The mechanical properties of the glass fiber reinforced Polyamide (PA6) composites made by prepreg tapes and commingled yarns were studied by in-plane compression, short-beam shear, and flexural tests. The composites were fabricated with different fiber volume contents (prepregs-47%, 55%, 60%, and commingled-48%, 48%, 49%, respectively) by using vacuum consolidation technique. To evaluate laminate quality in terms of fiber wet-out at filament level, homogeneity of fiber/matrix distribution, and matrix/ fiber bonding standard microscopic methods like optical microscopy and scanning electron microscopy (SEM) were used. Both commingled and prepreg glass fiber/PA6 composites (with V f 48%) give mechanical properties such as compression strength (530-570 MPa), inter-laminar shear strength (70-80 MPa), and transverse strength (80-90 MPa). By increasing small percentage in the fiber content show significant rise in compression strength, slight decrease in the ILSS and transverse strengths, whereas semipreg give very poor properties with the slight increase in fiber content. Overall comparison of mechanical properties indicates commingled glass fiber/PA6 composite shows much better performance compared with prepregs due to uniform distribution of fiber and matrix, better meltimpregnation while processing, perfect alignment of glass fibers in the composite. This study proves again that the presence of voids and poor interface bonding between matrix/fiber leads to decrease in the mechanical properties. Fractographic characterization of postfailure surfaces reveals information about the cause and sequence of failure. POLYM. COMPOS., 00:000-000,

The aim of this study was to understand the role of the processing in determining the mechanical properties of glass fibre reinforced polybutylene terephthalate composites (Glass/PBT). Unidirectional (UD) composite laminates were manufactured by the vacuum consolidation technique using three different material systems included in this study; Glass/CBT (CBT160 powder based resin), Glass/PBT (prepreg tapes), and Glass/PBT (commingled yarns). The different types of thermoplastic polymer resin systems used for the manufacturing of the composite UD laminate dictate the differences in final mechanical properties which were evaluated by through compression, flexural and short beam transverse bending tests. Microscopy was used to evaluate the quality of the processed laminates, and fractography was used to characterize the observed failure modes. The study provides an improved understanding of the relationships between processing methods, resin characteristics, and mechanical performance of thermoplastic resin composite materials.

This paper describes the development of a thermoplastic composite system for structural application in the chassis of an electrically propelled bus. The work involved the characterisation and modelling of a vacuum bag moulding process using a woven commingled thermoplastic composite precursor. The matrix materials were PET and a PET copolymer. The process employs an ambient pressure oven, with tooling that can be made from composite, metal or ceramic. The process results in good quality laminates, with a void content generally lower than 1%. The temperature pro le through the part and the consolidation behaviour were characterised and modelled. It was found that the thermal pro le could be modelled with adequate accuracy using 'single point' values of thermal properties. Experimental measurements showed, for the rst time, that consolidation occurs in two stages: a low temperature solid state debulking near to T g , followed by full melt impregnation at a higher temperature (above T m in the case of the homopolymer). Both stages in the consolidation process were modelled separately using a simpli ed version of the Kamal equation.PRC/1818 INTRODUCTIONHowever, for medium volume production runs of This project involved the development and characterlarger parts, polymer composite tooling oVers many isation of a vacuum bag process for the manufacture attractions, including the ease with which doubly of thermoplastic composite parts on a size and scale curved shapes can be produced. Moreover, improved suitable for lightweight public transport vehicles. The resin chemistry has resulted in composite tooling with study centred on the replacement of load bearing signi cantly improved high temperature capability. chassis components of the electric bus shown in Fig. 1.In the present project, glass-cyanate ester tools were One of the challenges of the project was the use of supplied by ACG of Heanor, UK. These were found tooling made from a composite with a polymeric to work well with the PET copolymer for repeated matrix. This posed some problems due to the high mouldings. processing temperatures (in the range 200-300°C),The bene ts of using thermoplastic composite which limited the range of tooling materials that technology1-5 include emission free processing and could be used. Of course metal tooling may be recyclability of both intermediate factory scrap and nal employed for this application, and certain ceramic product. Since both the homopolymer and the based materials1 have also been found to be viable. copolymer used in the present study are derivatives of PET, the starting material can, in principle, be derived from the established PET recyclate stream. The availability of a lightweight thermoplastic composite will also promote the use of energy eYcient transport. Thermoplastic composites have been investigated for several transport applications, but attention to date has focused mainly on polypropylene (PP) matrixes.2 This has occurred mainly because PP composites are the most generally available thermoplastic compos...

This paper presents a method for calculating pressure and oil flow in a section of an oil-filled cable at load variations with due regard to both the hydraulic resistance of the oil canals and the elasticity of the sheath and the pressure armor, if any, and the compressibility of the oil. The present article restricts itself to cable sections terminated with oil reservoirs in which the pressure is constant; in a forthcoming paper this restriction will be dropped. Formulas are given for pressure, oil current, and amount of oil which flows through a cross section of the cable for an arbitrarily prescribed oil expansion per unit length. These formulas are applied to the following oil expansion functions: S0·1, d/dt(N0·1), e−t/T·1, and 1/√t·1, which represent the oil expansion or terms occurring in the series giving the oil expansion in some important cases. Generalized functions are plotted for the pressure at the midpoint, the oil current at the endpoints, and the amount of oil which passes the endpoints for the above mentioned oil expansion functions. Using these generalized functions, the calculation of pressure and oil flow, with the simplifying assumptions made here, is reduced to elementary operations. Numerical examples illustrate the use of the given formulas and curves.