Applied Mechanics and Materials Vols. 644-650

Abstract: Spectra of 27 steel samples were acquired by Laser-Induced Breakdown Spectroscopy (LIBS) for steel classification. Two methods were used to reduce dimensions: the first is to select characteristic lines of elements contained in the samples manually and the second is to do principal component analysis (PCA) of original spectra. Then the data after reducing dimensions was used as the input of artificial neural networks (ANN) to classify steel samples. The results show that, the better result can be achieved by selecting peak lines manually, but this solution needs much priori knowledge and wastes much time. The principal components (PCs) of original spectra were utilized as the input of artificial neural networks can also attain a good result nevertheless and this method can be developed into an automatic solution without any priori knowledge.

Abstract: In this paper, the low-velocity performance of stiffened composite panels is investigated experimentally and numerically. In order to illustrate the effect of the stiffener, a number of plain laminates with same lay-up of the skin were impacted in various energies. Progressive damage models based on continuum damage mechanics (CDM) were used in combination with cohesive interface elements to predict the structural response and fracture mechanics of stiffened composite panels. The constitutive mode was implemented into the ABAQUS/Explicit FE code by user-defined material subroutines (VUMAT). The developed FE model made a good prediction about the structural impact response of stiffened panels over the rang of impact energies examined. Very good agreement was achieved between the extent of damage predicted around the impact site and the damage detected by non-destructive technique (NDT) ultrasonic C-scan of the panels.

Abstract: Expanded graphite is used as framework material in inorganic or organic heat storage materials commonly, of which the function is to improve thermal performance of the relevant materials. However, its negative effect is unclear. In this paper, the change of endothermic temperature of chemical heat storage material Ca_xZn_y(OH)_2(x+y) by graphite addition is reported. Differential scanning calorimetry (DSC) is employed to perform the measurement. The result shows that the initial temperature and width of the endothermic peak decrease due to the action of the added graphite slightly; Along with the increase of graphite content, the endothermic peak moves to lower temperature further, the width and height of the peak reduce simultaneously.

Abstract: This article uses the cast-penetrated-heat treatment process produce V₈C₇ particle on the surface of iron base composite material, and analyze its organizing appearance using methods such as XRD, SEM, measured its hardness with micro hardness tester of type TUKON2100, operate wear test under different load with wear test machine of ML-100. Results show that the surface of the particle reinforced iron matrix V₈C₇ composite sample maximum microhardness is 2333 HV_0.05. At room temperature, when the load is 15N, its average abrasive resistance is about 13 times that of it of grey cast iron, which improves the wear resistance of the iron substrate to a great extent.

Abstract: Miscanthus is a high yielding bioenergy crop. In this study, we selected four typical pairs of Miscanthus samples which presents different cell wall compositions. After different concentration pretreatment of NaOH (0.5%, 1.0%, 4.0%), four species shows significant difference in saccharine production. Much more xylose was extracted in the supernatant solution; the average glucose yield of all samples was about 2.0% in the concentration of 4.0%, which while the xylose yield was 12.0%. Direct enzymatic hydrolysis of the NaOH presoaked biomass was found to give higher glucose yields of 11–26%, and low xylose yields of 11–15%.Lower concentration of NaOH resulted in distinct differences in both glucose and xylose hydrolysis yields.

Abstract: aluminum and aluminum alloy can be squeezed as Leal sealing body measurement instrument. Aluminum alloy has the advantages of high strength, corrosion resistance and high temperature, traceability, rich surface information, Leal sealing has good anti-counterfeiting and anti-pry.

Abstract: Surface treatment was carried out on the welded cruciform joint of P355NL1 steel by using the HJ-II-type ultrasonic impact machine. The ultrasonic impact current is 1.5A, the impact amplitude is 20 microns and ultrasonic impacting time is 5min. Tensile test was carried out for both treated specimen and un-treated specimen. The fracture observed with the scanning electron microscope of 6360LA type. The experimental results show that although the compressive residual stress can be obtained in the surface of weld toe area, and the grain size in the surface of welded cruciform joint can be refined, but the mechanical property of the welded cruciform joint of P355NL1 steel can not be improved through the ultrasonic impact treatment. The main reason is that the ultrasonic impact layer is only 70um, it is to thin to compared to the thickness of the specimen.

Abstract: Surface treatment was carried out on the butt joint weldment of P355NL1 steel by using the HJ-II-type ultrasonic impact machine. The ultrasonic impact current is 1.5A, the impact amplitude is 20 microns and ultrasonic impacting time is 5min. Tensile test was carried out for both treated specimen and un-treated specimen. The fracture observed with the scanning electron microscope of 6360LA type. The experimental results show that although the compressive residual stress can be obtained in the surface of weld toe area, and the grain size in the welded joint can be refined, but the mechanical property of the butt joint of P355NL1 steel can not be improved through the ultrasonic impact treatment. The main reason is that the ultrasonic impact layer is only 120um, it is to thin to compared to the thickness of the specimen.

Abstract: To exploit a bioactive material as components of functional products, juices from purple perilla; purple potato and blueberry were abstracted and concentrated. These concentrated juices were diluted to optimize the composition by evalustion of lavor. A bioactive material with 30% concentrated juice from purple perilla,50% from blueberry and 20% from purple potato, which contains 3.72% anthocyanin and shows antioxidant activity. This biomaterial can be use in processing functional products which have the functions of plant anthocyanin.

Abstract: Graphene nanoplatelets (GNP) and thermoplastic polyurethane (TPU) have been often used as filler and matrix, respectively, to produce composites. In this work, TPU/GNP composites were prepared via a melt blending method. The mechanical properties and frictional properties of TPU/GNP composites were investigated. Because the GNP is very expensive, we investigated to use graphite as the filler, to use PP-g-MAH as the compatibilizer and examined the characteristics of the prepared composites. Frictional properties and mechanical properties of GNP/TPU composites remarkably improve when adding PP-g-MAH as the compatibilizer. Tensile strength of composite containing 10wt % of GNP and 10wt% PP-g-MAH was measured as 25.5MPa. When the graphite was used to replace for GNP, the frictional properties of composites decreased, but the mechanical properties improved.