Resin Matrix／Fiber Reinforced Composite Material, Ⅱ： Method of Solution and Computer Code

According to a mathematical model which describes the curing process of composites constructed from continuous fiber-reinforced, thermosetting resin matrix prepreg materials, and the consolidation of the comopsites, the solution method to the model is made and a computer code is developed, which for flat-plate composites cured by a specified cure cycle, provides the variation of tenaperature distribution, the cure reaction process in the resin, the resin flow and fibers stress inside the composite, the void variation and the residual stress distribution.     

Resin Matrix／Fiber Reinforced Composite Material,Ⅲ ： Simulating Results

According to the mathematical model which describes the curing process of composites constructed from continuous fiber-reinforced, thermosetting resin matrix prepreg materials, and the consolidation of the composite, the computer code calculates the data of the process variables of the flat-plate composites cured by a specified cure cycle, provides the variation of temperature distribution, the cure degree process, the resin variation and fibers stress inside the composite, the void variation and the residual stress distribution. The mechanism of curing process is illustrated and the cure cycle of composite material is optimized.     

Rapid Tooling Technique Based on Stereolithograph Prototype

Rapid tooling technique based on the sterelithograph prototype is investigated. The epoxy tooling technological process was elucidated. It is analyzed in detail that the epoxy resin formula is easy to cast, curing process, and release agents. The transitional plaster model is also proposed. The mold to encrust mutual-inductors with epoxy and mold to inject plastic soapboxes was made with the technique. The tooling needs very little time and cost, for the process is only to achieve the nice replica of the prototype. It is benefit for the trial and small batch of production.     

Design Optimization of RFI Parameters by Manufacturing T-shaped Composite Panel

The aim of this project is to develop a novel approach for optimizing design resin film infusion (RFI) processing parameters by manufacturing T-shaped composite panel. The dimensional accuracy was selected as the objective function. By investigating the rheological properties of resin film, the compaction behavior of fiber preform and characteristics of RFI process, an optimal mathematical model was established, it was found that the numerical results obtained from the RFICOMP program package have good consistency with the experimental results, and this optimization procedure can be applied to other composites manufacture processes.?AKeywords：Composites, Resin Film Infusion, Design Optimization, Accuracy.     

Monte-Carlo Simulation on the Failure of Fiber in a Single Filament Composite

A Monte-Carlo method is used to simulate gradual fracture of fiber in a single filament composite with the increase of virtual stress. A simple computational algorithm is developed to judge where breaking point will happen in the composite and a probability model based on Weibull-distribution is designed to calculate the average fragment length by producing stable and uniform random number in (0,1) . Compared to the published experiment results, the simulating average fragment length is quite perfect.     

Study on Quality Evaluation Model in Multi-station Assembly Processes

Based on features of dimension variation propagation in multi-station assembly processes, a new quality evaluation model of assembly processes is established. Firstly, the error source of multi-station assembly system is analyzed, the relationship of dimension variation propagation in multi-station assembly processes is studied and the state equation for variation propagation is constructed too. Then, the feature parameters which influence variation propagation and accumulation in multi-station assembly processes are found to evaluate quality characteristic of the assembly system. Through the derivation of equation on dimension variation propagation, station coefficient matrices which are combined and conversed to determine the max eigenvalue are educed. The max eigenvalue is multiplied by the weight coefficient to establish the quality evaluation model in multi-station assembly processes. Furthermore, assembly variation indexes are proposed to judge of the assembly technology process. Finally, through the practical example, the application of the model and assembly variation indexes are presented.     

GENERAL COMPUTER MODEL FOR SHEET METAL DEEP-DRAWING PROCESS

A new comprehensive computer model was developed for sheet metal deep-drawing process, based on the theory of plastic anisotropy and under consideration of the effects of bending, blank-holding force, strain-hardening, the variation of thickness and tooling geometry. The model could be used to simulate the deforming stages of deep-drawing process and get the continuous distributions of stress and strain from the radial drawing region of material over a die and the stretch-forming region of material over a punch. It is concluded that the total strain theory can be used as a substitute for the incremental strain theory to analyse the force and deformation in sheet metal deep-drawing process. In addition, the effect of bending was also obtained.     

Modeling of a Schottky Diode in CMOS Process with a Flexible “Open-Through” On-Chip De-embedding Method

Modeling of Schottky diodes in the CMOS process is a key step in ultra-high frequency(UHF) radio frequency identification(RFID) transponder designs.Accurate Schottky diode models need both DC and RF models.Conventional DC models of the Schottky diode fail to predict the forward leakage current,which is crucial for precise simulation results.This paper presents a Schottky diode model with an additional diode which gives the correct forward leakage current.The RF model of the Schottky diode is constructed based on the measured S-parameters.Then,an on-chip de-embedding process is needed to remove the parasitics due to the pads and interconnection lines in the S-parameter test.A flexible "open-through" on-chip de-embedding method is proposed which only requires an "open" dummy and a "through" dummy,with all the lumped and distributed parasitics equivalent to two-port networks to give sufficient high-frequency de-embedding accuracy.By the help of this de-embedding method and the new DC model,the accuracy of the established diode model could be guaranteed.The Schottky diode model is verified by comparison between measurements and simulations and successfully applied to an RFID transponder design.     

Effect of Sedimentation on the Microwave Permeability of FeSiAl Composites

In order to achieve an easy fabrication and considerable directional orientation, we use a sedimentation method to prepare composites consisting of Fe Si Al flakes. The flakes are dispersed in hydroxylated acrylic resin solution in sonication and natural form into laminated composite samples. Then, the toroidal rings are made with the prepared laminated composite samples. Compared with random orientational Fe Si Al flakes in the composite, the complex permeability of laminated sample has been obviously improved when microwave frequency is below 4 GHz, especially for the imaginary part. A model is proposed to explain the formation reason of aligned Fe Si Al composite by this method. Damping factor(α) is calculated by the combination of the effective medium theory and Landau-Lifshitz-Gilbert equation, and the permeability of the samples is verified by these theories.     

Acoustic band gaps of two-dimensional three-component composite

Numerical analyses of the band-gaps in the two-dimensional three-component periodic composite are presented in this paper. The three-component composite is composed of an array of coated cylinders embedded in a resin. The coated cylinder consists of a hard inner core and a soft coating, which has much smaller wave velocity and mass density than the matrix and the inner material. The calculated band gaps appear in a lower frequency domain in contrast to the two-component counterpart composite because of the localized resonance in the elastically soft coating ring. The influence of the properties of the different coating materials and the geometry of the crystal on the band gaps is also investigated.     

Integration of CAD／CAE System for Casting Process Design

Concurrent engineering is needed to modernize the foundry industry and to reduce the scrap from castings and thus increase the economic profit. This paper presents an integrated 3-D CAD/CAE system for a foundry using concurrent engineering which considers casting structure, casting type, and manufacturing properties in the CAD module to design the pouring system, the riser, the chill core and so on. A visualized solid model is developed for the casting component with the model design enhanced by CAE analysis. Heat transfer and fluid flow simulation are used to analyze the initial design. The whole product development process is analyzed using concurrent engineering methods. The application shows that the integrated system can improve the efficiency of the design and manufacturing process of die casting.     

Prediction of Final Velocity of Aramid Fabric-Resin Composite Laminates Subjected to Ballistic Impact

The strain rate effects of aramid fiber material, quasi-static and ballistic impact perforation of composite laminates made of aramid fabric and phenolic resin/PVB are investigated respectively by means of MTS, split Hopkinson tension bars and ballistic impact apparatus. The tensile impact experiments on aramid fiber material are performed in strain rate range from 0.01/s to 1000/s. Experimental results show that the mechanical properties of aramid fiber material are insensitive to strain rate in the range from 0. 01/s to 1 000/s. An energy model to predict final velocity of composite laminates subjected to ballistic impact is proposed on the basis of experimental data of quasi-static perforation through the targets. The predicted final velocities show good agreement with the experimental final velocity.     

Insect population differentiation in response to enviromental thermal stress

Numerous studies reported the adaptation strategies adopted by ecthotherms to survive under environmental thermal stress. Geographic and seasonal variations in the thermal stress tolerance, which is closely associated with species' climatic adaptation and allopatric speciation, have been extensively investigated in insects. The variation patterns suggest directional selection for species' adaptive straits, and are used to predict the origin, distribution and dynamics of insect populations. These studies are becoming more and more important in the context of global warming. This paper discusses the process of adaptation to environmental thermal stress and the mechanisms underlying the differentiation in related adaptive straits of insect populations.     

ANISOTROPY OF THE KERATIN FIBRE COMPOSITE

This paper presents a composite model of the natural keratin fibres (wool and hair) whichconsists essentially of isotropic viscoelastic filaments, oriented parallel to each other in the fibreaxial direction, embedded in an isotropic viscoelastic matrix. The model accurately fits the exper-imental data on the fibre axial stress relaxation moduli and provides upper and lower bounds forthe initial/final values for the fibre transverse tensile and shear stress relaxation moduli andtransverse Poisson's ratio. The partially water penertrable filament phase of the composite modelis identified as the microfibrils in the fine structure of keratin. The strong anisotropy of keratinsin mechanical properties and hygral/thermal expansion is analyzed in terms of composite struc-ture and mechanical as well as the thermal/hygral properties of the two constituent phases.     

An integrative estimation model of summer rainfall-band patterns in China

Three variation indices are defined to objectively and quantitatively represent fluctuations of three rainfall-band patterns in summers in China for the period from 1951 to 2005, and the variation features of these indices are analyzed on both of interdecadal and interannual scales. A new method is proposed to establish an integrative estimation model based on the analysis of rainfall-band indices, and the model is applied to air, ocean factors to estimate their roles on variations of three rainfall-band patterns on different time-scales. The tests of estimation effects show that the fluctuations of three rainfall-band patterns are composed of variations on both significant inter-decadal and interannual scales, of which the interannual variation is mainly influenced by the Elnino/Lanina events, the East Asia monsoon and the ridge locations of subtropical high pressures in western pacific, while the interdecadal variation is mainly controlled by the Pacific decadal oscillation and interdecadal oscillations of the Arctic oscillation, ENSO, Nino3 sea surface temperature and summer monsoon. The estimated results from the integrative estimation model of rainfall-band patterns suggest that the way of estimation first according to each time scale of both the interdecadal and interannual scales, then estimating with an integration, which is proposed in this paper, has an obvious improvement on that without separation of time scales.     

An integrative estimation model of summer rainfall-band patterns in China

Three variation indices are defined to objectively and quantitatively represent fluctuations of three rainfall-band patterns in summers in China for the period from 1951 to 2005, and the variation features of these indices are analyzed on both of interdecadal and interannual scales. A new method is proposed to establish an integrative estimation model based on the analysis of rainfall-band indices, and the model is applied to air, ocean factors to estimate their roles on variations of three rainfall-band patterns on different time-scales. The tests of estimation effects show that the fluctuations of three rainfall-band patterns are composed of variations on both significant inter-decadal and interannual scales, of which the interannual variation is mainly influenced by the Elnino/Lanina events, the East Asia monsoon and the ridge locations of subtropical high pressures in western pacific, while the interdecadal variation is mainly controlled by the Pacific decadal oscillation and interdecadal oscillations of the Arctic oscillation, ENSO, Nino3 sea surface temperature and summer monsoon. The estimated results from the integrative estimation model of rainfall-band patterns suggest that the way of estimation first according to each time scale of both the interdecadal and interannual scales, then estimating with an integration, which is proposed in this paper, has an obvious improvement on that without separation of time scales.     

The Deoxidation Process of GCr15 Steel

It is shown that the average [O] in the steel can be decreased to 12.86 ppm and there is an optimal [%Si] at the end of melting as 0.11%, at which [O] after vacuum carbon deoxidation (VCD) is minimum. A kinetical model has been deduced to simulate the VCD process. The results show that adding Si before Al is superior to the adding Al before Si with respect to the final [O] in the steel. It is suggested that the melting point of covering slag should be lower than 1550℃, and (FeO+MnO) should be less than 1%, so as to effectively refine GCr15 steel.     

Probing the microenvironment of an oligo-（p-phenylene vinylene） derivative encapsulated in polymer-impregnated sol-gel silica matrix

Polymer-impregnated silica sol-gel composite materials are hosts for organics in advanced optics application. An oligo-phenylene vinylene derivative 4,4‘-(1,4-phenylene dithenylene)-bis-(N-methyl pyridinium iodide) (OPVD) was introduced to poly(hydroxyethyl methacrylate) (PHEMA)-impregnated silica composite film by the sol-gel process. By comparing the X-ray diffraction, UV-visible spectra, steady-state and time-resolved fluorescence spectra of OPVD in three solid matrices (PHEMA/silica composite film, pure PHEMA film, and pure silica film), the similar results of PHEMA/silica composite film and pure PHEMA film demonstrate that the OPVD is primarily surrounded by a PHEMA-like environment in the composite matrix. The model of such structure is presented, which is useful for further understanding and optimizing of properties of doped sol-gel materials.     

Research on Stress Testing of OSPF Protocol Implementation

The stability and robustness of routing protocol implementations (RPI) in a router are becoming more and more important with the growth of Internet scale. A novel approach named stress testing is proposed to test the properties of RPI. Compared with some traditional test techniques, stress testing is remarkably necessary to inspect and analyze RPI. The test environment is proposed and the test process of OSPF RPI is illustrated by a stochastic Petri Net model with large-scale route simulation and OSPF protocol emulation. Based on this model, the integrated performance tester (IP-TEST) is designed and developed, with which we test a CISCO2600 router. With mathematical methods, we find that the computational complexity of OSPF implementation in this router is O (lnN)^4)to the number of its routing table entries. This experiment shows that this technique can inspect the stability, the computational complexity and the sealability of RPI. Furthermore, it can also be widely used with other routing protocols, such as RIP and BGP.