Advanced Materials Research Vols. 47-50

Abstract: A novel nanocomposite based on nanodiamond (ND) powder and Poly (lactic acid) (PLA) for potential bio-engineered applications was fabricated for the first time by using melting compound methods. Its structure and mechanical properties were investigated by using transmission electron microscopy (TEM), scanning electron microscopy (SEM) and tensile property test. The results showed that as compared with pure PLA, ND/PLA nanocomposites possessed higher modulus, higher strength and comparable elongation at break, in other words, the mechanical properties of PLA were significantly improved by incorporating ND powder into it. This is presumably due to homogeneous dispersion of ND cluster, good interfacial bonding and unique ND bridge structures in the ND/PLA nanocomposites.

Abstract: A new biocomposite based on chicken feather fiber (CFF) and Poly (lactic acid) (PLA) was fabricated for the first time by melting compound methods. Its mechanical properties and fracture surfaces were investigated by using tensile tests and scanning electron microscopy (SEM), respectively. The results showed that the tensile modulus and elongation at break of PLA samples were improved by adding a small amount of CFF. The elongation at break of a CFF/PLA sample with 2 wt% of CFF was 56% higher than that of pure PLA. This may ascribe to the good adhesion and interactions between the CFF and PLA matrix.

Abstract: The plate silencer1 which consists of an expansion chamber with two side branch cavities covered by a light panel can achieve a desirable noise reduction in broadband theoretically. The concept is similar to drum silencer2. To attain optimal noise reduction, either the membrane should be of minimal weight while retaining very high tension or the panel should be kept with very high bending stiffness that is dependent on its geometry and mechanical properties. To achieve such goal, various kinds of composite system such as carbon fibers or aluminum were mounted on light core foam. A design of the composite panel which can provide a reduction in panel weight as well as enhance the bending stiffness, is introduced in this project. Predictions of the new model are to be compared with the normal foam plate in the aspects of noise reflection capability and performance of noise abatement apart from the material properties.

Abstract: A high-strain optical fiber sensor system has been developed to provide a cost-effective solution for measurement of very large strain. The measurement of large strain in the order of a few tens of % strain (up to 40 % strain) in geotextile materials has been achieved using an extrinsic plastic optical fiber sensor (POF). Based on this design, the sensor is not limited to operating within the elastic region of the plastic fiber proposed by other workers in the field. The present design allows for compression strains to be measured even after exceeding strain levels of 5% (typical plastic strain values of POFs based on fiber stretching.) The POF were initially calibrated using a linear variable displacement transducer and the results based on tensile tests of a series of geotextile fabrics have shown to compare well with other reference measurements.

Abstract: Artificial polycarbonate moth eye structured plate was used to emboss the moth eye nano-pattern into PVC films. Embossing was done at 100°C to prevent any damage on polycarbonate template. With embossing of moth eye nano-patterns, transmittance of PVC film was increased up to 6% over 400nm to 800nm wavelength region. This embossed PVC film was then used as an imprint template after depositing thin layer of SiO2 and self-assembled monolayer. Consequently, polymer based moth eye nano-patterns were formed on glass template after UV imprinting and its transmittance was increased from 90% to 92%.

Abstract: PPO was a better intensifier and charred material for High-impact polystyrene (HIPS), it could make HIPS achieve UL94V-0 with APP, MC, RDP. Especially, RDP not only improved the flame-retarded property but also controlled the hole producing, and had the best consistent with matrix which could improve the mechanical properties. SBS and SEBS were better consistent with matrix, especially SEBS was tiny granule, which could be dispersed in matrix easily. The properties of SEBS toughened the non-halogen flame-retarded HIPS was followed: tensile strength: 18.83MPa; izod notch impact strength: 15.7kJ/m2; UL94V-0.

Abstract: Since the atomic structure of carbon nanotubes demonstrates evidently anisotropic mechanical properties an analytical molecular structural mechanics model is introduced in order to derive longitudinal and circumferential moduli of nanotubes. The identification is based on the eigenfrequencies analysis of the proposed computational model. It is combined with the FE analysis and the interatomic potentials. Detailed derivations are presented and the predicted results are shown and discussed with a few computational examples.

Abstract: Usually magnetorheological fluids are dispersions of micronic magnetic particles in a carrier liquid. We shall present the basic phenomena related to the numerical description of homogenization for such type of composite structures. Our attention is mainly focused on the prediction of the effective permeabilities that can play a fundamental role in the aggregation of magnetic particles and are responsible for the gelation of the suspension and will allow the suspension to flow. We shall also give some information on the optimal design of the effective permeabilities taking into account the shape of magnetic particles.

Abstract: A new optimization problem for laminated multilayered structures having surface bounded piezoelectric patches have been formulated and solved. The present formulation introduces boundaries of piezoelectric patches as new class of design variables. In addition classical design variables in the form of ply orientation angles of orthotropic layers are also taken into account. The design objective is the minimization of normal maximal deflections. The standard Rayleigh-Ritz method is used, however, the accuracy of optimal design are verified with the aid of the FE package ABAQUS. Examples are presented to illustrate the performance of the proposed model.