Presented by

YASHWANTH S and SANTOSH

NITTE MEENAKSHI INSTITUTE OF TECHNOLOGY

BANGALORE

Venue:M V JAYARAMAN COLLEGE OF ENGINEERING, BangaloreWednesday, 14th October 2014

OVERVIEW

Introduction.

Self Healing Technology.

Why It Is Necessary?

Procedure.

Materials used.

Types of Self healing.

Ways of healing.

Advantages and limitations.

Conclusion.

Literature views.

INTRODUCTION.When you cut yourself, it's amazing to watch how

quickly your body acts to mend the wound.

Immediately, your body works to pull the skin around the cut back together.

Immediately our body respond to self-healing power.

Here also a similar system, but replacing blood with resin and veins with tiny glass tubes, to fill in cracks or small holes in satellite skin.

Scientists are now developing a new type of composite material that will give those same self-healing qualities to SPACECRAFTS.

Self Healing Technology.Self- healing is the ability to repair damage in an

automatic and specific fashion without manual intervention. The ability of a material to be able to heal damages automatically and

autonomously is called SELF HEALING property.

self healing material can close the damage within their structure by restoring and maintaining its original mechanical properties.

Why It Is Necessary?Damage resulting from impact can cause a loss of

50-60% of the undamaged static strength.

Detection of low velocity impact damage is very difficult and it is also difficult to access the resulting deep cracks in the composite material to facilitate repair.

The damage can be divided into two types:

Macro damage.

Micro damage.

Macro Damage:

It is mainly results from extensive delaminating, ply-buckling and large-scale fracture and can be visually detected and repaired with reasonable ease.

Micro Damage:

It is barely visible, consisting of small delimitations, ply-cracks and fiber-fracture, occurs mainly inside the composite material, and is difficult to detect and repair.

Others kinds of damage are namely shear-cracks, delaminating, longitudinal matrix-splitting, fiber/matrix debonding, fiber fracture.

Procedure: Polymeric coating materials are particularly

susceptible to natural or artificial degradation. polymer degradation may come in the formation of micro cracking that would reduce material’s mechanical properties and shorten its lifetime.

To overcome this the glass tubes filled with Resins lie under the surface of the material and hence breaks when a crack is form on that surface. Hence the resins acts as a healing agent and heals material cracked.

Materials used.Composite Materials:Polymer composites are advanced materials that are

made from carbon, glass and a resin, such as epoxy, vinyl ester or urethane. Epoxy is a thermosetting polymer.

Microencapsulated healing agent:This is the glue that fixes the micro cracks formed in the

composite material.

Catalyst: In order to polymerize, the healing agent must come

into contact with a catalyst. A patented catalyst, called Grubbs‘ catalyst, is used for this self-healing material.

Types of Self healingIntrinsic Self-healing: Intrinsic self-healing means that the polymer matrix

themselves intrinsically have self-healing properties that can heal after damage occur, although it still

need external stimulation. so some materials under go physical or chemical interaction where rearrangements of bonds occurs.

Extrinsic Self-healing: In this condition the self healing agent is introduced

or pre-embedded into polymer matrix.

Beside encapsulation, self-healing agent could also loaded in pipeline within the matrix.

When crack occurs, mechanical force would destroy the capsule or pipeline and triggers the release of self-healing agent.

The self-healing agent would reach the site of cracking and interact chemically with polymer matrix to close

and heal the crack.

Ways of healing.Thermal Triggered Healing: a thermally triggered self-healing material was

prepared by blending a high-temperature epoxy resin with a thermoplastic polymer.

When a micro crack forms in the composite material, it will spread through the material.

By doing so, this crack will rupture the microcapsules and release the healing agent.

This healing agent will flow down through the crack and combine with catalyst, which initiates polymerization.

the self-healed composite material regained as much as 75 percent of its original strength.

Electrical Triggered Healing: In the case of Electrical triggering electricity sent

across the structure.

when the current travels around a crack, its resistance increases.

This heats the composite and the crack, which melts the healing agent, which then flows into the crack and returns the structure to 70% of its original strength.

This would lead to fuel savings, cutting costs for airlines and passengers and reducing carbon emissions too.

After healing

Healing process

Advantages: Provide continuous healing over lifetime.

Integrate the material surface without any ridges.

80-90 % recovery of mechanical strength.

Life period can be increased.

Limitations: Undesirable weight is going to add to the space

shuttle.

Sufficient number of hollow tubes destroys the integrity of original material.

once the healing agent has been used up, the material loses its self-healing ability.

Conclusion. when the surface gets destructed then the epoxy-

resin from the glass tube comes in contact with the curing agent and get solidifies at that area.

To get solidified , different healing process needs different condition like thermal energy, electrical energy and combination of these.

Air and atmospheric conditions is required for some of the healing process where as other healing process are independent.

This advanced technology is still under research in the field of Aircrafts. Our idea is to use these concepts on spacecrafts.

Literature views.

This type of technology was proposed in 2004 by

‘REAN GRIFFITH’ under his paper “Design and implementation of Self-Healing systems”.