Changes in the structure and digestion fractions of wheat starch cooked with and without fiber

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2021-1-27

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Gürsoy, Bahadır

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Spacecraft are exposed to severe mechanical loads, including random and periodical vibration, acoustic loads, sinusoidal shock, and pyroshock during their trip to orbit. Such loads usually develop due to a separation event through the activation of pyrotechnic devices and might be transmitted throughout the entire structure and seriously affect electronics components' service performance. It is crucial to study whether the instruments would resist such a harsh environment. Different instruments are validated with various experimental setups, most of which are openloop systems. Therefore, due to the vulnerability and high cost of the space instruments, the designed experimental setups should be calibrated with dummy equipment to ensure the desired shock level is applied, which takes considerable time and effort. In this context, the current study investigates the potential of the explicit finite element method in designing a ringing plate pyroshock test system and the phase of calibration tests. In order to realize this, a set of preliminary finite element simulations are performed, and the design process of the ringing plate test system is presented. Various experiments are conducted with the designed and manufactured test bench. The obtained Shock Response Spectrum (SRS) responses are fitted to the explicit finite element simulations, which show good agreement after sensitivity analysis. Then the simulations are repeated with the dummy instrument using the fitted parameters, and the potential of the numerical approach to predict a realistic response is discussed.

Subject Keywords

Pyroshock, Mechanical excitation, Impact loading, Explicit finite element analysis, SRS curve

URI

https://hdl.handle.net/11511/89702

Collections

Graduate School of Natural and Applied Sciences, Thesis

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Citation Formats

B. Gürsoy, “Changes in the structure and digestion fractions of wheat starch cooked with and without fiber,” M.S. - Master of Science, Middle East Technical University, 2021.