Browsing by Author "Fahr, Payam"
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Item Development of a polymer based syntactic foam for high temperature applications(Polish Acad Sciences Inst Physics, 2014-02) Fahr, Payam; Shukla, Arun; Yazıcı, Murat; Güneş, Serap; Akay, Sertan Kemal; Uludağ Üniversitesi/Mühendislik Fakültesi/Otomotiv Mühendisliği Bölümü.; Uludağ Üniversitesi/Fen Edebiyat Fakültesi/Fizik Bölümü.; 0000-0002-8720-7594; M-4741-2017; R-7260-2016; 7007162323; 8912603900; 24801954600Syntactic foams are one of the most widely used close cell structured foams. They are used in applications for naval, aeronautical, aerospace, civil, industrial, and automotive engineering due to good acoustical attenuation, excellent strength to weight ratio, vibration isolation, and dielectric properties. These foams are fabricated by incorporation of hollow particles in a matrix material. The most preferred matrix materials are polymers. In this study silicone resin (useful temperature range -53 degrees C to 232 degrees C) was selected as a binder material. Glass bubbles were incorporated into the silicone resin at three different mass percentages (10%, 20%, and 30%). The density of the silicone was reduced more than 50% by 30% glass bubble contribution. The foam mechanical properties were investigated in a room temperature and after heat treatment at 500 C by quasi-static compression experiments. Microstructural transitions by the temperature raises were examined by using scanning electron microscopy pictures. It was observed that the increase of glass bubble percentage in silicone rubber enhanced the energy absorption properties in the heat treated and room temperature specimens. Plateau stress and densification amount were improved under quasi-static compression load by the glass bubble percentage increase. It can be said that developed syntactic foams can be used in heat resistant, low weight and high compression strength exigencies.Item Shock response of filled corrugated sandwich structures under extreme temperatures(Sage Puplications, 2018-01) Fahr, Payam; Shukla, Arun; Yazıcı, Murat; Uludağ Üniversitesi/Mühendislik Fakültesi/Otomotiv Mühendisliği Bölümü.; 0000-0002-8720-7594; M-4741-2017; 7007162323Shock tube experiments were performed to investigate the blast response of corrugated steel cellular core sandwich panels filled with a silicone based syntactic foam at room and high temperatures. The syntactic foam filler was prepared by mixing a two-part silicone mixture with glass microspheres; its microstructure, and mechanical properties were also characterized. The syntactic foam-filled sandwich panels were loaded via air shock pressure by using the shock tube with a fixture capable of testing materials at temperatures up to 900?. High-speed photo-optical methods, digital image correlation techniques, were used in tandem with optical band-pass filters and high intensity light sources for providing sufficient contrast at elevated temperatures. Back-face deformation images were captured using two synchronized high-speed cameras while a third camera captured the side view deformation images. The shock pressure profiles and digital image correlation analysis were used to obtain the impulse imparted to the specimen, transient deflection, in-plane strain and out-of-plane velocity of the back-face sheet. It was observed that using the syntactic foam as a filler material decreased the front face and back face deflections by 42% and 27%, respectively, as compared to the empty sandwich panel. At high temperatures, the silicone-based syntactic foam decomposes into silica, a stable and non-hazardous byproduct. The highest impulse was imparted to the specimen at room temperature and subsequently lower impulses with increasing temperatures were observed. Due to the increased ductility of steel at high temperatures, the specimens demonstrated an increase in back face deflection, in-plane strain and out-of-plane velocity with increased temperatures, with weld failure being the primary form of core damage.