Development of High Strength Bio-Composite Material for Light Weight Serial Robot Mechanisms

This work focuses on the development and characterization of natural fiber composites material suitable for light weight serial robot mechanisms. The high strength and toughness of Signature spider silk and Bombyx Mori silkworm silk and their multifunctional nature motivated to do this research work. Uniaxial tension test and hardness test were performed for composition of spider silk, silkworm silk and matrix taken in four samples with proportions 20/50/30, 25/45/30, 30/40/30, and 35/35/30 respectively with spider silk, silkworm silk and matrix by weight. Experimentally, the elastic properties were evaluated by tension test and hardness test as per ASTM standards. While the rule of mixtures was used in the evaluation of properties of composites in the fiber direction, the evaluation of properties perpendicular or transverse to the fiber direction was done based on the Brintrup equation and Halpin–Tai equations. The results indicated that the Young's modulus in both the linear directions improved by the inclusion of vinyl ester, whereas Poisson's ratio is decreased. The Tensile strength of its composite materials was tested and its distribution was analyzed based on the normal distribution model. The maximum normed residual (MNR) test was applied to eliminate abnormal data. It suggests that the normal distribution can be used to express the tensile strength. The probability distribution of composite material based on tensile strength was also calculated. The material developed can be used for the fabrication of serial robot mechanisms with reduced self weight and vibration issues.