A Review of Fiber-Reinforced Injection Molding: Flow Kinematics and Particle Orientation

The existing flow and particle orientation models applicable to fiber- reinforced injection molding are reviewed. After a brief description of injection molding, previous studies on the flow kinematics and fiber reinforcement are presented. Basics of Hele-Shaw flows are described Including the commonly used viscosity models and foun tain flow effects. Some of the existing models for particle orientation are analyzed with particular emphasis on the amsotropic description of the material system. Concentration regions for short fiber suspensions are defined and relevant constitutive equations are dis cussed. A few example solutions are also given which describe the three-dimensional ori entation field for the filling of a sudden expansion cavity, depicting skin-core orientation structure.Yeshttps://us.sagepub.com/en-us/nam/manuscript-submission-guideline

Detection Limit of ultra-scaled Nanowire Biosensors

Abstract-The fundamental detection limit of ultra-scaled Si nanowire FET (NWT) biosensors is studied with a NEGF quantum microscopic approach. For negatively charged analytes, a N-doped NWT is found to be more sensitive and to get less sensitivity degradation when increasing channel length. Our results predict threshold voltage shifts due to a single charge analyte on the order of tens to hundreds of mV in dry (air) or low ionic solution environments, which hint at single charge/analyte detection. However, the sensitivity to a single charge analyte rapidly drops down to the mV range in typical ionic solution and SAM conditions

Non-isothermal simulation of the resin transfer moulding process

The resin transfer moulding (RTM) of thin components is investigated by means of numerical simulation. The effect of mechanical dispersion in the gapwise direction is taken into account in the energy and species balances, while no mixing is considered along the midsurface. In a first model, incomplete mixing is considered in the gap, while perfect mixing is assumed in a second model. Several examples are analysed, which highlight the effect of mechanical dispersion on the general heat transfer. (C) 1997 Elsevier Science Limited

Prediction of thermo-mechanical properties for compression moulded composites

We present a method to determine the thermo-mechanical properties of compression moulded composite parts. The flow-induced fibre orientation is first calculated by numerical simulation, and the resulting orientation state is used as input in a micromechanical model that predicts the thermo-mechanical properties of the part. A two-step homogenization scheme based on the grain model approach is followed. First, the properties of a reference composite with aligned fibres are estimated by means of a mixture rule between the upper and lower Hashin-Shtrikman bounds (derived by Willis). This method is in agreement with the Mori-Tanaka estimates for moderate concentrations, and gives better results for higher concentrations. Next, the properties of the composite are obtained by averaging several reference composites with different fibre directions. An example of a 3-D compression moulded composite part is analyzed and the results are discussed. (C) 1997 Elsevier Science Limited