The Encyclopedia of Smart Materials (ESM) contains the writings, thoughts, and work of many of the world's leading people (scientists, educators, chemists, engineers, innovative laboratories, and practitioners) working in the field of smart materials. The field of smart materials offers great potential for rapid introduction and implementation in a wide range.
ACTUATORS, PIEZOELECTRIC CERAMIC, FUNCTIONAL GRADIENT
Compositional gradients can be easily achieved by continuously adjusting the proportions of the reactants in the mixture. 8 and 9, respectively, and the associated bending displacement of the FGM piezoelectric actuator is shown in Figure 10.
ADAPTIVE COMPOSITE SYSTEMS: MODELING AND APPLICATIONS
(c) piezoelectric actuator configuration in checkerboard and line layouts; and (d) in-hull noise reduction for both actuation configurations. FLEXIBLE COMPOSITE SYSTEMS: MODELING AND APPLICATIONS 25 inside the hull as determined from.
ADAPTIVE SYSTEMS, ROTARY WING APPLICATIONS
A thin-walled cantilever beam is used to model the helicopter blade (8,9). The integrated design methodology of the distributed actuator was based on the inverse piezoelectric effect and aimed at the active control of the vibration characteristics of the vertical and lateral eigenbeams. The design enables rotor blade flap control by an actuator embedded in the blade itself.
AIRCRAFT CONTROL, APPLICATIONS OF SMART STRUCTURES
Nevertheless, a major contribution to the Wright brothers' success was their "smart structure" flight control system for the spin axis. At the same time, the shape of the airfoil creates a high static drag moment in this direction. When introduced, they are inferior to the best available state-of-the-art technologies at the time.
In this case, the efficiency of the system depends on the static aeroelastic efficiency of the actuated control surfaces. Compared to flutter, the aerodynamic efficiency of these surfaces is further reduced due to turbulent flow conditions. As described in (45), the correct shape of the surface in conjunction with the location of the plug axis also increases the stability of the oscillation.
Actuator position and stiffness variation for aeroelastic effectiveness vs. dynamic pressure
The crucial element of the all-movable surface using adaptive attachment stiffness is the attachment/drive. First, lifting forces create bending deformations in the direction of the lifting force. In the world of aerodynamics, designing the required roll and camber distribution for a desired lift at minimum drag is also an optimization task.
However, this can be solved by proper design of the interface between the passive and active structures. But the main difficulties are the stiffness and load limitations of the passive structure itself. It is also not correct to think that an active aeroelastic concept becomes more effective if the flexibility of the structure is increased.
ARCHITECTURE
The proposed organization also maintains the fundamental focus on implementing the traditional classification system. Intelligent Environments Designed Environments Intelligent environments consist of interactive behaviors and complex assemblies that often respond intelligently—materials combine traditional materials and systems “act” with intelligent materials and. Environmental conditions may be ambient or may be produced through a direct energy input.
Size/location. Regardless of the class of smart material, one of the most fundamental features that distinguish smart materials from traditional materials is the discrete size and direct action of the material. Since architectural design has traditionally involved integrated systems and materials—the building envelope construction depends on the building's structural system, the building's HVAC system depends on the envelope construction—then the greatest potential may come from the use of smart materials to remove. integrate certain components, behaviors or environments within the building. Fundamentally, actions can be discrete and direct - the minimum needed at the point and time for maximum effect.
BATTERY APPLICATIONS
However, when current flows through the cell, some of the energy is lost as waste heat due to polarization losses in the cell. Overvoltageη is a measure of the deviation of the cell voltage Eop from the equilibrium open circuit voltage Eoc. The available energyε of the cell is given by the product of the cell capacity Q and the average operating voltage Eop.
The equilibrium cell voltage Eoc and the capacity Q of a battery are determined by the intrinsic properties of the electrode materials. Instead, the cathode can react with the electrolyte due to the highly oxidized nature of the deeply charged Li1−xCoO2 cathode. The lithium extraction / insertion from / into the 8a tetra- hedral and 16c octahedral sites of the Li [Mn2] O4spinel oc- curs in two separate steps (16).
BIOMEDICAL APPLICATIONS
Research into biomedical applications of SMA started in the 1970s with animal studies initially, followed by clinical trials. On the other hand, the stiffness of superelastic Ti-Ni increases drastically after point B at the end of the loading plateau. The temperature of the valve and the flow rate of the water passing through the channel were measured.
Animal experiments were performed to study the fundamental functions and biocompatibility of the actuator. The pressure rose by 50 mmHg in the area locked by the actuator, corresponding to the width of the SMA plates: 18 mm (see Figure 23). The sensor is a layered medium, the construction of which is analogous to the construction of a human finger.
BIOMEDICAL SENSING
The ideal biosensor properties listed in Table 2 provide some of the driving forces for research in this area. Some of the same interactions, particularly using chemoreceptors, can be used to design drugs. Polymers selected for use in biosensors must meet many requirements: they must not interfere with the chemistry of the reaction in the sensor and must also be neutral and stabilizing for biological components used in the sensor, such as enzymes (21).
These systems are formed by first forming a reactive derivative of the target enzyme by attaching a polymerizable double bond, such as an acrylate, to the enzyme by reacting it with acryloyl chloride (Fig. 6). The polymer matrices used can be designed to control the diffusion of the substrate to the enzyme, and conductive polymers can transfer redox charges from enzyme active sites to electrode surfaces (19). Micromolar concentrations of H2O2 can be related to electrical signals of the order of several hundred nanoamperes.
BIOMIMETIC ELECTROMAGNETIC DEVICES
An examination of the wing surface reveals the presence of nanosized protrusions similar to the corneal nipples in insect eyes (Fig. 3). The flapping of butterfly wings produced a change in color proportional to the angle of the wing. Warm objects, such as mammals, emit energy in the infrared part of the electromagnetic spectrum.
In the crotalines, two infrared pit organs are placed on either side of the head between the eyes and upper jaw. In both publications, the function of the unique surface morphology covering the infrared pit organs has been speculated (see Fig. 8). The microwells of the IR well organ are approximately 300 nm in diameter and the scale ridges are spaced at 3.5 µm.
BIOSENSORS, POROUS SILICON
The layer is about 1 µm thick, and the silicon resistivity is 0.2 cm in all cases [reprinted with permission from (10)]. The dielectric function is not a constant, but strongly depends on the frequency of the external electric field. The real and imaginary part of the dielectric function can be accessed through reflectance measurements.
Illumination of the porous matrix by white light leads to a characteristic interference pattern in the reflection spectrum. It can be shown that the intensity of the transmitted light (a geometric series) gives a Lorentzian function. The number of edges in the observed wavelength range depends on the porosity and thickness of the porous layer.
CERAMICS, PIEZOELECTRIC AND ELECTROSTRICTIVE
Schematic of the longitudinal (a), transverse (a) and shear deformations (b) of the piezoelectric ceramic material under an applied electric field. For example, the domains become oriented in the crystallographic direction closest to the direction of the applied electric field. Mechanical deformations can be applied in different directions to obtain different components of the piezoelectric and electrostriction tensors.
However, multiple gauges must be used to obtain the full set of piezoelectric and electrostriction coefficients of the sample. A force acting on a moving sample surface (especially a thin ceramic film) can damage the sample. Comparison of electric field-induced deformation in a typical piezoelectric (PZT) and relaxor (0.9PMN–0.1PT).
CERAMICS, TRANSDUCERS
Just below the Curie temperature, the spontaneous polarization vector points in the [001] direction (tetragonal phase), below 5◦C it reorients to [011] (orthrombic phase) and below -90◦C to [111] (rhombohedral phase). This improvement in the piezoelectric effect is attributed to the increased ease of polarization reorientation in an electric field. One of the most important applications of piezoelectric materials is based on the field of ultrasonic echo (20,21).
An ultrasound image represents the tissue's mechanical properties, such as density and elasticity. The operating frequency of the transducer is directly related to the thickness and speed of sound in the piezoelectric materials used. Then a high voltage output can be taken from the small electrode and from one of the larger electrodes.
CHARACTERIZATION OF PIEZOELECTRIC CERAMIC MATERIALS
L. J ORDAN
For large signals, both the electrical displacement D and the polarization P are nonlinear functions of the field E. The specific symmetry of the unit cell determines the possibility of piezoelectricity in the crystal. A piezoelectric ceramic has only one type of piezoelectric matrix, regardless of the symmetry of the constituent crystals.
These measurements can be either static or dynamic, depending on the measurement system and the intended use of the ceramic. Characterization of the elastic, dielectric and electromechanical properties of piezoelectric ceramics is crucial for several reasons. Hinkley (NASA Langley Research Center) for his review of the manuscript and his helpful comments.
CHEMICAL INDICATING DEVICES
