A special type of jute fiber woven mat was introduced by a hand loom. Epoxy jute fiber composites were fabricated using the woven fiber mat. A series of jute-hybrid epoxy composites based on the arrangement of the direction of jute fibers, and additional material were introduced to ensure the elevated mechanical properties of the composites. Improved mechanical properties were found in some cases of hybrid epoxy composites. It is discussed that the mechanical behavior is related to the fiber orientation, types of additional materials used in hybrid materials. The purpose of this study is to propose a simple technical method to prepare woven jute fiber mat by hand loom, and to produce epoxy jute fiber, hybrid composite materials to exhibit the elevated mechanical properties.

The main concern of this work is to investigate the influence of number and orientation of ply on tensile properties of hybrid composites. Hybrid composites are those materials which consist of two or more distinct fibers embedded in the same matrix. For this analysis, the elastic behavior of individual fiber-reinforced composite lamina is required. The properties of a single lamina of composites can be determined by the micromechanical homogenization. From this analysis, it is seen that elastic modulus, Poisson's ratio, and shear modulus are the functions of the volume fraction of the fiber and matrix. These properties can be further used for analysis of hybrid composite laminate. In this work different hybrid composites material with a different number of plies and orientations are used to simulate with finite element software. At first, a 3D model of three-ply is used for the simulation. The other model with four, five and six-ply has been used. The influence of number and orientation of ply on tensile properties of hybrid composites is the main goal of the work. The comparison of stiffness between different ply models has established that the number ply influences the strength of hybrid composites. From this work, it is seen that as number ply increases the tensile strength also increases. For the investigation of the influence of the ply orientation, different orientations of ply are used. From different simulation results, it is seen that ply orientation with 0 0 is the best for the tensile strength.

The fatigue strengths in notched specimens of carbon-carbon composites were investigated. Slits of different length were cut on both sides of a test section to investigate the impact of notch sensitivity on fatigue life. Specimens with blunt-notches on the both side of the specimen, and center hole were also used to compare the critical stress, sw. The fatigue limit was measured using S-N curves. From the experimental result, it was found that specimens with blunt-notches have lowest fatigue limit. The relationships between critical stress, sw and specimen geometry were investigated by stress concentration factor, Kt and stress intensity factor, KI which was done two dimensional body forced methods. Consequently, it was discussed that the damage condition in the vicinity of the notch or slit, and the crack initiation behavior affects the fatigue strength. Also, the S-N curve and fatigue limit was related to the crack growth in shear mode.