الفهرس 
CHAPTER 1: INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
Fiber reinforced polymer composites have many applications as a class of structural materials because of their ease of fabrication, relatively low cost and superior mechanical and dynamic properties.
A hybrid composite is a material which consists of two or more types of reinforcing fibers in one or more types of matrices. By hybridizing two or more types of fiber in a matrix allows a closer tailoring of composite properties to satisfy specific requirements. The two or more fiber materials used in hybrid systems combine the benefits of each fiber into a single composite product. Hybrid composites have long taken the attention of many researchers as a way to enhance composites properties.
The present work includes the fabrication of three non-hybrid composite laminates in the form of [C/C/C/C/C], [G/G/G/G/G] and [B/B/B/B/B] and six hybrid composite laminates in the form of [C/C/G/C/C], [C/C/B/C/C], [G/G/C/G/G], [G/G/B/G/G], [B/B/C/B/B] and [B/B/G/B/B] using hand lay-up technique at room temperature, with various fiber configurations. where C, G and B are refers to carbon, glass and basalt fibers, respectively.
Monotonic mechanical properties of non-hybrid and hybrid composites laminate such as tensile, flexural, inter-laminar shear strength and impact strength were investigated. Monotonic dynamic response of non-hybrid and hybrid composite laminates under pulse load was studied theoretically and experimentally by evaluating natural frequencies, damping factor and mode shape of non-hybrid and hybrid composite laminates at various staking sequence with four types of boundary fixations. The theoretical part was performed with the help of the finite element analysis software. In the iii
experimental part, modal analysis technique ”frequency response functions” (FRF) was applied.
The mechanical test results show that the reinforcement with adding the basalt fabric and carbon fabric based unsaturated polyester composites as a fiber configuration [C/C/B/C/C] enhanced the mechanical properties of the hybrid composite laminates among other various stacking sequences. It was found that the largest values of tensile, flexural strength and inter-laminar shear strength (ILSS) were 109.76, 608.4, 25.35 MPa, respectively. The results show the good bonding adhesion at the interface between the fibers and matrix of the non-hybrid and hybrid composite laminates. The impact energy and impact strength with stacking sequences [C/C/G/C/C] have the largest value at 3.73 Joule and 37.2 KJ/mm2, respectively as compared with the other composite and different stacking sequences.
The dynamic test illustrated that the damping factor at different boundary conditions enhanced when number of basalt fiber layers is increased. So the specimen with code B [B/B/B/B/B] has the highest damping factor compared to the other stacking sequences where a value of (0.324%) was given for clamped-free damping factor sample. While the specimen with code C [C/C/C/C/C] has the lowest values compared to the other stacking sequences (0.091%) for clamped-free damping factor. Regarding boundary conditions, it was found that damped-free fixation gave the highest damping values.
Natural frequency at different boundary fixations was enhanced when number of carbon fiber layers is increased simply due to the high stiffness of carbon fibers. Illustrated also natural frequency has the best values at boundary fixation clamped-clamped. The comparison between experimental and numerical model shows the efficiency of the proposed mathematical model of the composite structural specimen with bonded points.
The developed hybrid composites with enhanced performance over a wide range of properties will lead to new applications in various sectors of construction and automotive industries.