28-06-2012, 05:16 PM
smart materials
smart materials in automobile seminar.doc (Size: 1.3 MB / Downloads: 72)
INTRODUCTION
Science and technology have made amazing developments in the design of electronics and machinery using standard materials, which do not have particularly special properties (i.e. steel, aluminum, gold). Imagine the range of possibilities, which exist for special materials that have properties scientists can manipulate. Some such materials have the ability to change shape or size simply by adding a little bit of heat, or to change from a liquid to a solid almost instantly when near a magnet; these materials are called smart materials. What are they? They are those materials that posses both intrinsic and extrinsic capabilities to respond to stimuli and environmental changes. They respond to changes in temperature, moisture, pH, magnetic Field, electric field, etc. The term “smart materials” encompasses a wide variety of materials, such as piezoelectric materials, magneto-rheostatic materials (MR), electro-rheostatic materials (ER), and shape memory alloys etc.
Like many scientific advances, smart fluids were discovered by accident. Researchers’ using marble and oil to construct a very high voltage switch in 1940’s noticed that as the switch operated, the marble eroded into a dust in the oil, which turns into from a liquid to a paste in the presence of high voltage. After the initial novelty wore off, interest in smart fluids languished through the 1970’s and 1980’s.
Such controllable fluids and materials whose rheology may vary by the application of the external inputs have long been seen as offering the possibility simple quite rapid response interfaces between electronic controls and mechanical systems. The automotive and aerospace industries were probably the first to identify the potential engineering application of smart fluids and material – Notably for vibration control, variable torque transmission, medical rehabilitation, and Chromogenic application. Nowadays, many additional avenues are been explored, e.g., civil engineering structures,Robotics and manufacturing and distributed structures.[1]
LITERATURE REVIEW
The first observation of the shape memory effect in materials occurred in the 1930's. A Swedish physicist by the name of Arne Olander discovered an interesting phenomenon when working with an alloy of gold (Au) and cadmium (Cd). The Au- Cd alloy was plastically deformed when cool and upon heating it returned to original or ‘memorized’ dimensional configuration. This phenomenon was called the Shape Memory Effect (SME) and the alloys that exhibited this behavior were called Shape Memory Alloys (SMA). At this time however, there were few, if any, practical uses of this type of alloys, until 1958, when researchers Chang and Read demonstrated the Shape Memory Effect at the Brussels World’s Fair. They showed that the SME could be used to perform mechanical work by cyclically lifting a weight using an Au-Cd SMA
Further research revealed other materials that also demonstrated this phenomenon. In 1962 the shape memory properties of Nickel Titanium alloys were discovered by accident at the US Naval Ordnance Laboratories. Although pure Nickel Titanium has very low ductility in the martensitic phase, the properties can be much modified by the addition of a small amount of a third element. This group of alloys is now known as Nitinol™ (Nickel-Titanium-Naval-Ordnance-Laboratories). NiTi SMAs proved to be less expensive, easier to work with and less dangerous from a health standpoint than previously discovered alloys. These factors led to a renewed interest in SMAs and their application. Companies recognized the potential of using the SME in engineering applications. As a result, starting in the 1970’s commercial products began to appear. The first commercial applications for this new material were static devices, like pipefittings. These fittings were applied first by the U.S. Air Force and later also the Navy used them for original equipment production and tube system. Also in the early 1970's a group of Brass (CuZnAl) alloys were discovered to exhibit shape memory properties. Although they were cheaper than Nitinol™ and able to perform at wider temperature ranges, they also has some disadvantages like lower work output and unwanted ageing, which made them less interesting for high power applications. Following these static applications, researchers began to propose SMA devices to perform dynamic tasks. The SMA devices began to play the role of sensors and actuators. In order to perform a dynamic task, the SMA must experience a cycle of heating, cooling, and deformation. As an example of this actuators were used in temperature regulation systems, in which the environmental temperature could be
used for thermal actuation of the SMA.
Recent research has focused on the improvement of Nitinol™ properties, especially to make it suitable for a wider range of temperatures. Also research concerning the application and control of SMA actuators in robotic systems has been conducted and expanded through the present.[1]
AN A-TO-Z GUIDE TO SMART MATERIALS
Smart Materials: Emerging Markets for Intelligent Gels, Ceramics, Alloys, and Polymers is your guide to the world of smart materials. In one handy volume it will give you a hard-headed assessment of new applications and markets ... And brief you on important developments related to dozens of materials in a wide range of categories, including:
Piezoelectric materials:
These ceramics or polymers are characterized by a swift, linear shape change in response to an electric field. The electricity makes the material expand or contract almost instantly. The materials have potential uses in actuators that control chatter in precision machine tools, improved robotic parts that move faster and with greater accuracy, smaller microelectronic circuits in machines ranging from computers to photolithography printers, and health-monitoring fibers for bridges, buildings, and wood utility poles. [2]
smart materials in automobile seminar.doc (Size: 1.3 MB / Downloads: 72)
INTRODUCTION
Science and technology have made amazing developments in the design of electronics and machinery using standard materials, which do not have particularly special properties (i.e. steel, aluminum, gold). Imagine the range of possibilities, which exist for special materials that have properties scientists can manipulate. Some such materials have the ability to change shape or size simply by adding a little bit of heat, or to change from a liquid to a solid almost instantly when near a magnet; these materials are called smart materials. What are they? They are those materials that posses both intrinsic and extrinsic capabilities to respond to stimuli and environmental changes. They respond to changes in temperature, moisture, pH, magnetic Field, electric field, etc. The term “smart materials” encompasses a wide variety of materials, such as piezoelectric materials, magneto-rheostatic materials (MR), electro-rheostatic materials (ER), and shape memory alloys etc.
Like many scientific advances, smart fluids were discovered by accident. Researchers’ using marble and oil to construct a very high voltage switch in 1940’s noticed that as the switch operated, the marble eroded into a dust in the oil, which turns into from a liquid to a paste in the presence of high voltage. After the initial novelty wore off, interest in smart fluids languished through the 1970’s and 1980’s.
Such controllable fluids and materials whose rheology may vary by the application of the external inputs have long been seen as offering the possibility simple quite rapid response interfaces between electronic controls and mechanical systems. The automotive and aerospace industries were probably the first to identify the potential engineering application of smart fluids and material – Notably for vibration control, variable torque transmission, medical rehabilitation, and Chromogenic application. Nowadays, many additional avenues are been explored, e.g., civil engineering structures,Robotics and manufacturing and distributed structures.[1]
LITERATURE REVIEW
The first observation of the shape memory effect in materials occurred in the 1930's. A Swedish physicist by the name of Arne Olander discovered an interesting phenomenon when working with an alloy of gold (Au) and cadmium (Cd). The Au- Cd alloy was plastically deformed when cool and upon heating it returned to original or ‘memorized’ dimensional configuration. This phenomenon was called the Shape Memory Effect (SME) and the alloys that exhibited this behavior were called Shape Memory Alloys (SMA). At this time however, there were few, if any, practical uses of this type of alloys, until 1958, when researchers Chang and Read demonstrated the Shape Memory Effect at the Brussels World’s Fair. They showed that the SME could be used to perform mechanical work by cyclically lifting a weight using an Au-Cd SMA
Further research revealed other materials that also demonstrated this phenomenon. In 1962 the shape memory properties of Nickel Titanium alloys were discovered by accident at the US Naval Ordnance Laboratories. Although pure Nickel Titanium has very low ductility in the martensitic phase, the properties can be much modified by the addition of a small amount of a third element. This group of alloys is now known as Nitinol™ (Nickel-Titanium-Naval-Ordnance-Laboratories). NiTi SMAs proved to be less expensive, easier to work with and less dangerous from a health standpoint than previously discovered alloys. These factors led to a renewed interest in SMAs and their application. Companies recognized the potential of using the SME in engineering applications. As a result, starting in the 1970’s commercial products began to appear. The first commercial applications for this new material were static devices, like pipefittings. These fittings were applied first by the U.S. Air Force and later also the Navy used them for original equipment production and tube system. Also in the early 1970's a group of Brass (CuZnAl) alloys were discovered to exhibit shape memory properties. Although they were cheaper than Nitinol™ and able to perform at wider temperature ranges, they also has some disadvantages like lower work output and unwanted ageing, which made them less interesting for high power applications. Following these static applications, researchers began to propose SMA devices to perform dynamic tasks. The SMA devices began to play the role of sensors and actuators. In order to perform a dynamic task, the SMA must experience a cycle of heating, cooling, and deformation. As an example of this actuators were used in temperature regulation systems, in which the environmental temperature could be
used for thermal actuation of the SMA.
Recent research has focused on the improvement of Nitinol™ properties, especially to make it suitable for a wider range of temperatures. Also research concerning the application and control of SMA actuators in robotic systems has been conducted and expanded through the present.[1]
AN A-TO-Z GUIDE TO SMART MATERIALS
Smart Materials: Emerging Markets for Intelligent Gels, Ceramics, Alloys, and Polymers is your guide to the world of smart materials. In one handy volume it will give you a hard-headed assessment of new applications and markets ... And brief you on important developments related to dozens of materials in a wide range of categories, including:
Piezoelectric materials:
These ceramics or polymers are characterized by a swift, linear shape change in response to an electric field. The electricity makes the material expand or contract almost instantly. The materials have potential uses in actuators that control chatter in precision machine tools, improved robotic parts that move faster and with greater accuracy, smaller microelectronic circuits in machines ranging from computers to photolithography printers, and health-monitoring fibers for bridges, buildings, and wood utility poles. [2]