Response of filled corrugated sandwich structures to shock loading at high temperatures

Payam Fahr, University of Rhode Island

Abstract

The dynamic response of filled corrugated steel sandwich panels was investigated under combined extremes of blast loading and high temperature heating. The objective of this project was to study blast mitigation and the thermo-mechanical response of panels using a polymer based syntactic foam and mortar as a filler material. These materials were selected due to their thermal resistivity. In this study, silicone resin (with an operating temperature range between -53°C to 232°C) and two types of glass bubbles were selected as materials to develop a heat resistive syntactic foam. The mechanical properties of the foam were investigated, in ambient temperatures, before and after high-temperature heat treatment (of 500°C), by quasi-static compression experiments. It was observed that plateau stress increases after introduction of glass bubbles in silicone, enhancing the energy absorption properties for both specimens with and without heat treatment. To produce repeatable blast loading, a shock tube was utilized. Pressure history was recorded using pressure transducers located in the shock tube muzzle. High speed photo-optical methods utilizing Digital Image Correlation (DIC) coupled with optical band-pass filters and high-intensity light source, were utilized to obtain the real-time deformation at high temperature while a third camera captured side-view deformation images. The shock pressure profiles and DIC 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. Shock tube experiments were performed to investigate the blast response of corrugated steel sandwich panels filled with a silicone based syntactic foam filler at room and high temperature. 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, compared to an empty panel. The highest impulse was imparted on the specimen at room temperature and subsequently lower impulses with increasing temperature. Due to increasing ductility in steel with high temperature, the specimens demonstrated an increase in back face deflection, in-plane strain and out-of-plane velocity with increasing temperatures with weld failure being the primary form of core damage. High temperature blast experiments were also performed on mortar filled corrugated steel sandwich panels. Mortar is a common building material that can withstand extreme temperatures. It was observed cement based mortars are thermally resilient enough to be used as a filler material for high temperature applications. The highest impulse was imparted on the specimen at room temperature and subsequently lower impulses with increasing temperature. A temperature difference of at least 300ºC was observed across the thickness of the specimen for all heating conditions. Due to increasing ductility in steel with high temperature, the specimens demonstrated an increase in back face deflection, in-plane strain and out-of-plane velocity with increasing temperatures with weld failure being the primary form of core damage.^

Subject Area

Engineering, Mechanical

Recommended Citation

Payam Fahr, "Response of filled corrugated sandwich structures to shock loading at high temperatures" (2014). Dissertations and Master's Theses (Campus Access). Paper AAI1555644.
http://digitalcommons.uri.edu/dissertations/AAI1555644

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