Flexural properties of porcupine quill-inspired sandwich panels.

This paper presents the bending behaviour of the porcupine quill and bioinspired Voronoi sandwich panels, aiming to explore the effect of geometrical design on the bending performance of the inspired structures. Through the x-ray micro-computed tomography, the internal morphology of the quill is explored. The longitudinal cross-section of the porcupine quill revealed a functionally graded design in the foam structure. Based on this observation, Voronoi sandwich panels are designed by incorporating the Voronoi seed distribution strategy and gradient transition design configurations. Porcupine-inspired sandwich panels with various core designs are fabricated via material jetting technique and tested under three-point bending condition. Results show that the sample failed at the bottom face panels for uniform sandwich panels, whereas graded samples failed in the core panel. The bending behaviour developed via simulation software shows a good agreement with the experimental results. The parametric study provides insights into structural designs for engineering applications, particularly in the aerospace and automobile industries.

Effects of Carbon Black and the Presence of Static Mechanical Strain on the Swelling of Elastomers in Solvent.

The effect of carbon black on the mechanical properties of elastomers is of great interest, because the filler is one of principal ingredients for the manufacturing of rubber products. While fillers can be used to enhance the properties of elastomers, including stress-free swelling resistance in solvent, it is widely known that the introduction of fillers yields significant inelastic responses of elastomers under cyclic mechanical loading, such as stress-softening, hysteresis and permanent set. When a filled elastomer is under mechanical deformation, the filler acts as a strain amplifier in the rubber matrix. Since the matrix local strain has a profound effect on the material's ability to absorb solvent, the study of the effect of carbon black content on the swelling characteristics of elastomeric components exposed to solvent in the presence of mechanical deformation is a prerequisite for durability analysis. The aim of this study is to investigate the effect of carbon black content on the swelling of elastomers in solvent in the presence of static mechanical strains: simple extension and simple torsion. Three different types of elastomers are considered: unfilled, filled with 33 phr (parts per hundred) and 66 phr of carbon black. The peculiar role of carbon black on the swelling characteristics of elastomers in solvent in the presence of mechanical strain is explored.