Fiber pullout model for aligned hooked-end steel fiber

2010 ◽  
Vol 37 (9) ◽  
pp. 1179-1188 ◽  
Author(s):  
P. Ghoddousi ◽  
R. Ahmadi ◽  
M. Sharifi
Keyword(s):  
Shear Stress ◽  
Analytical Model ◽  
Fiber Length ◽  
Steel Fiber ◽  
Matrix Interface ◽  
Force Component ◽  
Interfacial Bond ◽  
Fiber Pullout ◽  
Proposed Model ◽  
Fiber Matrix Interface

The main objective of this study is to derive an analytical model for the pullout behavior of hooked-end steel fiber. The pullout behavior of hooked-end steel fiber comprises a component due to interfacial bond stress at the fiber–matrix interface and a component due to mechanical anchorage at the hook end of the fiber. To study the first component, the effects of hooks on the distributions of the force and stresses along the fiber length are analyzed. Then these results are used, with the concept of bond shear stress versus slip relation between fiber and matrix, to obtain a force component due to the interfacial bond. After that the required theoretical relations are obtained to determine the component due to the mechanical anchorages. Finally, the model is validated with two existing experimental results on the hooked-end steel fiber pullout. The results show that the proposed model is able to estimate the pullout behavior of hooked-end steel fiber.

Experimental Investigation of the Interface between Synthetic and Glass Fibers and Lime-Based Mortars

2016 ◽  
Vol 825 ◽  
pp. 57-62
Author(s):  
Michal Přinosil
Keyword(s):  
Experimental Investigation ◽  
Analytical Model ◽  
Glass Fibers ◽  
Fiber Reinforcement ◽  
Pullout Test ◽  
Theoretical Curve ◽  
Matrix Interface ◽  
The Matrix ◽  
Fiber Matrix Interface ◽  
Displacement Diagram

In this article, the cohesion between fiber reinforcement and lime-based mortar is experimentally investigated using so-called pullout test. The experiment is based on the progressive pulling out of the fiber from the matrix. Comparing the experimental load-displacement diagram with the theoretical curve from the analytical model, the micromechanical parameters describing the fiber-matrix interface are evaluated. In the study, several types of synthetic and glass fibers are considered as well as two types of lime-based mortars. The first one is pure lime, while the second one has lime-metakaolin matrix.

A time-dependent tensile constitutive model for long-fiber-reinforced unidirectional ceramic-matrix minicomposites considering interface and fiber oxidation

2020 ◽  
Vol 29 (7) ◽  
pp. 1138-1166 ◽  
Author(s):  
Li Longbiao
Keyword(s):  
Shear Stress ◽  
Tensile Stress ◽  
Weibull Modulus ◽  
Oxidation Time ◽  
Matrix Cracking ◽  
Time Dependent ◽  
Interface Debonding ◽  
Matrix Interface ◽  
Fiber Failure ◽  
Fiber Matrix Interface

In this paper, a time-dependent tensile constitutive model of long-fiber-reinforced unidirectional ceramic-matrix minicomposites is developed considering the interface and fiber oxidation. The relationship between the time-dependent tensile behavior and internal damage is established. The damage mechanisms of time-dependent matrix cracking, fiber/matrix interface debonding, fiber failure, and the oxidation of the interface and fiber are considered in the analysis of the time-dependent tensile stress–strain curve. The fracture mechanic approach, matrix statistical cracking model, and fiber statistical failure model are used to determine the time-dependent interface debonding length, matrix crack spacing, and the fiber failure probability considering the time-dependent interface and fiber oxidation. The effects of the fiber volume, fiber radius, matrix Weibull modulus, matrix cracking characteristic strength, matrix cracking saturation spacing, interface shear stress, interface debonding energy, fiber strength, fiber Weibull modulus, and oxidation time on the time-dependent tensile stress–strain curves, matrix cracking density, interface debonding, and fiber failure are discussed. The experimental time-dependent tensile stress–strain curves, matrix cracking, interface debonding, and fiber failure of four different unidirectional SiC/SiC minicomposites for different oxidation time are predicted. The composite tensile strength and failure strain increase with the fiber volume, fiber strength, and fiber Weibull modulus, and decrease with the oxidation time; the fiber/matrix interface debonding length increases with the fiber radius and oxidation time and decreases with the interfacial shear stress and interface debonding energy; the fiber/matrix interface oxidation ratio increases with the interfacial shear stress, interface debonding energy, and oxidation time and decreases with the saturation matrix crack spacing.

Interfaces Studied by Electromechanical Pull-Out Testing

1996 ◽  
Vol 458 ◽  
Author(s):  
Xuli Fu ◽  
D. D. L. Chung
Keyword(s):  
Electrical Resistivity ◽  
Bond Strength ◽  
Shear Bond Strength ◽  
Steel Fiber ◽  
Contact Resistivity ◽  
Matrix Interface ◽  
Preparation Conditions ◽  
Pull Out ◽  
Fiber Matrix Interface

ABSTRACTThe experimental technique of electromechanical pull-out testing is introduced to study the interface between fiber and matrix. The technique involves measuring both the contact electrical resistivity and the shear bond strength of a fiber-matrix interface. Samples that are identically prepared differ in contact resistivity and bond strength, which correlate. The correlation allows determination of even small differences in bond strength due to differences in sample preparation conditions. It also gives information on the structure of the interface and allows the bond strength to be nondestructively determined by measuring the contact resistivity. The technique is demonstrated for the interface between steel fiber and cement.

scholarly journals Analytical Model for Estimating the Impact of Changing the Nominal Power Parameter in LTE

2018 ◽  
Vol 2018 ◽  
pp. 1-7
Author(s):  
A. B. Vallejo-Mora ◽  
M. Toril ◽  
S. Luna-Ramírez ◽  
M. Regueira ◽  
S. Pedraza
Keyword(s):  
Analytical Model ◽  
Mobile Networks ◽  
Radio Resource Management ◽  
Estimation Accuracy ◽  
Model Assessment ◽  
Power Parameter ◽  
Management Procedure ◽  
Proposed Model ◽  
A Cell ◽  
The Impact

UpLink Power Control (ULPC) is a key radio resource management procedure in mobile networks. In this paper, an analytical model for estimating the impact of increasing the nominal power parameter in the ULPC algorithm for the Physical Uplink Shared CHannel (PUSCH) in Long Term Evolution (LTE) is presented. The aim of the model is to predict the effect of changing the nominal power parameter in a cell on the interference and Signal-to-Interference-plus-Noise Ratio (SINR) of that cell and its neighbors from network statistics. Model assessment is carried out by means of a field trial where the nominal power parameter is increased in some cells of a live LTE network. Results show that the proposed model achieves reasonable estimation accuracy, provided uplink traffic does not change significantly.

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