Wyniki wyszukiwania - BazTech

Ograniczanie wyników

2 Archives of Civil and Mechanical Engineering

2 2023

Powiadomienia systemowe

Sesja wygasła!

Znaleziono wyników: 2

Liczba wyników na stronie

Wyniki wyszukiwania

Sortuj według:

Ogranicz wyniki do:

Deceleration behavior of multi‑layer cork composites intercalated with a non‑Newtonian material

Sheikhi Mohammad Rauf, Gürgen Selim

Archives of Civil and Mechanical Engineering

2023

Vol. 23, no. 1

art. no. e2, 2023

Impact or sudden accelerations are strictly avoided by sensitive systems such as electronic devices, robotic structures and unmanned aerial vehicles (UAVs). In order to protect these systems, various composites have been developed in recent years. Due to its excellent energy absorbing capabilities as well as eco-friendly and sustainable properties, cork is one of promising materials dedicated to protective applications. In this study, we beneft from cork agglomerates in multi-layer design considering its advantages such as high fexural stifnesstoweight ratio and good buckling resistance over monolithic structures. In addition, a non-Newtonian material, namely shear thickening fuid (STF) was incorporated in this design. STF shows rapid increase in its viscosity under loading and thereby enabling a stifer texture that contributes to protective performance. At rest state, STF exhibit fuidic behavior and provides fexibility for composite. In the experimental stage, deceleration behavior of these composites was investigated. According to the analyses, STF exhibits promising results to lower peak decelerations while extending time period of deceleration under impact loading. STF contribution is pronounced by using this material in a closed medium such as in wrapped foam to avoid spilling out of composite during impact. The designed eco-friendly smart composites are suggested to cover internal parts in sensitive systems. Micro-mobility helmet is another prospective application area for cork/STF structures since they provide light-weight, excellent fexibility and good deceleration behavior.

Anti‑impact and vibration‑damping design of cork‑based sandwich structures for low‑speed aerial vehicles

Sheikhi Mohammad Rauf, Gürgen Selim, Altuntas Onder, Sofuoğlu Mehmet Alper

Archives of Civil and Mechanical Engineering

2023

Vol. 23, no. 2

art. no. e71, 2023

Nowadays, lightweight and eco-friendly composites with improved mechanical properties are highly interesting. Sandwich-structured composites are a type of high-performance structural composite that is lightweight with a high strength-to-weight ratio and excellent specifc energy absorption capabilities. In this study, cork-based sandwich structures resistant to impact and vibrations were designed and produced for the possibility of being used in the protective structures of low-speed aerial vehicles. To identify and match the best combination of different face sheets with a cork core, first, aramid fabric-reinforced polymer (AFRP), carbon fiber-reinforced polymer (CFRP), and glass fiber-reinforced polymer (GFRP) face-sheet composites were produced using the compression molding method (prepreg layup). Then, sandwich structures consisting of AFRP, CFRP, GFRP, and aluminum face sheets with a fixed core layer of cork were designed and assembled. Since the design goal of these structures is to use them in low-speed aerial vehicles, impact deceleration and vibration tests were applied to face sheets and sandwich structures individually, which are the most important factors involved in these structures during fight, particularly in rotary-wing drone applications. A low-energy drop-tower system was used for the calculation of deceleration results. Besides, the vibration properties of the structures were investigated using the modal analysis method and based on the natural frequency responses of the tested face sheets and sandwich structures, damping ratios and structural stiffness were measured. According to the results, compared to other face sheets, CFRP showed better resistance along with the cork core, when the structure was exposed to impact and vibration threats. This study provides useful information on cork core sandwich structures for academic and industrial researchers in choosing the right face sheet.