الفهرس 
AcknowledgementOnly 14 pages are availabe for public view
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Abstract
Three dimensional (3-D) braiding technology using high performance fiber for advanced composite structures is receiving great attention as a result of the outstanding mechanical and thermoelastic properties of the materials produced. The objective of this research is to study the effect of braid parameters on the mechanical properties of the 3-D braided composite material.
Based on theoretical models for the braided structures and 4-step technique as well as braiding machine, the 3-D braided composite perform are established. The braid parameters of the performs including surface angle, fiber volume fraction and linear density are used to study their effect on the mechanical properties of the 3-D braided composite such as 3-point bending used to calculate the maximum specific strength and the shear test used to calculate the maximum shear strength.
3-D braiding also provides a great ease for forming complex structural shapes which can directly fabricate the performs into the shapes of the final composite operation.
Numerous components, such as engine blocks, helicopter rotor blades, rotor shafts, torque rods, leaf springs, turbine components, brakes piston rings, fly wheels ever since have been made from advanced composites with fiber/textile structure reinforcements.
For determined fiber matrix materials with proper impregnation and curing conditions, the fiber geometry and volume fraction play dominant roles in determining the properties of composite materials and consequently their performances in end uses.
Experimental investigations have been carried out to validate the theoretical model and the results supporting it.
It was clear from these investigations that the increase in the surface angle leads to a significant increase in the fiber volume fraction, as well as an increase in the linear density (gm/mm) and the increase in the maximum specific strength is due to the increase in the fiber volume fraction, the lowest maximum strength is observed for non-braided samples. On the other hand, the highest maximum specific stress is obtained in non-axial samples.
In general, it is noted that the maximum specific strength showed an increase in its value as the percent of axial fiber increases.