The new structures and multifunctional materials is that it can achieve some other special functions while it has ability to
carry, such as wave-transparent, absorbing, anti-lightning, anti-heat, anti-nuclear etc. It represents the direction of future
development of structural materials. And graphene is the one of two-dimensional atomic crystal free substance only
found in the existence and shows great importance for fundamental studies and technological applications due to its
unique structure and a wide range of unusual properties. It exhibits great promise for potential applications in chemistry,
materials, and many other technological fields.
In this paper, we prepare nanopaper through physical vapor deposition (PVD) with a variety in the weight ratio between
graphene and nanofiber. Then prepare composite materials with nanopaper and T300/AG80 prepreg by the meaning of
autoclave molding. The morphology of nanopaper was characterized by transmission electron microscopy (TEM) and
scanning electron microscope (SEM). And the electrical properties and the EMI shielding performances of these
nanocomposites have been investigated experimentally by and four-point probe measurement and vector network
analyzer. The experimental results indicate that the composites made from graphene and nanofiber nanopaper have
highly electric capability, and the EMI shielding value of composites were all up to -15dB. In the same time the
conductivity and the EMI shielding performances were improved with increasing the ratio of graphene in nanopaper.
We tested the mechanical properties of composite materials at the same time. The average strength of composite
materials is about 2000MPa, the elastic modulus is 130GPa above. We are sure that it can be used as the load-bearing
structural material which has a multi-functional performance in the aviation field.
We have previously reported a novel Fiber Optic Acoustic Emission Sensor (FOAES), which was
specially processed based on fused-tapered optical fiber coupler. The FOAES was packed with silica
capillary tube so that it could be embedded in damage monitoring of composite materials. But the linear
damage location of acoustic emission using double sensors had not been tried. In this paper, linear
damage location experiments with double sensors were tested on aluminium plate and composite plate.
The test results showed that linear damage position was identified within ±6.25 mm on aluminium plate
and ±4.84 mm on composite plate.
A fiber optic acoustic emission sensor based on fused-tapered coupler and its applications in structural health monitoring
are proposed in this paper. The sensor was embedded into the Carbon Fiber Reinforced Polymer (CFRP) laminates and
tested using pencil lead break tests compared with the commercial acoustic emission sensor (R15 PZT). It successfully
detected the AE signals. FOAES was applied in the Structural Health Monitoring (SHM) of CFRP materials. Failures of
carbon fiber/epoxy composite laminates during three-point- bending test were monitored embedded FOAES. Results
identified that the sensor embedded into composite structures successfully monitored failures of composite laminates online.
In this paper, a variable camber wing, which comprises a flexible skin, a metal sheet, and a honeycomb structure, is
presented. Shape memory polymer (SMP) is selected for the use of flexible skins. Embedded heating wire springs act as
the activation system for the SMP. Experimental result shows that the inherent separation does not occur between the
heating elements and SMP upon elongation because of elasticity of wire springs. The deformation of SMP skins at
different temperature conditions is analyzed in order to establish the relationship between the deformation of the skin and
pre-strain applied in the SMP skin. Fibre Bragg Grating (FBG) sensors, with flexibility and small size, are bonded on the
surface of the metal sheet to measure the deflection on the some certain points. The relation of the strain on the upper
surface of metal sheet and the deflection of the trailing-edge is established to ensure the position of the bonded FBG
sensors. The curve shape of the bending metal sheet can be reconstructed using the calibration information.
This paper introduces a novel multifunctional fiber sensor with two FBGs (measuring temperature and strain
simultaneously) and a fiber optic coupler (monitoring the damage of composite) for structural health monitoring. Two
FBGs with different wavelengths are abreast connected to an optical splitter: One is capsulated in glass capillary tube to
measure temperature and not affected by strain, the other one is to measure temperature and strain. The other port of the
former FBG is connected to the fiber optic coupler, using the transmission intensity in grating for structural health
monitoring (SHM) of composite materials.
It is pivotal to discriminate the variable of it caused by temperature and strain, as the wavelength of FBG varies with
temperature and strain simultaneously. The technique is designed for distinguishing strain and temperature to solve the
cross sensitivity problem in this paper. A series experiments demonstrate that the novel multifunctional optical fiber
sensor possesses high sensitivity and high precision. With composite materials being used widely in aerospace
engineering, national defence, civil engineering, oil field and etc, monitoring the damage of them is more important
regarded. The temperature and strain affect the damage of composite materials mostly. Combined with the AE events,
according to the temperature and strain of composite materials, the sensor can confirm whether they are demolished and
how intensity they are damaged.
A novel pressure sensor based on FBG is designed in this paper. Not only in normal environment, also does it accurately
work in water and petrol where other conventional sensors can not work normally. In this paper, the principle of the
novel sensor is introduced, and two experiments are further performed: One is keeping the sensor flatly in the gastight
silo whose pressure is supplied by an air compressing engine, and the other one is keeping the sensor in liquid. The
analysis of the result data demonstrates that the sensor possesses high sensitivity, high linearity, high precision and
repeatability. Its experimental linearity and sensitivity approach 0.99858 and 5.35×10-3MPa-1, respectively. It is also
discussed using the sensor to measure the volume in tank.