Murat Yavuz Solmaz

In this study, the rheological properties of shear thickening fluid, which are generally used as single solid phase in the literature, were investigated by chemical material reinforcement. Considering that the unique shear thickening effect of STF is used in many areas such as increasing the impact resistance of fabrics and energy dissipation, this study aims to provide guidance for investigating what STFs can do with chemical bonds as well as physical bonding.Methylene diphenyl diisocyanate (MDI) was used in varying proportions for chemical reinforcement. When the rheological properties of the suspensions reinforced with MDI as a chemical additive were evaluated, the initial viscosity values increased as the MDI ratio increased, while the solidification behavior under shear was observed significantly in the sample with 2.5% MDI ratio with increasing shear ratio.

The effect of different joint angles and joint types in adhesively bonded joints was investigated. Two joint types were chosen to examine the effect of the joint type. A total of 12 samples were produced at six different angles (30°, 45°, 52°, 60°, 75°, and 90°) to examine the effect of joint angle on the scarf and double butt–lap joint types. St 37 steel was used as the adherend material. The adhesion distance, sample thickness, and adhesion area were kept constant in the samples. There were differences in the sample widths to make the angle change by keeping the adhesive bonding length constant. 3M Scotch-Weld DP810 epoxy adhesive was used as the adhesive. The adhesive thickness was chosen as 0.1 mm. An axial tensile load was applied to the samples, and the results were recorded and evaluated. When scarf and double butt–lap joint samples are compared with each other according to their angles, it was seen that double butt–lap joints were more successful in samples with 30, 45, and 52° joint angles, and scarf lap joints were more successful in samples with 60, 75, and 90° joint angles.

This study experimentally investigated the flexural fatigue behaviors of honeycomb sandwich composites subjected to low velocity impact damage by considering the type and thickness of the face sheet material, the cell size and the core height parameters. Carbon-fiber reinforced composite and the aluminum alloy was used as the face sheet material. First, the static strength of undamaged and damaged specimens was determined by three-point bending loads. Secondly, the fatigue behaviors of the damaged and undamaged specimens were determined. Low velocity impact damage decreased the flexural strength and fatigue lives but increased the damping ratio for all specimens. Maximum damping ratio values were observed on specimens with a aluminum face sheet.

In the research for this contribution, the use of layered hybrid composites as materials for ballistic armor has been tested. As part of the study, ballistic tests of glass/aramid/carbon fiber laminated comp osite plates at different reinforcing angles, in various numbers and thicknesses were carried out and the results analyzed. Eight hybrid composite laminates, of various thicknesses 200 × 200 mm in size were produced by the hand lay-up method at angles of 0°, +/−45°. Plain and twill fabrics were used to analyze the ballistic performances at various fiber reinforcing angles. Ballistic tests were carried out at the Elazig Special Operation Branch Office, using a Beretta gun loaded with 9 mm FMJ (full metal jacket) bullets. These experiments with ballistic test equipment were conducted in accordance with international standards. During the ballistic experiments, the velocity and BFS (backface signature) was measured and evaluated. Test results suggest that five samples were successful according to NIJ 0101-06 standards. It was found that twill woven (TW) fabrics made for the study manifest a higher ballistic performance than plain-woven (PW) fabrics. UD (unidirectional), +/−45° UD fabrics were found to be more effective than 0° UD fabrics. The findings are indicative for the design of lightweight ballistic armor material.

Dundar S, et al. J Korean Assoc Oral Maxillofac Surg. 2019 Apr;45(2):91-96. https://doi.org/10.5125/jkaoms.2019.45.2.91

The purpose of this study was to investigate numerically the effects of the inclination (collodiaphyseal) angle and bone cement (polymethylmethacrylate) filling on the stress distribution of human femurs and implants after the implementation of a partial endoprotez arthroplasty. Ti6Al4V, which is the most commonly used implant material, was choosen for this study. In the numerical study, solid models of implants and femurs were created using the SolidWorks 2010 package program, then stress analyses were carried out at five different inclination angles, 120°, 125°, 130°, 135° and 140°, with and without bone cement (polymethylmethacrylate), using the ANSYS Workbench 12.0 package program. The anteversion angle was assumed to be 12.5° for all models. As a result of the increase in the inclination angle and the addition of bone cement, it was determined that the stress values of the femurs and implants were reduced. Within the limitations of this study it has been shown that parameters like bone cement, anteversion angle, and an appropriate inclination angle should be tested previous to partial endoprosthesis arthroplasty surgery necessary as a result of damage to the human femur.