Mold Filling Analysis in Vacuum Infusion Molding Process Based on a High-Permeable Medium

The objective of this paper is to understand the flow mechanism through visualization experiments and discuss theinfluence of process parameters on mold filling process. A 2D leakage flow model is developed to simulate the moldingprocess, and the simulation results show good agreement with experiments.

Vacuum Infusion Molding Process Part 1:VIMP Based on a High-Permeable Medium

The visualization experiments were carried out to investigate the permeability of the high permeable medium (HPM) and the roles of the peel ply and the HPM in the mold filling.The influence of process parameters on mold filling is discussed.Furthermore,the whole vacuum infusion molding process (VIMP) procedure is introduced in detail taking the manufacture of a model boat for example.

Vacuum Infusion Molding Process (Part 2 VIMP Based on Grooves)

The optimal parameters for flow grooves and supply grooves were determined by a series of experiments,and the influences of various molding conditions on the mold filling process were analyzed.Furthermore,the whole VIMP procedure based on grooves was introduced in detail taking the manufacture of a sandwich panel as an example.

Rheological Behaviors and Processing Windows of Low Viscosity Epoxy Resin for VIMP

The chemorheological behaviors of a low viscosity epoxy resin system （Huntsman 1564/3486） for vacuum infusion moulding process （VIMP） were studied with viscosity experiments.The dual-Arrhenius rheological model and the engineering viscosity model were established and compared with the experimental data.The result showed that the viscosity in the earlier stage calculated by dual-Arrhenius model were smaller than the experimental data,while the data calculated by the engineering model were larger.Combining the two models together can predict the rheological behaviors of the resin system in a more credible manner.The processing windows of the resin system for VIMP were determined based on the two models.The optimum processing temperature is 30-45 ℃.

Flexural Properties of Grooved Perforation Sandwich Composites

Selecting H-60 PVC foam, four-axis E-glass non-woven fabric and vinyl resin, a type of innovative reinforced sandwich composite as grooved perforation sandwich （GPS） were fabricated by VIMP. The interfacial structure between the face and core of the sandwich is innovative because of the acuminate grooves in both sides of foam core and the holes perforated along core’s height. The fabrication results show that VIMP is a high-speed and cost-effective manufacturing method. The mechanical properties of the reinforced foam core were tested. The typical flexural failure modes of sandwich specimens were observed. The flexural stiffness and ultimate bearing capacity of sandwich were studied by ordinary sandwich beam theory and finite element method.

Prediction of the Enhanced Out-of-Plane Thermal Conductivity of Carbon Fiber Composites Produced by VARTM

The thermal conductivity of epoxy resin can be increased by a factor of eight to ten by loading with highly conductive particles. However, higher loadings increase the viscosity of the resin and hamper its use for liquid composite molding processes. Thus, the enhancement of the out-of-plane thermal conductivity of carbon composites manufactured by VARTM and accomplished by matrix filling is limited to about 250%. In order to derive higher increases in out-of-plane thermal conductivity, additional measures have to be taken. These consist of introducing thermally conductive fibers in out-of-plane direction of the preform using a 3D-weaving process. Measured out-of-plane thermal conductivities of 3D-woven fabric composites are significantly increased compared to a typical laminated composite. It has been shown that if introducing highly conductive z-fibers, the use of a particle filled resin is not necessary and furthermore should be avoided due to the manufacturing problems mentioned above. An existing analytical model was altered to predict the effective thermal conductivity as a function of the composite material properties such as the thermal conductivities and volume contents of fibers in in-plane and out-of-plane directions, the thermal conductivity of the loaded resin, the grid-density of the out- of-plane fibers, and material properties of the contacting material. The predicted results are compared with measured data of manufactured samples.

Effect of Bio-filler on Hybrid Sisal-Banana-Kenaf-Flax Based Epoxy Composites:A Statistical Correlation on Flexural Strength

This work deals with the investigation of the synergistic effect of bagasse ash with sisal-banana-kenaf-flax fibers reinforced epoxy composite for their flexural behavior.The composites with three combinations of hybrid fibers viz.sisal/kenaf(HSK),banana/kenaf(HBK),and banana/flax(HBF)with bagasse ash(BGA)as filler material are fabricated using vacuum bag assisted resin transfer molding.Experiments were conducted based on L27 orthogonal array to understand the influence of control factor viz.fiber volume,alkali concentration&BGA over output response.A'-ray micro computed tomography analysis was conducted over the developed sample to infer the uniform dispersion of fiber and filler material.The experimental results reveal that the addition of fiber up to 30 vol%depicts better strength and further addition results in a negative impact.Increasing in order of BGA decreases the flexural strength of the developed composites.