  
Concrete Surface ◽  
Concrete Members ◽  
Interfacial Fracture Energy ◽  
Mode Ii Loading

In wet lay-up process, dry fiber sheets are saturated with a polymer and applied to the concrete surface by hand. This causes relatively large variation in properties of the cured FRP composite material. It is hard to know the exact mechanical properties of the FRP constructed by wet lay-up process. In addition, the stiffness of FRP changes during debonding process due to different amount of concrete attached to the debonded FRP at different locations. It is also inevitable to have considerable variations in the strength of concrete. Therefore, the behaviour of FRP bonded concrete members varies among specimens even when the same materials are used. The variation of localized FRP stiffness and concrete strength can be combined in a single parameter as variation of the localized interfacial fracture energy. In an effort to effectively model the effects of the variation of interfacial fracture energy on the load versus deflection responses of FRP bonded concrete specimens subjected to Mode I and Mode II loading, a random white noise using a one-dimensional standard Brownian motion is added to the governing equations, yielding stochastic differential equations. By solving these stochastic equations, the bounds of load carrying capacity variation with 95% probability are found for different experimental tests.

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