Finite Element Modelling and Analysis of Micro-Capsule Based Self-Healing Polymeric Composites

2018 ◽  
Vol 10 (6) ◽  
Author(s):  
J. Lilly Mercy ◽  
S. Prakash
Keyword(s):  
Polymer Matrix ◽  
Healing Process ◽  
Polymeric Composites ◽  
Polymerization Reaction ◽  
Self Healing ◽  
Functional Composites ◽  
Laminate Theory ◽  
Static Mechanical ◽  
Healing Agent ◽  
The Many

Self-healing polymeric composites are a class of functional composites which heal itself during damage. Out of the many methods of self-healing, micro-capsule based self-healing process is the proven and established method where the healing agent stored in the capsule breaks and seals up the gap after the polymerization reaction with the suitable catalyst. The incorporation of the capsule in a polymer matrix in a random fashion makes it challenging to model the composite material. This paper explains the modelling and simulation of the self-healing composite using MIDAS NFX FEA software. The effect of self-healing composition - micro-capsule size and concentration on the static mechanical properties of the composite is explored. The capsules are integrated in the polymer matrix as a representative volume element using the rule of mixtures. The classical laminate theory was used to identify the critical ply failure.

Numerical investigation into effect of self-healing composite microcapsules thickness and diameter on their failure strength

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Raj Kumar Pittala ◽  
Satish Ben B. ◽  
Syam Kumar Chokka ◽  
Niranjan Prasad
Keyword(s):  
Matrix Composite ◽  
Polymer Matrix ◽  
Shell Thickness ◽  
Polymer Matrix Composite ◽  
Thickness Effect ◽  
Failure Strength ◽  
Self Healing ◽  
Content Type ◽  
Reinforced Polymer ◽  
Healing Agent

Purpose Microcapsule-embedded autonomic healing materials have the ability to repair microcracks when they come into contact with the crack by releasing the healing agent. The microcapsules with specific shape and thickness effect in releasing healing agent to the cracked surfaces. Thus, the purpose of this paper is to know the load bearing capacity of the self-healing microcapsules and the stresses developed in the material. Design/methodology/approach In the present study, self-healing microcapsule is modelled and integrated with the polymer matrix composite. The aim of the present study is to investigate failure criteria of Poly (methyl methacrylate) microcapsules by varying the shell thickness, capsule diameter and loading conditions. The strength of the capsule is evaluated by keeping the shell thickness as constant and varying the capsule diameter. Uniformly distributed pressure loads were applied on the capsule-reinforced polymer matrix composite to assess the failure strength of capsules and composite. Findings It is observed from the results that the load required to break the capsules is increasing with the increase in capsule diameter. The failure strength of microcapsule with 100 µm diameter and 5 µm thickness is observed as 255 MPa. For an applied load range of 40–160 N/mm2 on the capsules embedded composite, the maximum stress developed in the capsules is observed as 308 MPa. Originality/value Failure strengths of microcapsules and stresses developed in the microcapsule-reinforced polymer composites were evaluated.

scholarly journals Tracking capsule activation and crack healing in a microcapsule-based self-healing polymer

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
S. A. McDonald ◽  
S. B. Coban ◽  
N. R. Sottos ◽  
P. J. Withers
Keyword(s):  
Healing Process ◽  
Polymeric Materials ◽  
Time Lapse ◽  
Repair Process ◽  
Three Dimensions ◽  
Crack Plane ◽  
Self Healing ◽  
Crack Healing ◽  
Healing Agent ◽  
First Time

AbstractStructural polymeric materials incorporating a microencapsulated liquid healing agent demonstrate the ability to autonomously heal cracks. Understanding how an advancing crack interacts with the microcapsules is critical to optimizing performance through tailoring the size, distribution and density of these capsules. For the first time, time-lapse synchrotron X-ray phase contrast computed tomography (CT) has been used to observe in three-dimensions (3D) the dynamic process of crack growth, microcapsule rupture and progressive release of solvent into a crack as it propagates and widens, providing unique insights into the activation and repair process. In this epoxy self-healing material, 150 µm diameter microcapsules within 400 µm of the crack plane are found to rupture and contribute to the healing process, their discharge quantified as a function of crack propagation and distance from the crack plane. Significantly, continued release of solvent takes place to repair the crack as it grows and progressively widens.

scholarly journals Biological Self-Healing of Cement Paste and Mortar by Non-Ureolytic Bacteria Encapsulated in Alginate Hydrogel Capsules

Materials ◽  
2020 ◽  
Vol 13 (17) ◽  
pp. 3711
Author(s):  
Mohammad Fahimizadeh ◽  
Ayesha Diane Abeyratne ◽  
Lee Sui Mae ◽  
R. K. Raman Singh ◽  
Pooria Pasbakhsh
Keyword(s):  
Cement Paste ◽  
Healing Process ◽  
Cementitious Materials ◽  
The Self ◽  
Self Healing ◽  
Alkaline Conditions ◽  
Healing Agent ◽  
Encapsulated Bacteria ◽  
The Right

Crack formation in concrete is one of the main reasons for concrete degradation. Calcium alginate capsules containing biological self-healing agents for cementitious materials were studied for the self-healing of cement paste and mortars through in vitro characterizations such as healing agent survivability and retention, material stability, and biomineralization, followed by in situ self-healing observation in pre-cracked cement paste and mortar specimens. Our results showed that bacterial spores fully survived the encapsulation process and would not leach out during cement mixing. Encapsulated bacteria precipitated CaCO3 when exposed to water, oxygen, and calcium under alkaline conditions by releasing CO32− ions into the cement environment. Capsule rupture is not required for the initiation of the healing process, but exposure to the right conditions are. After 56 days of wet–dry cycles, the capsules resulted in flexural strength regain as high as 39.6% for the cement mortar and 32.5% for the cement paste specimens. Full crack closure was observed at 28 days for cement mortars with the healing agents. The self-healing system acted as a biological CO32− pump that can keep the bio-agents retained, protected, and active for up to 56 days of wet-dry incubation. This promising self-healing strategy requires further research and optimization.

scholarly journals Self-healing of bio-cementitious mortar incubated within neutral and acidic soil

2021 ◽  
Vol 54 (2) ◽  
Author(s):  
Mohamed Esaker ◽  
Omar Hamza ◽  
Adam Souid ◽  
David Elliott
Keyword(s):  
Soil Ph ◽  
Healing Process ◽  
Chemical Exposure ◽  
Acidic Soil ◽  
Self Healing ◽  
Chemical Attack ◽  
Before And After ◽  
Ground Conditions ◽  
Neutral Soil ◽  
Healing Agent

AbstractThe efficiency of bio self-healing of pre-cracked mortar specimens incubated in sand was investigated. The investigation examined the effect of soil pH representing industrially recognised classes of exposure, ranging from no risk of chemical attack (neutral pH ≈ 7) to very high risk (pH ≈ 4.5). Simultaneously, the soil was subjected to fully and partially saturated cycles for 120 days to resemble groundwater-level fluctuation. Bacillus subtilis with nutrients were impregnated into perlite and utilised as a bacterial healing agent. The healing agent was added to half of the mortar specimens for comparison purposes. Mineral precipitations were observed in both control and bio-mortar specimens, and the healing products were examined by SEM–EDX scanning. The healing ratio was evaluated by comparing (1) the repair rate of the crack area and (2) by capillary water absorption and sorptivity index—before and after incubation. The results indicated that bacteria-doped specimens (bio-mortar) exhibited the most efficient crack-healing in all incubation conditions i.e. different chemical exposure classes. In the pH neutral soil, the average healing ratios for the control and bio-mortar specimens were 38% and 82%, respectively. However, the healing ratio decreased by 43% for specimens incubated in acidic soil (pH ≈ 4) compared with specimens incubated in neutral soil (pH ≈ 7). The study implies that bio self-healing is generally beneficial for concrete embedded within soil; however, aggressive ground conditions can inhibit the healing process.

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.

scholarly journals Detecting the Activation of a Self-Healing Mechanism in Concrete by Acoustic Emission and Digital Image Correlation

2013 ◽  
Vol 2013 ◽  
pp. 1-10 ◽  
Author(s):  
E. Tsangouri ◽  
D. G. Aggelis ◽  
K. Van Tittelboom ◽  
N. De Belie ◽  
D. Van Hemelrijck
Keyword(s):  
Acoustic Emission ◽  
Digital Image Correlation ◽  
Digital Image ◽  
Crack Formation ◽  
Healing Process ◽  
Image Correlation ◽  
Activation Process ◽  
Self Healing ◽  
Emission Analysis ◽  
Healing Agent

Autonomous crack healing in concrete is obtained when encapsulated healing agent is embedded into the material. Cracking damage in concrete elements ruptures the capsules and activates the healing process by healing agent release. Previously, the strength and stiffness recovery as well as the sealing efficiency after autonomous crack repair was well established. However, the mechanisms that trigger capsule breakage remain unknown. In parallel, the conditions under which the crack interacts with embedded capsules stay black-box. In this research, an experimental approach implementing an advanced optical and acoustic method sets up scopes to monitor and justify the crack formation and capsule breakage of concrete samples tested under three-point bending. Digital Image Correlation was used to visualize the crack opening. The optical information was the basis for an extensive and analytical study of the damage by Acoustic Emission analysis. The influence of embedding capsules on the concrete fracture process, the location of capsule damage, and the differentiation between emissions due to capsule rupture and crack formation are presented in this research. A profound observation of the capsules performance provides a clear view of the healing activation process.

Computational Analysis of Self-Healing in a Polymer Matrix With Microvascular Networks

2008 ◽  
Author(s):  
Jose Martinez Lucci ◽  
R. S. Amano ◽  
Pradeep Rohatgi
Keyword(s):  
Polymer Matrix ◽  
Mechanical Performance ◽  
Polymer Matrix Composites ◽  
Self Healing ◽  
Matrix Composites ◽  
Microvascular Networks ◽  
Microvascular Network ◽  
Matrix Surface ◽  
The Matrix ◽  
Healing Agent

For the last decade, many researchers have been working to develop self-healing materials, and have obtained good results in the field of polymers, these components with microencapsulated healing agent have exhibited noticeable mechanical performance and regenerative property The research described in this paper applies the concept of self healing to simulate self healing polymer matrix composites, with the aid of models developed by the authors for the manufacturing processes and self-healing behavior. The development of self-healing is a novel idea that has not been totally explored in great detail yet. The concept of self-healing described in this paper consists of simulation of a healing agent dicyclopentadiene (DCPD) inside of a microvascular network within a polymer matrix coating with catalyst forming a self-healing composite (SHC). When this SHC is damaged or cracked, the healing agent by capillary action will flow inside of the microvascular network; when the liquid enter in contact with the catalyst will form a polymer structure and sealing the crack. The study consists of theoretical analysis and Computational Fluid Dynamics of a self-healing polymer. The objective of the study reported here was to find the influence and efficiency of the microvascular network in healing a polymer matrix. To check this effect a computational model was created to simulate the healing treatment, thus a crack was created on the matrix surface piercing the microvascular network filled with healing agent and the method to simulate healing behavior of the composite allows assessment of the effects of the autonomously repairing repeated damage events.

Modeling microcapsule-enabled self-healing cementitious composite materials using discrete element method

2017 ◽  
Vol 26 (2) ◽  
pp. 340-357 ◽  
Author(s):  
Shuai Zhou ◽  
Hehua Zhu ◽  
J Woody Ju ◽  
Zhiguo Yan ◽  
Qing Chen
Keyword(s):  
Discrete Element Method ◽  
Healing Process ◽  
Compressive Loading ◽  
Discrete Element ◽  
Cementitious Materials ◽  
Self Healing ◽  
Healing Effect ◽  
Healing Agent ◽  
Damage Healing ◽  
Element Method

Concrete with a micro-encapsulated healing agent is appealing due to its self-healing capacity. The discrete element method (DEM) is emerging as an increasingly used approach for investigating the damage phenomenon of materials at the microscale. It provides a promising way to study the microcapsule-enabled self-healing concrete. Based on the experimental observation and DEM, a three-dimensional damage-healing numerical model of microcapsule-enabled self-healing cementitious materials under compressive loading is proposed. The local healing effect can be simulated in our model, as well as the stress concentration effect and the partial healing effect. The healing variable of the DEM model is developed to describe the healing process. We examine the dependence of the mechanical properties of the microcapsule-enabled self-healing material on (a) the stiffness of the solidified healing agent, (b) the strength of the solidified healing agent, (c) the initial damage of specimens, and (d) the partial healing effect. In particular, the proposed numerical damage-healing model demonstrates the potential capability to explain and simulate the physical behavior of microcapsule-enabled self-healing materials on the microscale.

Mechanical Properties of a Microcapsule-Containing Epoxy for Self-Healing Applications

2011 ◽  
Vol 239-242 ◽  
pp. 1794-1798 ◽  
Author(s):  
Xing Liu ◽  
Jong Keun Lee
Keyword(s):  
Mechanical Properties ◽  
Polymer Matrix ◽  
Volume Fraction ◽  
Dynamic Mechanical Properties ◽  
Interfacial Interaction ◽  
Self Healing ◽  
Dynamic Mechanical ◽  
Healing Agent

The addition of microencapsulated healing agent or catalyst in a polymer matrix can potentially change its mechanical properties and processing characteristics. The extent of this change depends on the volume fraction of the additives, the level of interfacial interaction, and the inherent properties of the additives. For a self-healing concept to be viable, the healing performance should be achieved without compromising the overall processing and mechanical properties of the polymer matrix. In this study, tensile and dynamic mechanical properties were investigated and discussed for an amine-cured epoxy dispersed with different loadings of microcapsules.

scholarly journals Self-Repairing Composites for Corrosion Protection: A Review on Recent Strategies and Evaluation Methods

Materials ◽  
2019 ◽  
Vol 12 (17) ◽  
pp. 2754 ◽  
Author(s):  
P ◽  
Al-Maadeed
Keyword(s):  
Electrochemical Impedance ◽  
Protective Coatings ◽  
Healing Process ◽  
Cellulose Nanofibers ◽  
Aloe Vera ◽  
Immersion Test ◽  
The Self ◽  
Self Healing ◽  
Metal Substrates ◽  
Healing Agent

The use of self-healing coatings to protect metal substrates, such as aluminum alloys, stainless steel, carbon steel, and Mg alloys from corrosion is an important aspect for protecting metals and for the economy. During the past decade, extensive transformations on self-healing strategies were introduced in protective coatings, including the use of green components. Scientists used extracts of henna leaves, aloe vera, tobacco, etc. as corrosion inhibitors, and cellulose nanofibers, hallyosite nanotubes, etc. as healing agent containers. This review gives a concise description on the need for self-healing protective coatings for metal parts, the latest extrinsic self-healing strategies, and the techniques used to follow-up the self-healing process to control the corrosion of metal substrates. Common techniques, such as accelerated salt immersion test and electrochemical impedance spectroscopy (EIS), for evaluating the self-healing process in protective coatings are explained. We also show recent advancements procedures, such as scanning vibrating electrode technique (SVET) and scanning electrochemical microscopy (SECM), as successful techniques in evaluating the self-healing process in protective coatings.

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