An electromechanical cohesive zone model merging with contact and friction effects for fiber debonding and pushing-out in piezoelectric fiber composites

2021 ◽  
Vol 95 ◽  
pp. 1-21 ◽  
Author(s):  
Cihang Xie ◽  
Ying Wu ◽  
Zishun Liu
Keyword(s):  
Cohesive Zone ◽  
Cohesive Zone Model ◽  
Fiber Composites ◽  
Zone Model ◽  
Model Merging ◽  
Piezoelectric Fiber

scholarly journals MODELLING OF CRACK DEVELOPMENT PROCESSES IN COMPOSITE ELEMENTS BASED ON VIRTUAL CRACK CLOSURE TECHNIQUE AND COHESIVE ZONE MODEL

2020 ◽  
Vol 17 (35) ◽  
pp. 591-599
Author(s):  
Yulong; ; LI ◽  
Vasiliy N. DOBRYANSKIY ◽  
Alexander A. OREKHOV
Keyword(s):  
Composite Materials ◽  
Polymer Composite ◽  
Cohesive Zone ◽  
Cohesive Zone Model ◽  
Fiber Composites ◽  
Polymer Composite Materials ◽  
Zone Model ◽  
Virtual Crack Closure Technique ◽  
Closure Technique

Fiber composites based on polymer matrices are promising structural materials that meet high requirements for strength, reliability, durability, and hardness. Therefore, composite materials are widely used as structural materials for aerospace products. The problems associated with the destruction of fiber composites were relevant at all stages of technology development. A variety of reinforcing fibers and polymer binders, as well as reinforcement schemes, allow directional control of strength, stiffness, level of working temperatures and other properties of polymer composite materials. This article discusses a methodology for experimental determination of the mechanical properties of carbon-based fiber-reinforced polymer composite materials, including the determination of the interlayer fracture toughness under loading under separation conditions using the doublecantilever beam method (DCB) and the fracture toughness under transverse shear conditions using the ENF (End-Notched Flexure) method and interlayer strength. The test results of samples of polymer composite materials with a carbon reinforcing filler with different surface densities are presented. The experimental data were used to identify the parameters of the VCCT (Virtual Crack Closure Technique) and CZM (Cohesive Zone Model) closure models used to describe the development of cracks in the composites under consideration. It was found that the parameters determining the strength of layered composites are such characteristics as interlayer strength and crack resistance. It was found that the decrease in the strength of individual layers of the composite does not always affect the current stress state of the entire structure, which is often difficult to detect experimentally, but can significantly affect the further behavior of the object under study provided that the crack develops further.

Discrete Cohesive Zone Model to Simulate Static Fracture in 2D Triaxially Braided Carbon Fiber Composites

2006 ◽  
Vol 40 (22) ◽  
pp. 2025-2046 ◽  
Author(s):  
De Xie ◽  
Amit G. Salvi ◽  
Ce Sun ◽  
Anthony M. Waas ◽  
Ari Caliskan
Keyword(s):  
Carbon Fiber ◽  
Cohesive Zone ◽  
Cohesive Zone Model ◽  
Fiber Composites ◽  
Zone Model ◽  
Carbon Fiber Composites ◽  
Static Fracture

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.

Cohesive Zone Model for the Interface of Multiwalled Carbon Nanotubes and Copper: Molecular Dynamics Simulation

2014 ◽  
Vol 5 (3) ◽  
Author(s):  
Ibrahim Awad ◽  
Leila Ladani
Keyword(s):  
Carbon Nanotubes ◽  
Normal Stress ◽  
Multiwalled Carbon Nanotubes ◽  
Cohesive Zone ◽  
Large Scale ◽  
Cohesive Zone Model ◽  
Dynamics Simulation ◽  
Zone Model ◽  
Multiwalled Carbon ◽  
Significant Difference

Due to their superior mechanical and electrical properties, multiwalled carbon nanotubes (MWCNTs) have the potential to be used in many nano-/micro-electronic applications, e.g., through silicon vias (TSVs), interconnects, transistors, etc. In particular, use of MWCNT bundles inside annular cylinders of copper (Cu) as TSV is proposed in this study. However, the significant difference in scale makes it difficult to evaluate the interfacial mechanical integrity. Cohesive zone models (CZM) are typically used at large scale to determine the mechanical adherence at the interface. However, at molecular level, no routine technique is available. Molecular dynamic (MD) simulations is used to determine the stresses that are required to separate MWCNTs from a copper slab and generate normal stress–displacement curves for CZM. Only van der Waals (vdW) interaction is considered for MWCNT/Cu interface. A displacement controlled loading was applied in a direction perpendicular to MWCNT's axis in different cases with different number of walls and at different temperatures and CZM is obtained for each case. Furthermore, their effect on the CZM key parameters (normal cohesive strength (σmax) and the corresponding displacement (δn) has been studied. By increasing the number of the walls of the MWCNT, σmax was found to nonlinearly decrease. Displacement at maximum stress, δn, showed a nonlinear decrease as well with increasing the number of walls. Temperature effect on the stress–displacement curves was studied. When temperature was increased beyond 1 K, no relationship was found between the maximum normal stress and temperature. Likewise, the displacement at maximum load did not show any dependency to temperature.

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