Mehmet Emin Deniz

Residual failure pressures and fatigue life of filament-wound composite pipes subjected to lateral impact

This study presents the effect of impact energy on the static failure pressures, and fatigue life of composite pipes. The specimens manufactured have inner diameter 100 mm and length 400 mm. Impact tests were realized at three different energy levels 5.0, 7.5, and 10.0 J. Force–deflection curves were plotted. Impacted and non-impacted specimens were subjected to internal pressure statically and dynamically to obtain failure pressure and fatigue life of the composite pipe, respectively. Results indicate that leakage and eruption pressures for static test decrease and perspiration, leakage, and eruption cycles decrease by lateral impact.

On the residual compressive strength of the glass-epoxy tubes subjected to transverse impact loading

This experimental study discusses the effects of the tube diameter and the impact energy level on the impact and compression after impact behaviors of [±55]3 filament-wound glass/epoxy composite tubes. Four different tube diameters were selected as 50, 75, 100, and 150 mm. The composite tubes were subjected to various impact energy levels, 15, 20, and 25 J, using an instrumented impact testing machine at room temperature. Impacted and nonimpacted samples were subjected to axial compression tests. Results indicated that both specimen diameter and impact energy highly affect the impact response and compression-after impact strength of composite tubes.

Failure Pressures of Composite Cylinders With a Plastic Liner

The present experimental study deals with the temperature and the stacking sequence effects on the response of the composite cylinders under the internal pressure. GRP composite cylinders were manufactured by using E-glass fibers and epoxy resin and tested for the close-ended condition. Test specimens were manufactured of four antisymmetric layers with [θ°/-θ°/θ° /-θ°]2 orientations with five different winding angles over a plastic liner. Filament wound cylinders were subjected to internal pressure at four different temperatures such as 2°C, 25°C, 60°C, and 80°C. The aim of this study was to investigate the thermal effect on the failure pressures of filament wound cylindrical composites according to different fiber orientation angles subjected to internal pressure loading at various temperatures. The results show that the orientation angle and the temperature have significant effects on the failure pressures of the composite cylinders.

Transverse impact and axial compression behaviors of glass/epoxy pipes subjected to seawater and impact loading

This article investigates the effects of seawater and impact loading on the impact behavior and compressive strength of impacted glass/epoxy composite pipes. The specimens were immersed into artificial seawater at laboratory conditions for 3, 6, 9, and 12 months. First, the impact tests were carried out on composite pipes at room temperature, and then, the axial compression tests were performed. The results of immersed samples were compared with that of reference specimens (dry). Seawater effect on the force–deflection behavior and failure mechanism is more than impact energy with increase in pipe diameter, while impact energy effect is more dominant than seawater effect for small diameters of the pipe. Compressive strength generally reduces with increase in seawater immersion time and specimen diameter except for the highest diameter.

Effect of seawater on pin-loaded laminated composites

Abstract The aim of this study was to investigate the effect of seawater on bearing strength of glass-epoxy laminated composites. The ratio of the edge distance to pin diameter (E/D) was changed from 1 to 5 and that of the specimen width to pin diameter (W/D) was selected as 3 and 4 for this study. The hole of the specimen was subjected to a traction force induced by a pin. Laminated composite plates were manufactured at the Company Izoreel Composites. Tension tests were performed on pinned joint specimens with a stacking sequence of [0/90]3S. The specimens were immersed in seawater of the Aegean Sea having a salinity of about 3.5 wt.-% in a glass aquarium at laboratory for 1, 3, 6, 9 and 12 months. For each period of immersion time, failure modes and maximum failure loads of the specimens were found experimentally. The maximum reduction of the bearing strength was obtained as 38% for E/D = 3 and W/D = 3 due to the seawater effect.

Environmental Effects on Mechanical Properties of Glass-Epoxy Composites

Abstract This study presents the effects of seawater and distilled water immersion time periods on mechanical properties of unidirectional glass reinforced epoxy composites. Tension, compression, and shear test specimens exposed to seawater and distilled water were prepared according to ASTM standards. After tests, SEM imaging of fracture surface of specimens was made. Results showed that seawater and distilled water immersion time affects significantly mechanical properties and strength values of glass-epoxy composites.

Determination of Mechanical Properties and Failure Pressure in Composite Cylinders

Abstract In this study, mechanical properties of cylindrical composite specimens were measured experimentally. Composite cylinders oriented at 0° C and 90° were manufactured by using the hand lay -up technique. The cylinders were loaded axially for measuring the axial tensile strength and compressive strengths. Some specimens were attached to a torsion machine for measuring shear strength and shear modulus. Thus, a close and true measuring was performed in the cylindrical specimens. A finite element solution was performed in closed ended composite cylinders under internal pressure and thermal loading. Thermal stresses occur at low and high temperatures with respect to the room temperature. For a true or close solution in composite cylinders, mechanical properties should be determined in cylindrical composite specimens.