scholarly journals The Bond-Slip Relationship at FRP-to-Brick Interfaces under Dynamic Loading

Materials ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 545
Author(s):  
Di Zhang ◽  
Jun Yang ◽  
Li Yuan Chi

Interface debonding between fiber reinforced polymers (FPR) and substrates is the principal failure mode for FRP-reinforced structure. To understand the bond–slip relationship at FRP-to-brick interfaces under dynamic loading, the influences of the dynamic enhancement of material performance on the bond–slip curve were studied. Single-lap shear tests under two different loading rates were performed, and the slip distribution curves at different loading stages were fitted to derive the bond–slip relationship. Then a numerical model considering the strain rate effects on materials was built and verified with test results. Further, the influences of brick strength, FRP stiffness and slip rate on the bond–slip relationship were investigated numerically. The research results show that FRP stiffness mainly influences the shape of the bond–slip curve, while brick strength mainly influences the amplitude of the bond–slip curve. The variations of the bond–slip relationship under dynamic loading, i.e., under different slip rates, are mainly caused by the dynamic enhancement of brick strength, and also by the dynamic enhancement of FRP stiffness, especially within a specific slip rate range. The proposed empirical formula considering dynamic FRP stiffness and dynamic brick strength can be used to predict the bond–slip relationship at the FRP-to-brick interface under dynamic loading.

2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
H. A. Khawaja ◽  
T. A. Bertelsen ◽  
R. Andreassen ◽  
M. Moatamedi

The paper gives the study of the response of carbon fiber reinforced polymers (CRFP) quasi-isotropic shell structures under the influence of dynamic loading. The quasi-isotropic CRFP shell specimens are fabricated using Multipreg E720 laminates. These laminates are laid in such a way that shell structure has equal strength and mechanical properties in the two-dimensional (2D) plane and hence can be regarded as quasi-isotropic. In this study, the dynamic loading is generated using shock waves in a shock tube experimental setup. The strain and pressure data is collected from the experiments. Additional tests are carried out using Material Test System (MTS) for both tensile and flexural response of CRFP. Results obtained from experiments are compared with numerical simulations using ANSYS Multiphysics 14.0 finite element method (FEM) package. The numerical simulation and experimental results are found to be in good agreement.


2017 ◽  
Vol 2017 ◽  
pp. 1-14 ◽  
Author(s):  
Justin Shrestha ◽  
Dawei Zhang ◽  
Tamon Ueda

Environmental related durability issues have been of great concerns in the structures strengthened with the fiber reinforced polymers (FRPs). In marine environment, moisture is one of the dominant factors that adversely affect the material properties and the bond interfaces. Several short-term and long-term laboratory experimental investigations have been conducted to study such behaviors but, still, there are insufficient constitutive bond models which could incorporate moisture exposure conditions. This paper proposed a very simple approach in determining the nonlinear bond-slip models for the FRP-concrete interface considering the effect of moisture conditions. The proposed models are based on the strain results of the experimental investigation conducted by the authors using 6 different commercial FRP systems exposed to the moisture conditions for the maximum period of 18 months. The exposure effect in the moisture conditions seems to have great dependency on the FRP system. Based on the contrasting differences in the results under moisture conditions, separate bond-slip models have been proposed for the wet-layup FRP and prefabricated FRP systems. As for the verification of the proposed model under moisture conditions, predicted pull-out load was compared with the experimental pull-out load. The results showed good agreement for all the FRP systems under investigation.


Coatings ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 538
Author(s):  
Malal Kane ◽  
Ebrahim Riahi ◽  
Minh-Tan Do

This paper deals with the modeling of rolling resistance and the analysis of the effect of pavement texture. The Rolling Resistance Model (RRM) is a simplification of the no-slip rate of the Dynamic Friction Model (DFM) based on modeling tire/road contact and is intended to predict the tire/pavement friction at all slip rates. The experimental validation of this approach was performed using a machine simulating tires rolling on road surfaces. The tested pavement surfaces have a wide range of textures from smooth to macro-micro-rough, thus covering all the surfaces likely to be encountered on the roads. A comparison between the experimental rolling resistances and those predicted by the model shows a good correlation, with an R2 exceeding 0.8. A good correlation between the MPD (mean profile depth) of the surfaces and the rolling resistance is also shown. It is also noticed that a random distribution and pointed shape of the summits may also be an inconvenience concerning rolling resistance, thus leading to the conclusion that beyond the macrotexture, the positivity of the texture should also be taken into account. A possible simplification of the model by neglecting the damping part in the constitutive model of the rubber is also noted.


PAMM ◽  
2021 ◽  
Vol 20 (1) ◽  
Author(s):  
Nicola Magino ◽  
Jonathan Köbler ◽  
Heiko Andrä ◽  
Matti Schneider ◽  
Fabian Welschinger

Coatings ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 190
Author(s):  
Florian Cougnon ◽  
Mathias Kersemans ◽  
Wim Van Paepegem ◽  
Diederik Depla

Due to the low heat flux towards the substrate, magnetron sputter deposition offers the possibility to deposit thin films on heat sensitive materials such as fiber-reinforced polymers, also known as composite materials. Passive thermal probe measurements during the sputter deposition of metal layers show indeed that the temperature increase remains well below 25 °C for film thicknesses up to 600 nm. The latter thickness threshold is based on the influence of embedded metal films on the adhesion of the composite plies. Films thicker than this threshold deteriorate the mechanical integrity of the composite. The introduction of the uncured composite in the vacuum chamber strongly affects the base pressure by outgassing of impurities from the composite. The impurities affect the film properties as illustrated by their impact on the Seebeck coefficient of sputter deposited thermocouples. The restrictions to embed thin films in composites, as illustrated by both the heat flux measurements, and the study on the influence of impurities, are however not insurmountable. The possibility to use embedded thin films will be briefly demonstrated in different applications such as digital volume image correlation, thermocouples, and de-icing.


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