A. Tuğrul Seyhan

Investigating the effects of a polyester preforming binder on the mechanical and ballistic performance of E-glass fiber reinforced polyester composites

Abstract An experimental investigation was carried out to determine the effects of a preforming binder on the mechanical properties and ballistic performance of E-glass-fiber/polyester composite systems. The glass preforms were consolidated by application of heat and pressure over plies of the glass fabrics coated with various concentrations of a thermoplastic polyester binder. The peel strength of the preforms with various binder content was measured and the highest peel strength was obtained from preforms prepared with about 9 wt % of the binder. Composite laminates with and without binder were fabricated using VARTM technique and the effects of the binder on the composite mechanical properties were evaluated. It was found that the flexural strength and mode I interlaminar fracture toughness decreases by 15% and 40%, respectively, due to the presence of 3 wt % of the binder. Ballistic test was performed on E-glass/polyester composite panels using 1.1-g fragment-simulating projectiles and it was found that the binder amount has some considerable effect on the damage extension of the impacted composites. The results showed that the preforming binder has significant potential to tailor composite properties.

A Statistical Study of Fatigue Life Prediction of Fibre Reinforced Polymer Composites

In this study, the tension-tension fatigue response of bidirectional woven E-glass fibre reinforced unsaturated polyester composites was experimentally determined. The composite parts were produced via continuous laminating process. The probabilistic fatigue life distribution of the produced composites at various constant stress levels was then modelled, based on the two-parameter Weibull approach. A variety of different methods including graphical, method of moments and the maximum likelihood were conducted to predict the Weibull parameters. For the sake of reliability, the composite fatigue life data gathered at each constant stress level were correlated with the approvals of Kolmogorov-Smirnow goodness-of-fit test. Furthermore, the two parameter Weibull approach was utilized to relate the composite failure probability to the number of fatigue cycles that the composite withstands under a given load. As a result, the two-parameter Weibull approach has proved to be an efficient statistical tool to assess the reliability of polymer composite structures.

Scanning Transmission Electron Microscopy of SiAlON/Graphene Nano Platelets Composites Obtained with a Novel Homogenization Approach

SiAlON ceramics have gained attraction as an engineering material due to their superior mechanical properties, thermal stability, creep resistance and corrosion resistance [1]. Thanks to its properties these ceramics are used for engineering applications like cutting tools, ball bearings and etc, where not only the mechanical properties but also thermal conductivity has significant importance in order to remove produced heat from work zone [2]. Graphene is the most promising candidate to improve thermal conductivity due to its extraordinary thermal properties to overcome heat transfer problem from work zone [3]. Graphene addition can also improve the electrical conductivity of naturally electrical insulator SiAlON ceramics and this can allow electro-discharge machining for shaping and manufacturing.