scholarly journals A theory of anisotropic healing and damage mechanics of materials

2011 ◽  
Vol 468 (2137) ◽  
pp. 163-183 ◽  
Author(s):  
George Z. Voyiadjis ◽  
Amir Shojaei ◽  
Guoqiang Li ◽  
Peter I. Kattan
Keyword(s):  
Smart Materials ◽  
Inelastic Deformation ◽  
Damage Mechanics ◽  
Shape Memory Polymer ◽  
Healing Process ◽  
Continuum Damage Mechanics ◽  
Self Healing ◽  
Healing System ◽  
Damage Healing ◽  
Healing Processes

Self-healing smart materials have emerged into the research arena and have been deployed in industrial and biomedical applications, in which the modelling techniques and predicting schemes are crucial for designers to optimize these smart materials. In practice, plastic deformation is coupled with damage and healing in these systems, which necessitates a coupled formulation for characterization. The thermodynamics of inelastic deformation, damage and healing processes are incorporated here to establish the coupled constitutive equations for healing materials. This thermodynamic consistent formulation provides the designers with the ability to predict the irregular inelastic deformation of glassy polymers and damage and healing patterns for a highly anisotropic self-healing system. Moreover, the lack of a physically consistent method to measure and calibrate the healing process in the literature is addressed here. Within the continuum damage mechanics (CDM) framework, the physics of damage and healing processes is used to introduce the healing effect into the CDM concept and a set of two new anisotropic damage–healing variables are derived. These novel damage–healing variables together with the proposed thermodynamic consistent coupled theory constitute a well-structured method for accurately predicting the degradation and healing mechanisms in material systems. The inelastic and damage response for a shape memory polymer-based self-healing system is captured herein. While the healing experimental results are limited in the literature, the proposed theory provides the mathematical competency to capture the most nonlinear responses.

Mechanics of damage, healing, damageability, and integrity of materials: A conceptual framework

2016 ◽  
Vol 26 (1) ◽  
pp. 50-103 ◽  
Author(s):  
George Z Voyiadjis ◽  
Peter I Kattan
Keyword(s):  
Damage Mechanics ◽  
Healing Process ◽  
Continuum Damage Mechanics ◽  
Damage Variable ◽  
Continuum Damage ◽  
Variable Section ◽  
Damage Healing ◽  
Characterization Of Materials ◽  
New Formulation

In this work several new and fundamental concepts are proposed within the framework of continuum damage mechanics. These concepts deal primarily with the nature of the two processes of damage and healing along with introducing a consistent and systematic definition for the concepts of damageability and integrity of materials. Toward this end, seven sections are presented as follows: “The logarithmic damage variable” section introduces the logarithmic and exponential damage variables and makes comparisons with the classical damage variable. In “Integrity and damageability of materials” section a new formulation for damage mechanics is presented in which the two angles of damage–integrity and healing–damageability are introduced. It is shown that both the damage variable and the integrity variable can be derived from the damage–integrity angle while the healing variable and damageability variable are derived from the healing–damageability angle. “The integrity field” section introduces the new concept of the integrity field while “The healing field” section introduces the new concept of the healing field. These two fields are introduced as a generalization of the classical concepts of damage and integrity. “Unhealable damage and nondamageable integrity” section introduces the new and necessary concept of unrecoverable damage or unhealable damage. In this section the concept of permanent integrity or nondamageable integrity is also presented. In “Generalized nonlinear healing” section generalized healing is presented where a distinction is clearly made between linear healing and nonlinear healing. As an example of nonlinear healing the equations of quadratic healing are derived. Finally in “Dissection of the healing process” section a complete and logical/mathematical dissection is made of the healing process. It is hoped that these new and fundamental concepts will pave the way for new, consistent, and holistic avenues in research in damage mechanics and characterization of materials.

scholarly journals Study on the Elastoplastic Damage-Healing Coupled Constitutive Model of Mudstone

2017 ◽  
Vol 2017 ◽  
pp. 1-7
Author(s):  
Jie Xu ◽  
Jiawang Qu ◽  
Yufeng Gao ◽  
Ning Xu
Keyword(s):  
Mechanical Properties ◽  
Damage Mechanics ◽  
Chemical Interaction ◽  
Triaxial Compression ◽  
Healing Process ◽  
Great Influence ◽  
Radioactive Nuclide ◽  
Self Healing ◽  
Damage Healing ◽  
Elastoplastic Damage

Under the effect of high ground stress and water-rock chemical interaction, the fractures in the damaged mudstone wound undergo a self-healing process and recover the physical and mechanical properties, which has a significant impact on the wall-rock’s stability of high level radioactive waste repository and the migration of radioactive nuclide. According to the general thermodynamics and continuum damage mechanics, an internal variable describing mudstone healing properties is introduced and an elastoplastic damage-healing model reflecting mudstone deformation, damage, and self-healing evolution is put forward. This model is used to simulate the triaxial compression test of mudstone under different confining pressures, whose simulated results are compared with the test data. It is indicated that the model could embody the main mechanical properties of mudstone with the healing effect in an effective way, and the healing part of the model has a great influence on the simulated results.

Cohesive Zone Damage-Healing Model for Self-Healing Materials

2015 ◽  
Vol 784 ◽  
pp. 111-118 ◽  
Author(s):  
Rashid K. Abu Al-Rub ◽  
Ammar Alsheghri
Keyword(s):  
Cohesive Zone ◽  
Damage Mechanics ◽  
Continuum Damage Mechanics ◽  
Internal Crack ◽  
Self Healing ◽  
State Variable ◽  
Physically Based ◽  
Damage Healing ◽  
Effects Of Temperature ◽  
Healing Model

A cohesive zone damage-healing model (CZDHM) derived based on the laws of thermodynamics for self-healing materials is presented. The well-known nominal, healing, and effective configurations of classical continuum damage mechanics are extended to self-healing materials. A new physically-based internal crack healing state variable is proposed for describing the healing evolution within the crack cohesive zone. The effects of temperature, crack-closure, and resting time on the healing behavior are discussed. Numerical examples are conducted to show the various novel features of the formulated CZDHM.

Cyclic Viscoplastic-Viscodamage Analysis of Shape Memory Polymers Fibers With Application to Self-Healing Smart Materials

2012 ◽  
Vol 80 (1) ◽  
Author(s):  
Amir Shojaei ◽  
Guoqiang Li ◽  
George Z. Voyiadjis
Keyword(s):  
Shape Memory ◽  
Smart Materials ◽  
Damage Mechanics ◽  
Shape Memory Polymer ◽  
Smart Material ◽  
Stress Recovery ◽  
Self Healing ◽  
Material Systems ◽  
Damage Process ◽  
Smart Material Systems

The cold-drawn, programmed shape memory polymer (SMP) fibers show excellent stress recovery property, which promotes their application as mechanical actuators in smart material systems. A full understanding of the thermomechanical-damage responses of these fibers is crucial to minimize the trial-and-error manufacturing processes of these material systems. In this work, a multiscale viscoplastic-viscodamage theory is developed to predict the cyclic mechanical responses of SMP fibers. The proposed viscoplastic theory is based on the governing relations for each of the individual microconstituents and establishes the microscale state of the stress and strain in each of the subphases. These microscale fields are then averaged through the micromechanics framework to demonstrate the macroscale constitutive mechanical behavior. The cyclic loss in the functionality of the SMP fibers is interpreted as the damage process herein, and this cyclic loss of stress recovery property is calibrated to identify the state of the damage. The continuum damage mechanics (CDM) together with a thermodynamic consistent viscodamage theory is incorporated to simulate the damage process. The developed coupled viscoplastic-viscodamage theory provides an excellent correlation between the experimental and simulation results. The cyclic loading-damage analysis in this work relies on the underlying physical facts and accounts for the microstructural changes in each of the micro constituents. The established framework provides a well-structured method to capture the cyclic responses of the SMP fibers, which is of utmost importance for designing the SMP fiber-based smart material systems.

A Semi-Analytic Solution for Self-Healing Concrete Beams Through Stress Spectral Decomposition

2018 ◽  
Vol 10 (07) ◽  
pp. 1850077
Author(s):  
A. Kazemi ◽  
M. Baghani ◽  
H. Shahsavari ◽  
S. Sohrabpour
Keyword(s):  
Cross Section ◽  
Spectral Decomposition ◽  
Damage Mechanics ◽  
Concrete Beam ◽  
Rectangular Cross Section ◽  
Closed Form Solution ◽  
The Self ◽  
Continuum Damage ◽  
Self Healing ◽  
Damage Healing

Continuum damage-healing mechanics (CDHM) is used for phenomenological modeling of self-healing materials. Self-healing materials have a structural capability to recover a part of the damage for increasing materials life. In this paper, a semi-analytic modeling for self-healing concrete beam is performed. Along this purpose, an elastic damage-healing model through spectral decomposition technique is utilized to investigate an anisotropic behavior of concrete in tension and compression. We drive an analytical closed-form solution of the self-healing concrete beam. The verification of the solution is shown by solving an example for a simply supported beam having uniformly distributed the load. Finally, a result of a self-healing concrete beam is compared to elastic one to demonstrate the capability of the proposed analytical method in simulating concrete beam behavior. The results show that for the specific geometry, the self-healing concrete beam tolerates 21% more weight, and the deflection of the entire beam up to failure load is about 27% larger than elastic solution under ultimate elastic load for both I-beam and rectangular cross-section. Comparison of Continuum Damage Mechanics (CDM) solution with CDHM solution of beam shows that critical effective damage is decreased by 32.4% for a rectangular cross-section and by 24.2% for I-shape beam made of self-healing concrete.

Shape memory polymer-based self-healing triboelectric nanogenerator

2015 ◽  
Vol 8 (12) ◽  
pp. 3605-3613 ◽  
Author(s):  
Jeong Hwan Lee ◽  
Ronan Hinchet ◽  
Sung Kyun Kim ◽  
Sanghyun Kim ◽  
Sang-Woo Kim
Keyword(s):  
Shape Memory ◽  
Shape Memory Polymer ◽  
Healing Process ◽  
Triboelectric Nanogenerator ◽  
Self Healing

We introduce a new smart SMP–TENG structure and studied its degradation and healing process. The SMP improves the endurance and lifetime, and thus demonstrates the huge potential of self-healing SMP–TENGs.

scholarly journals A continuum damage mechanics framework for modeling micro-damage healing

2012 ◽  
Vol 49 (3-4) ◽  
pp. 492-513 ◽  
Author(s):  
Masoud K. Darabi ◽  
Rashid K. Abu Al-Rub ◽  
Dallas N. Little
Keyword(s):  
Damage Mechanics ◽  
Continuum Damage Mechanics ◽  
Continuum Damage ◽  
Damage Healing

scholarly journals A homeostatic-driven turnover remodelling constitutive model for healing in soft tissues

2016 ◽  
Vol 13 (116) ◽  
pp. 20151081 ◽  
Author(s):  
Ester Comellas ◽  
T. Christian Gasser ◽  
Facundo J. Bellomo ◽  
Sergio Oller
Keyword(s):  
Constitutive Model ◽  
Damage Mechanics ◽  
Healing Rate ◽  
Soft Tissues ◽  
Healing Process ◽  
Mechanical Damage ◽  
Continuum Damage Mechanics ◽  
Biological Tissues ◽  
Mechanical Stimuli ◽  
Open System Thermodynamics

Remodelling of soft biological tissue is characterized by interacting biochemical and biomechanical events, which change the tissue's microstructure, and, consequently, its macroscopic mechanical properties. Remodelling is a well-defined stage of the healing process, and aims at recovering or repairing the injured extracellular matrix. Like other physiological processes, remodelling is thought to be driven by homeostasis, i.e. it tends to re-establish the properties of the uninjured tissue. However, homeostasis may never be reached, such that remodelling may also appear as a continuous pathological transformation of diseased tissues during aneurysm expansion, for example. A simple constitutive model for soft biological tissues that regards remodelling as homeostatic-driven turnover is developed. Specifically, the recoverable effective tissue damage, whose rate is the sum of a mechanical damage rate and a healing rate, serves as a scalar internal thermodynamic variable. In order to integrate the biochemical and biomechanical aspects of remodelling, the healing rate is, on the one hand, driven by mechanical stimuli, but, on the other hand, subjected to simple metabolic constraints. The proposed model is formulated in accordance with continuum damage mechanics within an open-system thermodynamics framework. The numerical implementation in an in-house finite-element code is described, particularized for Ogden hyperelasticity. Numerical examples illustrate the basic constitutive characteristics of the model and demonstrate its potential in representing aspects of remodelling of soft tissues. Simulation results are verified for their plausibility, but also validated against reported experimental data.

Fatigue response of a solid state self-healing resin

2020 ◽  
pp. 096739112095509
Author(s):  
Mohd Suzeren Md Jamil ◽  
Noor Nabilah Muhamad ◽  
Wan Naqiuddin Wan Zulrushdi
Keyword(s):  
Fatigue Life ◽  
Solid State ◽  
Fatigue Behavior ◽  
Fatigue Cracks ◽  
Healing Process ◽  
Fatigue Tests ◽  
Self Healing ◽  
Healing System ◽  
Healing Agent ◽  
Modified Epoxy

The present work verified the capability of a solid state self-healing system for retarding or arresting fatigue cracks in epoxy materials subjected to cyclic loading at room temperature. A solid state self-healing material is demonstrated using a thermosetting epoxy polymer which was modified by incorporating a linear thermoplastic polydiglycidyl ether bisphenol-A (PDGEBA) as a healing agent. The stress-controlled constant amplitude (CA) tensile fatigue behavior at stress ratio, R = 0.1 and frequency 10 Hz for both the neat and the modified epoxy was investigated. Fatigue life and residual strength degradation were continuously monitored during the fatigue tests. The modified epoxy fatigue life was shown to be increased by ∼50% after healing periods. The fatigue-healing process was proven through the surface and cross-section resin morphology analyses using microscopy optic and scanning electron microscope (SEM). On the whole, the solid state self-healing system has proven to be very effective in obstructing fatigue crack propagation, effectively improved the self-healing polymeric material to achieve higher endurance limits.

Molecular Self-Healing Processes in Polymers

2004 ◽  
Vol 851 ◽  
Author(s):  
M. Chipara ◽  
K. Wooley
Keyword(s):  
Electron Spin Resonance ◽  
Healing Process ◽  
The Other ◽  
Self Healing ◽  
Polymeric Matrices ◽  
Multi Scale ◽  
Spin Resonance ◽  
Molecular Scale ◽  
Living Polymers ◽  
Healing Processes

ABSTRACTA critical review of self-healing processes in polymers and composites based on polymeric matrices is presented. Two self-healing processes are analyzed, one “operating” within micron range and the other at molecular scale. Preliminary data on the molecular self-healing process in living polymers, as obtained by electron spin resonance are discussed. The possibility to develop a multi-scale self-healing material is suggested.

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