Juan Pablo Torres

Manufacture of Green-Composite Sandwich Structures with Basalt Fiber and Bioepoxy Resin

Nowadays, there is a growing interest for the use and development of materials synthesized from renewable sources in the polymer composites manufacturing industry; this applies for both matrix and reinforcement components. In the present research, a novel basalt fibre reinforced (BFR) bioepoxy green composite is proposed as an environmentally friendly alternative to traditional petroleum-derived composites. In addition, this material system was combined with cork as core material for the fabrication of fibre composite sandwich structures. Mechanical properties of both skin and core materials were assessed through flexural and tensile tests. Finite element (FEM) simulations for the mechanical stress analysis of the sandwich material were carried out, and a maximum allowable shear stress for material failure under bending loads was established. Permeability measurements of the basalt fabrics were carried out in order to perform numerical simulations of liquid composite moulding (LCM) processes on the PAM-RTM software. The proposed green-composite sandwich material was used for the fabrication of a longboard as a case study for a sports equipment application. Numerical simulations of the mould filling stage allowed the determination of an optimal mould filling strategy. Finally, the load-bearing capacity of the board was studied by means of FEM simulations, and the presented design proved to be acceptable for service.

Experimental and numerical analysis of drop-weight low-velocity impact tests on hybrid titanium composite laminates:

An experimental and numerical study on low-velocity impact responses on [Ti/0/90] s hybrid titanium composite laminates (HTCLs) is presented. Different energy levels from 10 to 40 J are investigated using a drop-weight instrument and post-impact inspection. An explicit finite element implementation provides a detailed analysis of impact response in composite and titanium layers, respectively. It accounts for interfacial debonding, progressive failure in composite plies and elastic–plastic deformation in titanium. The main failure modes are experimentally and numerically found to be debonding between titanium and composite, matrix cracking and interlaminar delamination. The principal energy-absorbing mechanism is plastic dissipation of the two titanium sheets. The low cost numerical model is able to effectively predict the overall impact response and major failure modes with good accuracy.

Statistical data for the tensile properties of natural fibre composites

This article features a large statistical database on the tensile properties of natural fibre reinforced composite laminates. The data presented here corresponds to a comprehensive experimental testing program of several composite systems including: different material constituents (epoxy and vinyl ester resins; flax, jute and carbon fibres), different fibre configurations (short-fibre mats, unidirectional, and plain, twill and satin woven fabrics) and different fibre orientations (0°, 90°, and [0,90] angle plies). For each material, ~50 specimens were tested under uniaxial tensile loading. Here, we provide the complete set of stress–strain curves together with the statistical distributions of their calculated elastic modulus, strength and failure strain. The data is also provided as support material for the research article: “The mechanical properties of natural fibre composite laminates: A statistical study” [1].