Carbon fiber reinforced polymer (CFRP) has been recently applied to not only wing, but also fan blades of turbo fan engines. To prevent impact force, leading edge of titanium was often mounted on the CFRP fan blades with adhesive force. In order to enhance the joining strength, a joining method with carbon fiber reinforced interface has
been developed. By using nickel-coated carbon fibers, a joining sample with carbon fiber-reinforced interface between CFRP and CFRM has been successfully developed. The joining sample with nickel-coated carbon fiber interface exhibits the high tensile strength, which was about 10 times higher than that with conventional adhesion.
On the other hand, Al-welding methods to steel, Cu and Ti with carbon fiber reinforced interface have been successfully developed to lighten the parts of machines of racing car and airplane. Carbon fibers in felt are covered with metals to protect the interfacial reaction. The first step of the welding method is that the Al coated felt is contacted and wrapped with molten aluminum solidified under gravity pressure, whereas the second step is that the felt with double layer of Ni and Al is contacted and wrapped with molten steel (Cu or Ti) solidified under gravity pressure. Tensile strength of Al-Fe (Cu or Ti) welded sample with carbon fiber reinforced interface is higher than those of Al-Fe (Cu or Ti) welded sample.
KEYWORDS: Glasses, Silica, Electron beams, LCDs, Chemical species, Liquid crystals, Beam propagation method, Silicon, Signal detection, Process engineering
An influence of electron beam (EB) irradiation on the crack generation and propagation of transparent glasses are
studied by using a standard indentation fracture method. The thin (less than 0.5mm) transparent glass is used for
substrate of more than 100 inches crystal liquid display. However, it is difficult to product ultra thin and large-size
substrate without fracture. Therefore, these glasses have been expected to enhance the fracture toughness of
substrate for the displays.
As results, EB irradiation, which is one of short-time treatments of dry process at low temperature, increases the
crack nucleation energy of these glasses, although the EB irradiation does not change the crack propagation energy
of these glasses. The EB irradiation generates dangling bonds in these glasses. Partial relaxation of the residual
strain occurs around these dangling bonds in the silica network structure. If the inter-atomic distance of the
stronger metal-oxygen pairs becomes optimum on the potential curve of these glasses, the relaxation increases the
bonding energy of the network structure. Evidently, the enhancement of crack nucleation energy is mainly due to
an increase in the bonding energy for the stronger metal-oxygen atomic pairs in the atomic network structure, as
well as the relaxation of the network structure.
Perfluorosulfonic Acid (PFSA) film, commonly used in the Polymer Electrolyte Fuel Cells (PEFC), indicates
conductance of proton and permeability of H2O. In this study a mechanical composite mover device with this PFSA and
hydrogen storage alloy (HSA) thin films was made up for expecting the movement driven by volume change in the
course of hydrogen migration between PFSA and HSA layers. Hydrogen storage alloy, such as LaNi5 indicates as much
as 25% of volume change in the course of H2 absorption in gas phase. Using this characteristics, a mechanical mover
device was made of PFSA film of an electrolyte polymer sandwiched by hydrogen storage alloy thin films with Au-Pd
intermediate layers. The mover device was operated by migrating hydrogen ions from the PFSA layer to the HSA layer,
which were generated by electrolysis of H2O in a PFSA layer. Electrical potential was given from the outsides lead
wires. All experiments were carried out in the water. We confirmed large interesting movement generated by migration
of hydrogen ion by applying electric potentials.
Recently we proposed a mechanical mover device in a unimorph structure with powder hydrogen storage alloy dispersed.
A silicone rubber sheet with the alloy was piled up on another pure silicone rubber sheet, then mechanical movement was
generated by hydrogen gas absorption and desorption. Because the response of the movement was slow, therefore, in this
research we tested the additive effect of catalyst of Pd-Al2O3 powder into the hydrogen storage alloy powder before
mixing with rubber. The mover device with the catalyst indicated drastically modified responses, such as higher initial
moving rate and also larger displacement. The results suggested the possibility of the device for medical purpose such as
catheter because of a powerful but tender characteristic of the device.
An effect of electron beam (EB) irradiation on wettability was studied for polypropylene for biomedical application. EB
irradiation enhanced the wettability on polypropylene samples. To discuss the effect, the wettability was evaluated by
using contact angle of sessile drop. EB irradiation decreased the contact angle. Based on ESR results, the effects of
electron beam on the wettability were discussed. EB irradiation broke the weakly bonded pairs and formed the dangling
bonds in polypropylene.
Effects of sheet electron beam irradiation on impact strength and wettability of alkali-free glass were studied. The irradiation, which was one of short-time treatments at low temperature below boiling point of water, enhanced impact value, whereas it decreased contact angle of alkali-free glass surface. EB irradiation also enhanced wettability and mist resistance.
Hydrogen storage alloy, such as LaNi5 indicates as much as 25% of volume change in the course of H2 absorption and desorption. We examined to apply this phenomenon to a mechanical mover device as a driving force controlled by the amount of hydrogen in the alloy. In this study a unimorph structural mover device was tested using HSA thin film deposited on an inert substrate. We confirmed displacements generating drastically large stresses by applying H2 gas. While the amount of hydrogen in the alloy is a function of H2 pressure and temperature, we also tried to control the hydrogen amount in the HSA by electric current directly applied through the film in a closed system. We report discussions on results with precise relationship between current and displacement under different temperatures. Displacement can be achieved by the temperature change caused by the electric current placed under ambient H2 pressure, therefore, the results indicate the possibility of mover devices with simple structure similar to an artificial muscle controlled by electric current. From the results obtained, the test device was expected as an artificial muscle driven by hydrogen sorption reactions, which could be also controlled by electric current.
An effect of electron beam irradiation on intelligent properties including mist resistance, wetting and hardness were studied for polymers. The electron beam irradiation decreased the time to clear vision on the misted polymers samples. The treatment was conformed to show the mist resistance of the polymer. To discuss the effect of electron beam on mist resistance, the water wetting indicated by the surface energy was evaluated by using contact angle of sessile drop. Based on ESR results, the effects of electron beam on the mist resistance were discussed. Electron beam irradiation broke the weakly bonded pairs in polymer and formed the dangling bonds. In addition, EB-irradiation enhanced Vickers’ hardness for polycarbonate.
In this study, the effects of surface treatments were investigated on the mechanical response of the LaNi5 thin film actuator deposited on polyimide substrates. Since controlling the hydrogen concentration in film by reversible pressure change drives this actuator, this film actuator can be expected as a sensor and/or a controller of hydrogen gas flux in various hydrogen-related devices. This significantly improved mechanical response was attributed to the switching of the reactions in the rate determining steps.
In order to evaluate influence of electron beam (EB) irradiation on elasticity and stress- strain curve of composite materials reinforced by carbon fiber (CF), carbon fiber reinforced polymer (CFRP) and carbon fiber reinforced graphite (C/C) were treated by EB irradiation of 0.3 MGy. Since the EB strengthening was mainly dominated by the ductility enhancements of carbon fiber and matrix of epoxy resin, EB irradiation enlarged fracture stress and enhanced fracture strain of CFRP. Furthermore, EB irradiation slightly enhanced bending elasticity of CFRP and largely enhanced the initial spring constant related to elasticity of C/C coil. Although the elasticity enhancement of carbon fibers did not largely contribute that of CFRP, that of treated graphite matrix in C/C mainly caused the C/C coil elasticity enhancement by EB irradiation. Such a new treatment is a dream-worthy technology for structural materials to be applied in the fields of future engineering.
To develop an optical scanning device, the magnetostrictive alloy thin films were prepared on silicon wafer and polyimide substrate by d.c. magnetoron sputtering process. The TbFe1.8 film shows a giant positive magnetostriction of about 1200 ppm at 5 kOe, whereas the SmFe2.5 shows a giant negative magnetostriction of about 1200 ppm. The magnetostrictive alloy thin films device showed reproducibility below 5 kOe of magnetic field.
To protect space structures from debris impact, the new types of shield using a self-sealing materials are suggested. A hole by debris impact on shield will be fixed with the self-sealing materials by melting, sealing and solidification. Time to seal impact hole was experimentally simulated. If time to seal impact hole was assumed to be about 5 s, viscosity of self-sealing materials should be about 0.5 Pa s. In addition, glasses with supercooled liquids at elevated temperatures were also suggested as candidate materials for sealing, because low values of viscosity were obtained below melting points. From these results, boride ceramics, high temperature polymer materials including a liquid-crystal and light metallic glasses were suggested as the candidate materials for the self-sealing system.
This paper describes recent developments of moving materials operated by changes in temperature, hydrogen gas pressure and magnetic field. In order to obtain moving functions with high irradiation resistance for metallic glass, high transparency for high heat resistant glassy ceramics and extremely large motion for lightweight polymer, unimorph structural device driven by glass transition have been developed. To get high responsiveness operated by magnetic field, new movable devices of unimorph magnetostrictive alloy films were developed. High susceptibility with high resistance to noise was also found for the giant magnetostrictive Fe-Pd stainless alloy. To obtain high power, a movable unimorph devise of hydrogen storage LaNi5 film deposited on substrate was developed. In order to get large motion, unimorph structural composite sheets constructed by the silicon polymer with and without hydrogen storage LaNi5 fine powder dispersion.
A variable reluctance hybrid magnet has been developed to apply new type of high torque motors. A permanent magnet, electromagnet and yoke construct the variable reluctance hybrid magnet. From an engineering point of view, it is important to know the magnetic field around a variable reluctance hybrid magnet. Based on the results of magnetic flux density measurement around the hybrid variable reluctance magnet, the high magnetic flux density was found at edges and joints. The high magnetic flux density was also obtained with electrical current of 10 A at optimum setting form. Therefore, we concluded that the strong force of rotor of the hybrid motor was generated by high surface flux density of the hybrid magnet.
New high responsive Fe-Pd magnetostrictive films with high power were developed and prepared by magnetron sputtering. The in-plane magnetization of Fe-Pd thin film was larger than that of the Tb0.3Dy0.7Fe2 alloy film. The Fe-Pd magnetostrictive films show large magnetostriction and high magnetostrictive susceptibility at low magnetic field from earth magnetic field to 1 kOe. The high magnetostrictive susceptibility of the Fe-Pd alloy films obtained was appropriate as a remote actuator in low magnetic field. If an ideal Fe-Pd magnetostrictive films are developed to apply the micro-machine, offering the advantages of low cost, lightweight and relatively simple design. In order to
apply these properties to a practical actuator, load dependence of magnetostrictive susceptibility was serious potential problems. In this study, the magnetostrictive susceptibility changes were measured under different loading stresses. As a result, Fe-Pd alloy film showed high magnetostrictive susceptibility under high film loading stress above 50 MPa.
Effects of EB irradiation on fracture toughness were studied for soda lime glass and glass fiber. The EB irradiation improved the hardness, ductility, fracture stress and fracture toughness. The fracture stress was 1.43 GPa for the glass fiber before EB treatment. The irradiation enhanced the fracture stress. The fracture stress at Pf=0.5 was 1.89 GPa for glass fiber samples treated by 65 Mrad-irradiation. It was approximately 0.46 GPa larger than that before EB treatment. Based on ESR results, the reinforcement can be explained. The changes in fracture stress were in good agreement with the density change in dangling bonds, because a high tensile glass fiber was obtained at 65 Mrad-irradiation. Thus, we confirmed that the glassy cluster structure with high dangling bond density was obtained in high tensile glass fibers prepared by 65 Mrad-irradiation. The EB irradiation controlled the fracture toughness of glasses. To confirm the mechanism, an alpha-aluminum oxide crystal sheet was also studied.
Two kinds of high power actuator film materials prepared by PVD process were developed. One is the The Fe-Pd alloy film, which shows large magnetostriction and high magnetostrictive susceptibility at low magnetic field from earth magnetic field to 1 kOe. Another is the hydrogen storage La-Ni alloy film on a polyimide substrate, which was prepared using a flash evaporation method. The hydrogen storage alloy film showed the reversible shape change, which operated by hydrogen absorption and desorptions. This bi-material actuator was driven by the large volume expansion of hydrogen storage La-Ni alloy film. In this study, the strain changes were measured under different loading stresses. The powers of these two actuator materials were larger than that of Ni-Ti alloy commercially used.
Three types of magnetic field operated shape memory ceramics have been developed. Namely, the shape memory movements can be operated by changes in magnetic flux density. The reversible shape memory effects are often induced by magnetostriction and magnetic field induced twin formation for Fe-Pd alloys. The former shows the precise shape change, whereas the later shows the large shape change expected. The strain value was about 182 ppm at 0.3 kOe at room temperature. The high magnetostrictive susceptibility was detected at low magnetic field. It was higher than that of Tb0.3Dy0.7Fe2 thin film developed. The other magnetic field operated shape change is recently found on softening near critical temperature of superconductors. The softening induced shape memory effect (SSME) has been found from 9.5 K to 20 K in pure metallic niobium.
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