scholarly journals Variational formulation of generalized interfaces for finite deformation elasticity

2017 ◽  
Vol 23 (9) ◽  
pp. 1303-1322 ◽  
Author(s):  
Ali Javili
Keyword(s):  
Finite Deformation ◽  
Cohesive Zone Model ◽  
Finite Thickness ◽  
Heterogeneous Material ◽  
Zone Model ◽  
Interface Model ◽  
Consistent Model ◽  
Consistent Manner ◽  
Elastic Interface ◽  
General Interface

The objective of this contribution is to formulate generalized interfaces in a variationally consistent manner within a finite deformation continuum mechanics setting. The general interface model is a zero-thickness model that represents the finite thickness “interphase” between different constituents in a heterogeneous material. The interphase may be the transition zone between inclusion and matrix in composites or the grain boundaries in polycrystalline solids. The term “general” indicates that the interface model here accounts for both jumps of the deformation as well as the traction across the interface. Both the cohesive zone model and elastic interface model can be understood as two limits of the current interface model. Furthermore, some aspects of material modeling of generalized interfaces are elaborated and a consistent model is proposed. Finally, the proposed theory is elucidated via a series of numerical examples.

Investigation on Interfacial Bonding Strength of Anisotropic Conducive Adhesive with a New Cohesive Zone Model

2010 ◽  
Vol 654-656 ◽  
pp. 1928-1931
Author(s):  
Jun Zhang ◽  
Yong Cheng Lin ◽  
Xin Li Wei ◽  
Liu Gang Huang
Keyword(s):  
Bonding Strength ◽  
Cohesive Zone ◽  
Thermal Cycle ◽  
Cohesive Zone Model ◽  
Zone Model ◽  
Interface Model ◽  
Damage Factor ◽  
Adhesive Film ◽  
User Subroutine ◽  
Interfacial Bonding Strength

A modified cohesive zone interface model with a damage factor was proposed to describe the effects of the thermal cycle and humidity aging on the strengths of adhesive joints. The damage factor can not only change the cohesive zone bonding strength but also affect the energies of separation. The modified cohesive zone interfacial model, as a user subroutine, is developed and implemented in ABAQUS to simulate the 90° peeling process of the specimens, which were bonded by anisotropic conducive adhesive film (ACF) and subjected to the cycle and humidity aging tests. The numerical simulated results well agree with experimental results, which confirmed the validity of the new model.

Revisiting the Problem of Debond Initiation at Fibre-Matrix Interface under Transversal Biaxial Loads - A Comparison of Several Non-Classical Fracture Mechanics Approaches

2016 ◽  
Vol 713 ◽  
pp. 232-235 ◽  
Author(s):  
L. Távara ◽  
I.G. García ◽  
Roman Vodička ◽  
C.G. Panagiotopoulos ◽  
Vladislav Mantič
Keyword(s):  
Fracture Mechanics ◽  
Cohesive Zone Model ◽  
Failure Criteria ◽  
Transverse Load ◽  
Zone Model ◽  
Interface Model ◽  
Matrix Interface ◽  
Linear Elastic ◽  
Energetic Approach ◽  
Fibre Matrix

Understanding matrix failure in LFRP composites is one of the main challenges when developing failure criteria for these materials. This work aims to study the influence of the secondary transverse load on the crack initiation at micro-scale. Four non-classical approaches of fracture mechanics are used to model the onset of fibre-matrix interface debonds: Linear Elastic Brittle Interface Model (LEBIM), an Energetic Approach for the Linear Elastic Brittle Interface Model (EA-LEBIM), an Energetic Approach for the bilinear Cohesive Zone Model (EA-CZM) and the Coupled Criterion of the Finite Fracture Mechanics (CC-FFM). Results obtained by these approaches predict that, for brittle fibre-matrix configurations, a secondary transverse compression reduces the critical value of the main transverse tension leading to the debond onset. This fact is not taken into account by the currently used failure criteria

scholarly journals A note on traction continuity across an interface in a geometrically non-linear framework

2018 ◽  
Vol 24 (8) ◽  
pp. 2478-2496 ◽  
Author(s):  
Ali Javili
Keyword(s):  
Spatial Configuration ◽  
Three Dimensional ◽  
Interface Model ◽  
Cohesive Interface ◽  
Interface Models ◽  
Linear Framework ◽  
Non Linear ◽  
Spatial Configurations ◽  
Elastic Interface ◽  
General Interface

The objective of this contribution is to elaborate on the notion of “traction continuity” across an interface at finite deformations. The term interface corresponds to a zero-thickness model representing the interphase between different constituents in a material. Commonly accepted interface models are the cohesive interface model and the elastic interface model. Both the cohesive and elastic interface models are the limit cases of a generalized interface model. This contribution aims to rigorously analyze the concept of the traction jump for the general interface model. The governing equations of the general interface model in the material as well as spatial configurations are derived and the traction jump across the interface for each configuration is highlighted. It is clearly shown that the elastic interface model undergoes a traction jump in both the material and spatial configurations according to a generalized Young–Laplace equation. For the cohesive interface model, however, while the traction field remains continuous in the material configuration, it can suffer a jump in the spatial configuration. This finding is particularly important since the cohesive interface model is based on the assumption of traction continuity across the interface and that the term “traction” often refers to the spatial configuration and not the material one. Thus, additional care should be taken when formulating an interface model in a geometrically non-linear framework. The theoretical findings for various interface models are carefully illustrated via a series of two-dimensional and three-dimensional numerical examples using the finite element method.

Cracking Simulation of Asphalt Mixtures Using a Finite Element Micromechanical Model

2012 ◽  
Vol 598 ◽  
pp. 477-483
Author(s):  
Jing Hui Liu
Keyword(s):  
Finite Element ◽  
Cohesive Zone Model ◽  
Model Simulation ◽  
Micromechanical Model ◽  
Asphalt Mixture ◽  
Heterogeneous Material ◽  
Tensile Tests ◽  
Asphalt Mixtures ◽  
Zone Model ◽  
Material Heterogeneity

Cracking in the surface layer of asphalt pavement has been shown to be a major source of distress in roadways. Asphalt mixture is typically a heterogeneous material composed of aggregates, binder and air voids. Previous cracking studies have not considered the material heterogeneity. Digital Image Processing techniques is a powerful tool to describe the microstructure of the material. A micromechanical cohesive zone model that introduces ductility at the crack tip has been used to simulate the cracking of asphalt mixtures. ABAQUS software is a convenient finite element method to conduct simulations of particular laboratory specimens such as Indirect Tensile Tests(IDT) considering the micromechanical model. Simulation results of the IDT compared favorably with experimental results. Even though this study presented a attempt of a numerical simulation of a simple IDT test, the theory and methods adopted by the study can be applied to the fatigue damage study under the complicated loading considering the material heterogeneity, and then would effectively allow researchers link the micro-scale damage observed on the local scale with the real pavements fail on the global scale.

scholarly journals Experimental Testing and Analytical Modeling of Asymmetric End-Notched Flexure Tests on Glass-Fiber Metal Laminates

Metals ◽  
2019 ◽  
Vol 10 (1) ◽  
pp. 56 ◽  
Author(s):  
Konrad Dadej ◽  
Jarosław Bieniaś ◽  
Paolo Sebastiano Valvo
Keyword(s):  
Glass Fiber ◽  
Experimental Testing ◽  
Metal Composite ◽  
Interface Model ◽  
Experimental Campaign ◽  
Composite Interface ◽  
Theoretical Predictions ◽  
Elastic Interface ◽  
Fiber Metal ◽  
Rigid Interface

An experimental campaign on glass-fiber/aluminum laminated specimens was conducted to assess the interlaminar fracture toughness of the metal/composite interface. Asymmetric end-notched flexure tests were conducted on specimens with different fiber orientation angles. The tests were also modeled by using two different analytical solutions: a rigid interface model and an elastic interface model. Experimental results and theoretical predictions for the specimen compliance and energy release rate are compared and discussed.

scholarly journals Ultrasonic Deicing Efficiency Prediction and Validation for a Flat Deicing System

2020 ◽  
Vol 10 (19) ◽  
pp. 6640
Author(s):  
Zhonghua Shi ◽  
Zhenhang Kang ◽  
Qiang Xie ◽  
Yuan Tian ◽  
Yueqing Zhao ◽  
...  
Keyword(s):  
Lead Zirconate Titanate ◽  
Cohesive Zone ◽  
Cohesive Zone Model ◽  
Lead Zirconate ◽  
Efficiency Factor ◽  
Zone Model ◽  
Shear Stresses ◽  
Stress Distributions ◽  
Total Energy Density ◽  
Average Shear

An effective deicing system is needed to be designed to conveniently remove ice from the surfaces of structures. In this paper, an ultrasonic deicing system for different configurations was estimated and verified based on finite element simulations. The research focused on deicing efficiency factor (DEF) discussions, prediction, and validations. Firstly, seven different configurations of Lead zirconate titanate (PZT) disk actuators with the same volume but different radius and thickness were adopted to conduct harmonic analysis. The effects of PZT shape on shear stresses and optimal frequencies were obtained. Simultaneously, the average shear stresses at the ice/substrate interface and total energy density needed for deicing were calculated. Then, a coefficient named deicing efficiency factor (DEF) was proposed to estimate deicing efficiency. Based on these results, the optimized configuration and deicing frequency are given. Furthermore, four different icing cases for the optimize configuration were studied to further verify the rationality of DEF. The effects of shear stress distributions on deicing efficiency were also analyzed. At same time, a cohesive zone model (CZM) was introduced to describe interface behavior of the plate and ice layer. Standard-explicit co-simulation was utilized to model the wave propagation and ice layer delamination process. Finally, the deicing experiments were carried out to validate the feasibility and correctness of the deicing system.

scholarly journals An Improved Cohesive Zone Model for Interface Mixed-Mode Fractures of Railway Slab Tracks

2021 ◽  
Vol 11 (1) ◽  
pp. 456
Author(s):  
Yanglong Zhong ◽  
Liang Gao ◽  
Xiaopei Cai ◽  
Bolun An ◽  
Zhihan Zhang ◽  
...  
Keyword(s):  
Interface Crack ◽  
Cohesive Zone ◽  
Mixed Mode ◽  
Cohesive Zone Model ◽  
Complex Loading ◽  
Bending Test ◽  
Mixed Mode Fracture ◽  
Zone Model ◽  
Slab Track ◽  
Interfacial Cracks

The interface crack of a slab track is a fracture of mixed-mode that experiences a complex loading–unloading–reloading process. A reasonable simulation of the interaction between the layers of slab tracks is the key to studying the interface crack. However, the existing models of interface disease of slab track have problems, such as the stress oscillation of the crack tip and self-repairing, which do not simulate the mixed mode of interface cracks accurately. Aiming at these shortcomings, we propose an improved cohesive zone model combined with an unloading/reloading relationship based on the original Park–Paulino–Roesler (PPR) model in this paper. It is shown that the improved model guaranteed the consistency of the cohesive constitutive model and described the mixed-mode fracture better. This conclusion is based on the assessment of work-of-separation and the simulation of the mixed-mode bending test. Through the test of loading, unloading, and reloading, we observed that the improved unloading/reloading relationship effectively eliminated the issue of self-repairing and preserved all essential features. The proposed model provides a tool for the study of interface cracking mechanism of ballastless tracks and theoretical guidance for the monitoring, maintenance, and repair of layer defects, such as interfacial cracks and slab arches.

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