Bulent Murat Icten

Progressive failure analysis of pin-loaded carbon–epoxy woven composite plates

Abstract The present investigation deals with the failure strength and failure mode of a pinned-joint carbon–epoxy composite plate of arbitrary orientations. The main objective is to investigate the possibility of predicting the properties of the joint from the properties of the material measured with standard tests. The failure load and the failure mode are analysed numerically and experimentally. A computer program developed for such an analysis is used to calculate the failure load, the failure mode, and the propagation of failure of plate with different fiber orientation, different material properties and different geometries. Hoffman and Hashin failure criteria are used in failure analysis. Experimental results concerning damage progression and ultimate strength of the joint are obtained and compared with predictions. A good agreement between experimental results and numerical predictions is obtained.

Failure analysis of pin-loaded aluminum-glass-epoxy sandwich composite plates

Abstract The aim of this study is to investigate failure load and failure mode in an aluminum–glass–epoxy sandwich composite plate, with a circular hole, which is subjected to a traction force by a pin. To evaluate the effects of joint geometry and fiber orientation on the failure strength and failure mode, parametric studies were performed experimentally. The end distance to diameter (E/D), and width to diameter (W/D) ratios in the plate were changed from 1 to 5 and 2 to 5, respectively. Experimental results show that the first failure load and ultimate failure load increase by increasing E/D and W/D ratios, and when these ratios are equal or greater than 4, full bearing strength occurs.

Failure Strength of Woven Glass Fiber-Epoxy Composites Pinned Joints

In this paper, mechanical behavior and damage development of pin-loaded woven glass fiber-epoxy composites have been observed numerically and experimentally. Parametric studies have been performed to evaluate the effects of joint geometry and ply orientation on the failure strength and failure mode of composite laminates with a pin-loaded hole. For this purpose, a finite element program has been developed. The failure analysis was based on Hashin and Hoffman criteria that were applied at the ply level. The results (with Hashin and Hoffman criteria) were compared to each other. To verify to the numerical predictions of mechanical behavior, a series of experiments was performed with two different material configurations ([(0/90)3]S [(45)3]S) and twenty different geometries. The numerical and experimental results were compared and discussed. A good agreement between experimental results and numerical predictions was obtained.

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.

Impact Behavior of Glass/Epoxy Laminated Composite Plates at High Temperatures

The objective of this study is to investigate the impact behavior of laminated glass/epoxy composite plates with [0/90/0/90]S and [0/90/45/- 45] S stacking sequences at room (~20°C) and high temperatures (60°C and 100°C). The maximum contact force between the impactor and the composite plate, the maximum deflection at the maximum contact force at the center of the composite, and the contact time history were plotted as a function of impact energy. In order to determine the energy absorbing capability of the plates, energy profiling method was used. The results show that the perforation threshold increases with increasing temperature.

Low temperature effect on single and repeated impact behavior of woven glass-epoxy composite plates:

This study deals with the determination of the response of woven glass-epoxy composites to the single and repeated impact loading at room temperature and at −50℃. Single impacts were performed at various energies up to perforation took place and the characteristics such as contact force, contact duration, deflection, and absorbed energy were obtained. In addition, some low energy values were selected for the repeated impact tests. The maximum contact force and absorbed energy versus repeat numbers were given. It was found that temperature is extremely important for determining the response of the composite subjected to single and repeated impact loadings.

Failure Behavior of Composite Laminates with Multi-Pin Loaded Holes

The aim of this study is to determine the failure behavior of laminated glass—epoxy composite plate which is subjected to a traction force by four pins. The failure load and failure mode of composite plates which have the stacking sequence of [0/90/±45]S has been observed experimentally. The ratio of edge distance from the hole center to pin diameter (E/D), the ratio of longitudinal holes distance to pin diameter (F/D) and the ratio of transverse holes distance to pin diameter (G/D) were selected as parameters. The results showed that the specimens except for E/D = 2 have similar behavior in terms of failure loads and failure modes.

Thermal Impact Behavior of Glass-Epoxy-Laminated Composite Plates:

The aim of this study is to investigate the experimental and numerical characterizations of the glass/epoxy composite plates at room temperature (approximately 20°C) and high temperatures (40°C, 60°C, 80°C, and 100°C). Two stacking sequences were selected as [0/90/0/90] S and [0/90/45/—45]S. Numerical analysis was carried out using 3DIMPACT finite element code. The maximum contact force between the impactor and the composite plate, the maximum deflection at the center of the composite, and the percentage of damage area versus impact energy were drawn. Overall damage patterns were found using a light table and obtained by 3DIMPACT code. The numerical predictions showed good agreement with the experimental results.

Effects of Weaving Density and Curing Pressure on Impact Behavior of Woven Composite Plates

In this study, the behavior of woven E-glass epoxy laminated composite plates under transverse central point impact by hemispherical impact nose with 12.7mm diameter was investigated. Loose and tight plain weave layers were manufactured by manual use of unidirectional prepregs. Four of the same woven layers were stacked together well aligned and cured under low and high pressure. Damage resistance was evaluated by subjecting 100 × 100 mm samples around impact energy levels where perforation took place using an instrumented impact test system. Results obtained showed that loose woven composites cured under low pressure were of higher perforation threshold compared to other combinations considered.