الفهرس 
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Abstract
1.3. Thesis objectives
The objective of this thesis is to optimize the NPT performance on unpaved terrain. To achieve that, NPT of preferable types of spokes shapes have been established in previous research, then select the suitable one with the soil conditions to optimize it. To accomplish this work, three different configurations of NPTs considered named Lattice, Spoke-Pairs and Honeycomb have been developed and analyzed by using ABAQUS, commercial finite element analysis software, then selected the best shape to optimize it. Tyre structural optimization performed on three design variables, (i) spoke thickness, (ii) thickness of the shear band, and (iii) tread thickness, while maximum contact pressure and vertical stiffness were subjected to constraints to minimize the rolling resistance. Design of experiments (DOE) accomplished to measure the three design variables affection on a response of rolling resistance to meet the requirements of the constraints then a response surface method (RSM) was used for the approximation between the three variables and the response of the objective function by using an optimization algorithm.
Besides, investigated the tyre performance by adding carbon nanotubes (CNTs) on polyurethane (PU), which is the primary material using in NPT to improve the mechanical strength and thermal stability by adding 2% by weight of CNTs. Finally, replacement continuous shear band with another have porous volume was studied because the shear band is the second most important component in the NPT. The pores are made of hexagonal shape to have high lateral stiffness and shear strain. The optimized, PU/CNT, and porous models validated compared with the initial model.
1. ABSTRACT
Extensive studies have been proposed for Non-Pneumatic Tyres (NPTs) in both light and heavy equipment as these tyres have low energy loss, puncture-proof, long live without maintenance rather than the traditional pneumatic tyre. Many studies were focused on the geometry and structure of elastomer material adaptation, as this is the primary material used in the NPTs.
The objective of this thesis is to optimize the NPT performance on unpaved terrain. To achieve this, three NPT models were designed inspired by the preferable types of spokes shapes in the previous research, then the suitable one was selected according to the soil conditions to optimize it. Tyre structural optimization performed on three design variables. (i) spoke thickness, (ii) thickness of the shear band, and (iii) tread thickness, while maximum contact pressure and vertical stiffness were subjected to constraints to minimize the rolling resistance. Design of experiments (DOE) accomplished to measure the three design variables effect on a response of rolling resistance to meet the requirements of the constraints then a response surface method (RSM) was used for the approximation between the three variables and the response of the objective function by using an optimization algorithm. Besides, investigated the tyre performance by adding carbon nanotubes (CNTs) on polyurethane (PU), which is the primary material used in NPT to improve the mechanical strength and thermal stability by adding 2% by weight of CNTs. Moreover, the replacement of a continuous shear band with another which has porous volume was studied. The optimized, PU/CNT, and porous models validated compared with the initial model