J. C. Velosa

Mechanical behavior of novel sandwich composite panels based on 3D-knitted spacer fabrics

In the present work, the mechanical performance of novel sandwich composite panels based on 3D-knitted spacer fabrics has been investigated. Composite panels were produced using three different types of spacer fabrics having different structural parameters. The sandwich panels were fabricated based on an unsaturated polyester resin using a modified vacuum-assisted resin transfer molding process which allowed the formation of low-density core structures. The produced sandwich composite panels were characterized for flexural, compressive, and impact properties. The effect of different fabric structural parameters (such as cross-thread density, linear density of yarn used in face and core, and structure of face) on the processability and mechanical behavior of composite panels has been thoroughly investigated. The results showed that the composite panels based on spacer fabrics having lesser cross-thread density and made of coarser yarns performed better with respect to compressive and impact properties, whereas the best flexural properties were obtained in case of spacer fabrics with high cross-thread density and made of finer yarns.

Application of Taguchi method in optimizing fabrication of composite panels for interior dividing walls

In order to save material and energy, an increased growth can be noticed in recent times in the use of low-cost and light-weight solutions for the interior dividing walls of buildings. In this context, the main aim of the present research work was to develop light-weight composite panels based on non-woven fabrics for this application as an alternative to more commonly used materials and to optimize the manufacturing process parameters in order to maximize their mechanical performance. Thermo-bonded nonwoven geo-textiles made from polyester (70%) and polypropylene (30%) fibres were consolidated using compression moulding technique, varying the various structural and process parameters, such as number of layers, compression time, temperature and pressure. Taguchi method was used to design the experiments, as well as to understand the influence of various parameters on tensile and flexural strengths of developed composite panels and to optimize them in order to maximize these properties. According to the analysis, a consolidation temperature of 210°C, pressure of 30 bars, compression time of 35 minutes and 30 layers are required to achieve the maximum values of tensile and flexural strength with minimum variability.

Production, characterization and prediction of mechanical properties of waste fibre reinforced composite panels for application in adjustable partition walls of buildings

In the present paper, waste fibre reinforced composite panels have been developed for application in interior partition walls of buildings. These panels were produced using waste fibres collected from the textile industries and using aminoplastic phenol-formaldehyde resin. Mechanical properties such as tensile, compression and flexural properties of these composite panels were characterized and the influence of a few parameters such as fibre or matrix weight % and composite density on the mechanical properties has been analyzed. Impact properties (soft body and hard body impact), which is very important for the materials used in the partition walls, of the developed composite panels was simulated using finite element method and the influence of composite parameters (fibre or resin content, composite density) on the impact resistance and strain energy was analyzed. Thermal degradation behaviour of the developed composite panels was also investigated. Although the waste fibre reinforced composites show low mechanical properties, the simulation results showed that the composite panels showed required impact properties (no collapse, no penetration or projection under both soft and hard body impact) for their successful application in the interior partition walls. Thermal stability of the composite panels was also sufficient for this application. It was also observed that the composite panels exhibited better impact resistance and lower deformation when produced with higher fibre % as well as higher density.