Evaluation of the quality of surface finish of messassa wood for three types of varnishes.

The aim of this study was to evaluate the performance of the messassa wood Brachystegia spiciformis and Julbernardia globiflora for three types of finishing products for use in the furniture and frames industries. Coating performance was assessed by adhesion strength, impact deformation resistance, abrasiveness, gloss and overall color variation tests based on technical standards. Copal painting application was higher for gloss, adhesion and lower abrasiveness compared to water based and polyurethane. The impact deformation was higher for polyurethane than water-based and copal for both species. The darkening of wood for Brachystegia spiciformis and a slight lightening of wood by Julbernardia globiflora characterize the overall color variation after application of the coating products. According to these results, the varnishes can be used to add value to the messassa wood as a finish in solid wood furniture and frames.

DYNAMIC IMPACT WEAR AND IMPACT RESISTANCE OF W-B-C COATINGS

Coated components used in industry are often exposed to repetitive dynamic impact load. The dynamic impact test is a suitable method for the study of thin protective coatings under such conditions. Aim of this paper is to describe the method of dynamic impact testing and the novel concepts of evaluation of the impact test results, such as the impact resistance and the impact deformation rate. All of the presented results were obtained by testing two W-B-C coatings with different C/W ratio. Different impact test results are discussed with respect to the coatings microstructure, the chemical and phase composition, and the mechanical properties. It is shown that coating adhesion to the HSS substrate played a crucial role in the coatings’ impact lifetime.

A Numerical Assessment on the Influences of Material Toughness on the Crashworthiness of a Composite Fuselage Barrel

In the present work, a numerical study on the dynamic response of a composite fuselage barrel, in relation to crashworthiness, has been investigated. The aim of this work is to investigate the influence of the material fracture toughness on the capability of a composite fuselage barrel to tolerate an impact on a rigid surface. Three different material configurations with different intra-laminar fracture energy values were considered to take into account variations in material toughness. Indeed, the dynamic behaviour of the analysed fuselage barrel has been numerically simulated by means of the FE (Finite Element) code Abaqus/Explicit. The effects of intralaminar fracture energy variations on the impact deformation of the barrel has been evaluated comparing the numerical results in terms of displacements and damage evolution for the three analysed material configurations.