Dynamic mechanical analysis of banana fiber reinforced polyester composites

Thermosetting (bio)materials derived from renewable resources: A critical review

Damping studies in fiber-reinforced composites : a review

Dynamic mechanical analysis of randomly oriented intimately mixed short banana/sisal hybrid fibre reinforced polyester composites

Thermal and dynamic mechanical analysis of polystyrene composites reinforced with short sisal fibres

This article presents a review of the kinetic studies on the cure reactions of thermosetting resins. The emphasis is placed on those conducted using the thermal analysis by differential scanning calorimetry. Two important categories of kinetic models are discussed and some existing parameter estimation techniques are presented. A variety of factors affecting the cure reactions, including the formulation of cure and process variables, are discussed. At the end, two different approaches in modeling the chemoviscosity of polymeric reactive systems are presented and some existing chemorheological models developed based on these approaches are briefly reviewed.

Kinetic studies of thermoset cure reactions: A review

As new developments are brought to the group of manufacturing processes for composite parts known as liquid composites molding (LCM), the compaction behavior of the textile reinforcements is increasingly seen as an important parameter of the definition of these processes. The evolution of the permeability tensor of the reinforcements with time, the general kinetics of the manufacturing operations, and the modelization of these processes depend on a large extent on the compaction behavior of the reinforcements used, especially in flexible-wall RTM and autoclave molding. Also, more research efforts are devoted toward the development of a complete analytical model of the properties of heterogeneous textile reinforcements. In this paper the published experimental data related to the compaction and relaxation of random mats and woven reinforcements are gathered. Observed parameters are defined, which allow numerical comparisons of the experimental curves to be made, as well as the identification of general trends seen with most tested reinforcements. The effects of various processing parameters are identified, and relations to published analytical models of the mechanical properties of fibrous assemblies are discussed.

Compaction of textile reinforcements for composites manufacturing. I: Review of experimental results

As large components of fiber reinforced composite materials are being more frequently produced by Resin Transfer Molding (RTM), a computer simulation of the injection process can help the mold designer to accomplish three important tasks: (1) to ensure a complete filling of the mold through adequate positioning of the injection ports and of the air vents; (2) to verify the integrity of the mold during the filling process through knowledge of the pressure distribution; and (3) to optimize the production cycle using information about the filling time. The resin impregnation is usually modeled as a flow through a porous medium. It is governed by Darcy's law, which states that the flow rate is proportional to the pressure gradient. In our model, Darcy equation is solved at each time step inside the saturated part of the mold using nonconforming finite elements. This method was chosen because the approximated flow rates, contrary to conforming finite elements, satisfy locally the important physical condition of resin conservation across inter-element boundaries. This permits simplification of the numerical procedure. It is no longer necessary to resort to a control volume approach to move the flow front forward. The resin pressure distribution and the resin front positions are obtained by the computer simulation and calculated results for selected mold geometries are compared with experimental observations. Molds with inserts, multiple injection ports, and the case of anisotropic preforms can be analyzed by the computer program. © 1993 by John Wiley & Sons, Inc.

Numerical analysis of the resin transfer molding process by the finite element method

The application of dynamic mechanical analysis (DMA) for quantifying interfacial interactions in composites is briefly reviewed. Carbon fiber/epoxy composites with fiber volume fractions of 12, 17, 38 and 61 vol% were subjected to flexural deformation on a Dupont DMA 983 instrument. The dependencies of dynamic mechanical properties of the composites on experimental parameters such as oscillation mode, amplitude, frequency, and temperature were investigate. As opposed to the storage modulus, the loss modulus is found to be sensitive to all parameters. In a fixed multiple frequency mode, the loss modulus of the composites increases with oscillation amplitude and decreases with frequency and the number of tests. The information produced in the resonant mode is more reproducible. An additional damping at the interfaces, apart from those of the constituents, suggests a poor interface adhesion in these composites. A linear relationship between the excess damping at the interfaces and the fiber volume fraction shows a similar interface quality for these composites having different fiber volume fractions. The detection of interfacial properities was found to be more sensitive in the flexural deformation mode than in the torsional mode. At temperatures higher than the glass transition temperature of the matrix, the effective volume fraction of the matrix is reduced. Such a reduction can be interpreted from the mismatch of thermal expansion of the matrix and the fibers.

Application of dynamic mechanical analysis for the study of the interfacial region in carbon fiber/epoxy composite materials

Continuous fiber reinforced polymer composites can be produced by the injection of a reactive fluid into a mold with preplaced reinforcement. Mold filling modeling softwares such as our RTMFLOT software are being developed to help design and production engineers meet their requirements for part production. The utilization of accurate permeability values is an absolute necessity for relevant mold filling simulation. This paper presents permeability results for several reinforcements. Experimental techniques being used to measure the permeability are also discussed. Several points are highlighted and suggestions are made to help the investigator in the search for reliable permeability data.

R. Gauvin

Papers

Kinetic studies of thermoset cure reactions: A review

Compaction of textile reinforcements for composites manufacturing. I: Review of experimental results

Numerical analysis of the resin transfer molding process by the finite element method

Application of dynamic mechanical analysis for the study of the interfacial region in carbon fiber/epoxy composite materials

Permeability measurement and flow simulation through fiber reinforcement