PhD.Dissertation Defense:Fetiye Esin Yakın
THE COMPARATIVE STUDY ON THE EFFECT OF PROCESS PARAMETERS, THERMAL ENVIRONMENTS, AND THICKNESS VARIATIONS IN THE MANUFACTURING OF THERMOSET COMPOSITES BY VARIOUS FIBER ORIENTATIONS UTILIZATION OF AFP PROCESS
Fetiye Esin YAKIN
Manufacturing Engineering, PhD Dissertation, 2024
Thesis Jury
Assoc. Prof. Hatice Sinem ŞAŞ ÇAYCI (Thesis Advisor), Prof.Mehmet YILDIZ, Prof. Murat SÖZER, Assoc. Prof. Volkan ESKİZEYBEK, Assoc. Prof. Bekir DIZMAN
Date & Time: 20th December, 2024 – 16.00 PM
Place: FENSL058
Zoom link: https://sabanciuniv.zoom.us/j/6938110217?omn=92895581011
Keywords : Automated Fiber Placement Method, Thermoset Based Composite Laminations, Thermal Fluctuation Environment, Ply-Drop Lay-ups, Mechanical Performance
Abstract
Carbon fiber-reinforced polymer composites (CFRPCs) exhibit exceptional stiffness-to-weight ratios and outstanding load-carrying capacities under diverse operational conditions, making them indispensable in aerospace applications for decades. Automated Fiber Placement (AFP) is a cutting-edge manufacturing technique employed to fabricate high-quality composite components with precise fiber orientations and minimal material waste. One of the primary advantages of AFP is its capability to tailor the mechanical behavior of composite materials through strategic adjustments in fiber orientation and laminate thickness. This thesis focuses on the effect of consolidation force, a critical process parameter, on the mechanical and fracture performance of composite laminations produced using AFP. The thesis first investigates the influence of consolidation force variations on the mechanical properties, fracture performance, and damage mechanisms of various stacking sequence laminations under room temperature (RT) conditions. Subsequently, the thesis examines the static, dynamic, and fracture behavior of AFP-produced laminations with different consolidation forces under thermal cycling (TC) environments, simulating fluctuating operational conditions. By comparing RT and TC environments, the findings reveal that thermal cycling enhances the mechanical and fracture behaviors of specific stacking sequences, attributed to the tailored effects of consolidation force. Furthermore, the thesis evaluates the impact of thickness variations on the mechanical performance and damage mechanisms of stacking sequences fabricated via AFP. In conclusion, this research demonstrates that consolidation force is a pivotal process parameter in optimizing the mechanical and fracture properties of composite laminations with varied stacking sequences. The insights provided by the thesis contribute to the advancement of AFP technology for producing reliable, high-performance composite materials under diverse environmental and thickness variation conditions.