Abstract
Numerical analysis software based on linear finnite element method and statistical damage theory concrete material has been adopted in this study. Dynamic numerical model of twin fibers pullout test of concrete matrix have been created by considering the meso-heterogeneity of concrete material. The whole process from micro-cracks initiation, propagation to crack penetration has been simulated. The influence of stress wave loading peak and loading rate on twin fibers pull-out test of concrete matrix under dynamic load has, therefore, been scrutinized. Results show that loading rate has effect on failure mode and crack propagation along interface of the twin fibers pull-out specimens. With increasing loading rates, the rate of interface crack propagation and damage area increase either.
Highlights
Fiber reinforced concrete is widely used in civil and structural engineering
There is a significant difference between the mechanical properties of concrete materials under dynamic load and quasi-static action[4]
Some scholars[5-8] consider the drawing performance experiments of deformed steel fibers with loading rate.in addition, because the bond mechanism between steel fiber and concrete is equivalent to that between steel bar and concrete[9], some scholars have analyzed the mechanism of steel fiber and concrete by studying the bond properties of steel bar and concrete at different loading rates [1011].Aiming at the complexity of the double-wire dynamic pull-out problem, this study, considering the influence of the fiber interface properties, establishes the dynamic numerical model of the double-wire pull-out of concrete by using RFPA2D-Dynamic(Realistic Failure Process
Summary
Fiber reinforced concrete is widely used in civil and structural engineering. Due to the physical and chemical interactions between the fibers and the matrix, a nanoscale thin layer is formed during the processing of the composites, which is called the interface [1].The interface between fiber and matrix in fiber reinforced concrete is an important microstructure. In order to explore the influence of the peak load and the change of the load rate on the performance of the twin fibers pullout of concrete matrix , a triangular dynamic stress wave as shown in Fig 2 was applied to the steel fiber in the model, with a total loading time of 20 μs. The macroscopic transverse main crack of the matrix between the fiber and fiber is pulled out and destroyed.When the loading peak and the loading rate are higher (Peak 6, Rate 1), the energy released during the failure of the specimen unit is higher, the interface crack propagation speed is accelerated, the interface debonding area and the damage amount of the base unit are significantly increased, and the interface is completely debonded ,the twin fiber is pulled out
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