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Developments 1926- 1990 Synthetic rubber. Polyvinyl chloride (PVC). New molding and extrusion techniques for plastics. Polystyrene. Polyethelene. continuous casting of steel, Plexiglass. Nylon in 1938. Teflon discovered by Roy Plunkett.
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Developments 1926- 1990 Synthetic rubber. Polyvinyl chloride (PVC). New molding and extrusion techniques for plastics. Polystyrene. Polyethelene. continuous casting of steel, Plexiglass. Nylon in 1938. Teflon discovered by Roy Plunkett. Fiberglass. Foam glass insulating material. Plastic contact lens. Vinyl floor covering. Aluminum-based metallic yard. Ceramic magnets. Basic oxygen process to refine steel making. Karl Zeigler invents new process for producing polyethelene. Dacron, plasticized PVC, and silicones manufactured by Dow Corning. Polypropylene (petroleum-based). Superpolymers (heat resistant). 1964 - Acrylic paint . Carbon fiber (used to reinforce materials in high temperature environment). Beryllium (hard metal) developed for heat shields in spacecraft, animal surgery, aircraft parts, etc. Sialon (ceramic material for high-speed cutting tools in metal machining). Soft bifocal contact lens in 1983. Synthetic skin. New composites and lightweight steel HIGH PERFORMANCE MATERIALS
SMART MATERIALS- which adjust to the requirements "smart materials" also called intelligent materials or active materials describes a group of material systems with unique properties. The technological field of “smart materials” is not transparent or clearly structured. It has evolved over the past decades with increasing pace during the 1990s to become what it is today. • Smart materials, Intelligent Materials, Active Materials, Adaptive Materials and to some extent “actuators” and “sensors” are almost always used interchangeably. • Active materials - two groups. 1. The “classical” active materials as viewed by the academic community and is characterized by the type of response these materials generate. 2. Consists of materials that respond to stimuli with a change in a key material property, eg.electrical conductivity or viscosity • [Mention of medicines, packed items which will indicate the life with change in time, environment, decay etc; dress materials which will adjust with the human conditions etc. etc.]
Smart Materials Also termed as Responsive Materials • "Smart" materials respond to environmental stimuli with particular changes in some variables. Also called responsive materials. Depending on changes in some external conditions, "smart" materials change either their properties (mechanical, electrical, appearance), their structure or composition, or their functions. Mostly, "smart" materials are embedded in systems whose inherent properties can be favorably changed to meet performance needs.
Smart Materials A smart material with variable viscosity may turn from a fluid which flows easily to a solid. A smart fluid developed in labs at the Michigan Institute of Technology
Self diagnostic materials Optic fibres composite Smart composites Smart tagged composites • Temperature changing materials Thermoelectric materials • Thickness changing fluids Magneto-Rehological fluids (MRFs) • References Intelligent MaterialsSmart materials workshop
Piezoelectric Materials 1. When a piezoelectric material is deformed, it gives off a small but measurable electrical discharge 2. When an electrical current is passed through a piezoelectric material it experiences a significant increase in size (up to a 4% change in volume) Most widely used as sensors in different environments To measure fluid compositions, fluid density, fluid viscosity, or the force of an impact Eg: Airbag sensor in modern cars- senses the force of an impact on the car and sends and electric charge deploying the airbag.
Electro-Rheostatic (ER) and Magneto-Rheostatic(MR) materials These materials are fluids, which can experience a dramatic change in their viscosity Can change from a thick fluid (similar to motor oil) to nearly a solid substance within the span of a millisecond when exposed to a magnetic or electric field; the effect can be completely reversed just as quickly when the field is removed.
Shape Memory Alloys (SMA) • Shape memory alloys (SMA's) are metals, which exhibit two very unique properties, pseudo-elasticity, and the shape memory effect. Arne Olander first observed these unusual properties in 1938 (Oksuta and Wayman 1938), but not until the 1960's were any serious research advances made in the field of shape memory alloys. The most effective and widely used alloys include NiTi (Nickel - Titanium), CuZnAl, and CuAlNi
Applications of Shape Memory Alloys • Aeronautical Applications: • Surgical Tools: • Muscle Wires
How Shape Memory Alloys Work The Martensite and Austenite phases
Microscopic and Macroscopic Views of the Two Phases of Shape Memory Alloys
Ferromagnetic Shape Memory Alloys (FSMA) – • Ferromagnetic Shape Memory Alloys (FSMA) Recently discovered class of actuator material, Magnetically driven actuation (field intensity varies, about 3KG and larger) and • large strains (around 6%). • FSMA are still in the development phase • Alloys in the Ni-Mn-Ga ternary. • FSMAs are ferromagnetic alloys which also support the shape memory effect.
SHAPE MEMORY EFFECT Implemented in: • Coffee pots • The space shuttle • Thermostats • Vascular Stets • Hydraulic Fittings (for Airplanes)
Pseudo-elasticity Applications in which pseudo-elasticity is used are: Eyeglass Frames Bra, Under wears Medical Tools Cellular Phone Antennae Orthodontic Arches Load Diagram of the pseudo-elastic effect Occurring
Advantages and Disadvantages of SMAs • Bio-compatibility • Diverse Fields of Application • Good Mechanical Properties (strong, corrosion resistant) Relatively expensive to manufacture and machine. Most SMA's have poor fatigue properties; this means that while under the same loading conditions (i.e. twisting, bending, compressing) a steel component may survive for more than one hundred times more cycles than an SMA element
ABOUT • METALLIC COATINGS • DIFFUSION COATINGS • ANODISING • POWDER COATING • THERMOPLASTICS • THERMOSETTING PLASTICS • ELASTOMERS printouts shall be supplied