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.

scholarly journals Effect of Interface Properties on Tensile and Fatigue Behavior of 2D Woven SiC/SiC Fiber-Reinforced Ceramic-Matrix Composites

2020 ◽  
Vol 2020 ◽  
pp. 1-17
Author(s):  
Longbiao Li
Keyword(s):  
Fatigue Behavior ◽  
Ceramic Matrix Composites ◽  
Matrix Cracking ◽  
Interface Debonding ◽  
Interface Properties ◽  
Matrix Interface ◽  
Fiber Matrix Interface ◽  
Fiber Matrix ◽  
Stress Matrix ◽  
Cracking Stress

In this paper, the effect of the fiber/matrix interface properties on the tensile and fatigue behavior of 2D woven SiC/SiC ceramic-matrix composites (CMCs) is investigated. The relationships between the interface parameters of the fiber/matrix interface debonding energy and interface frictional shear stress in the interface debonding region and the composite tensile and fatigue damage parameters of first matrix cracking stress, matrix cracking density, and fatigue hysteresis-based damage parameters are established. The effects of the fiber/matrix interface properties on the first matrix cracking stress, matrix cracking evolution, first and complete interface debonding stress, fatigue hysteresis dissipated energy, hysteresis modulus, and hysteresis width are analyzed. The experimental first matrix cracking stress, matrix cracking evolution, and fatigue hysteresis loops of SiC/SiC composites are predicted using different interface properties.

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.

scholarly journals Effect of Cyclic Fatigue Loading on Matrix Multiple Fracture of Fiber-Reinforced Ceramic-Matrix Composites

Ceramics ◽  
2019 ◽  
Vol 2 (2) ◽  
pp. 327-346 ◽  
Author(s):  
Longbiao Li
Keyword(s):  
Ceramic Matrix Composites ◽  
Ceramic Matrix ◽  
Fatigue Loading ◽  
Cyclic Fatigue ◽  
Matrix Cracking ◽  
Matrix Composites ◽  
Matrix Interface ◽  
Multiple Fracture ◽  
Fiber Matrix Interface ◽  
Fiber Matrix

In this paper, the effect of cyclic fatigue loading on matrix multiple fracture of fiber-reinforced ceramic-matrix composites (CMCs) is investigated using the critical matrix strain energy (CMSE) criterion. The relationships between multiple matrix cracking, cyclic fatigue peak stress, fiber/matrix interface wear, and debonding are established. The effects of fiber volume fraction, fiber/matrix interface shear stress, and applied cycle number on matrix multiple fracture and fiber/matrix interface debonding and interface wear are discussed. Comparisons of multiple matrix cracking with/without cyclic fatigue loading are analyzed. The experimental matrix cracking of unidirectional SiC/CAS, SiC/SiC, SiC/Borosilicate, and mini-SiC/SiC composites with/without cyclic fatigue loading are predicted.

scholarly journals Finite Element Modeling of the Fiber-Matrix Interface in Polymer Composites

2020 ◽  
Vol 4 (2) ◽  
pp. 58 ◽  
Author(s):  
Daljeet K. Singh ◽  
Amol Vaidya ◽  
Vinoy Thomas ◽  
Merlin Theodore ◽  
Surbhi Kore ◽  
...  
Keyword(s):  
Finite Element ◽  
Stress Distribution ◽  
Polymer Composites ◽  
Parametric Study ◽  
Single Fiber ◽  
Interface Debonding ◽  
Matrix Interface ◽  
The Matrix ◽  
Fiber Matrix Interface ◽  
Fiber Matrix

Polymer composites are used in numerous industries due to their high specific strength and high specific stiffness. Composites have markedly different properties than both the reinforcement and the matrix. Of the several factors that govern the final properties of the composite, the interface is an important factor that influences the stress transfer between the fiber and matrix. The present study is an effort to characterize and model the fiber-matrix interface in polymer matrix composites. Finite element models were developed to study the interfacial behavior during pull-out of a single fiber in continuous fiber-reinforced polymer composites. A three-dimensional (3D) unit-cell cohesive damage model (CDM) for the fiber/matrix interface debonding was employed to investigate the effect of interface/sizing coverage on the fiber. Furthermore, a two-dimensional (2D) axisymmetric model was used to (a) analyze the sensitivity of interface stiffness, interface strength, friction coefficient, and fiber length via a parametric study; and (b) study the shear stress distribution across the fiber-interface-matrix zone. It was determined that the force required to debond a single fiber from the matrix is three times higher if there is adequate distribution of the sizing on the fiber. The parametric study indicated that cohesive strength was the most influential factor in debonding. Moreover, the stress distribution model showed the debonding mechanism of the interface. It was observed that the interface debonded first from the matrix and remained in contact with the fiber even when the fiber was completely pulled out.

A thermomechanical fatigue hysteresis-based damage evolution model for fiber-reinforced ceramic–matrix composites

2018 ◽  
Vol 28 (3) ◽  
pp. 380-403 ◽  
Author(s):  
Li Longbiao
Keyword(s):  
Damage Evolution ◽  
Ceramic Matrix Composites ◽  
Peak Stress ◽  
Fatigue Loading ◽  
Thermomechanical Fatigue ◽  
Interface Debonding ◽  
Matrix Interface ◽  
Cycle Number ◽  
Fiber Matrix Interface ◽  
Fiber Matrix

In this paper, a thermomechanical fatigue hysteresis-based damage evolution model for fiber-reinforced ceramic–matrix composites has been developed. Upon unloading and reloading, the fiber/matrix interface debonded length, interface counter-slip length, and interface new-slip length change with increasing or decreasing applied stress, which affects the stress–strain fatigue hysteresis loops and fatigue hysteresis-based damage parameters. The reloading/unloading stress–strain relationships when fiber/matrix interface partially or completely debonding are determined as a function of interface debonding/sliding, peak stress, applied cycle number, and thermal cycle temperature. The relationships between thermomechanical fatigue loading parameters (i.e. peak stress, applied cycle number, and thermal cyclic temperature), fiber/matrix interface debonding/sliding lengths, and fatigue hysteresis-based damage parameters (i.e. fatigue hysteresis dissipated energy, fatigue hysteresis modulus, and fatigue peak strain) have been established. The effects of fiber volume fraction, peak stress, matrix cracking space, and thermal cyclic temperature range on damage evolution under the out-of-phase thermomechanical cyclic loading have been discussed. The differences in damage evolution between in-phase/out-of-phase thermomechanical fatigue and isothermal fatigue loading at the same peak stress have been analyzed. The damage evolution of cross-ply SiC/magnesium aluminosilicate composite under the out-of-phase thermomechanical and isothermal fatigue loading has been predicted.

Thermomechanical Fatigue of Ceramic Matrix Composites

2019 ◽  
Author(s):  
Li Longbiao
Keyword(s):  
Slip Length ◽  
Hysteresis Loops ◽  
Ceramic Matrix Composites ◽  
Ceramic Matrix ◽  
Interface Debonding ◽  
Matrix Composites ◽  
Matrix Interface ◽  
Fiber Reinforced ◽  
Fiber Matrix Interface ◽  
Fiber Matrix

Abstract In this paper, the thermomechanical fatigue (TMF) of fiber-reinforced ceramic-matrix composites (CMCs) is investigated using the hysteresis-based damage parameter. The micro stress field of the damaged CMCs of matrix cracking and fiber/matrix interface debonding is obtained considering the temperature-dependent fiber/matrix interface shear stress. The fiber/matrix interface debonded length and unloading/reloading slip length are determined using the fracture mechanics approach. Based on the damage mechanisms of fiber sliding relative to the matrix in the interface debonded region, the TMF hysteresis loops models and hysteresis-based damage parameters are developed for the partially and completely debonding to analyze the damage evolution inside of fiber-reinforced CMCs. The effects of temperature, phase angle and loading sequences on the damage development of SiC/SiC composite are discussed. When TMF temperature range increases, the fatigue hysteresis loops area, residual strain increase, and the hysteresis modulus decreases, due to the increase of the fiber/matrix interface slip length. Under TMF loading, the phase angle affects the interface debonding and sliding range, and the hysteresis loops shape, location and area of the fiber-reinforced CMCs. The experimental TMF damage evolution of 2D SiC/SiC and cross-ply SiC/MAS composites are predicted.

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