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

Download
2021-1-27
Gürsoy, Bahadır
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.

Suggestions

Development of structural optimization and neural network design tool for buckling behaviour of skin stringer structures under combined compression and shear loading
Okul, Aydın; Gürses, Ercan; Department of Aerospace Engineering (2019)
Stiffened panels are commonly used in aircraft structures in order to resist high compression and shear forces with minimum total weight. Minimization of the weight is obtained by combining the optimum design parameters. The skin panel dimensions, the stringer spacing and the stringer dimensions are some of the critical parameters which affect the global buckling behaviour of the stiffened panel. The aim of this thesis is to develop a neural network design tool and to carry out a geometric optimization for ...
Computer aided engineering of an unmanned underwater vehicle
Cevheri, Necmettin; Aksel, Mehmet Haluk; Department of Mechanical Engineering (2009)
Hydrodynamic and thermal analyses performed during the conceptual design of an unmanned underwater vehicle are presented in this study. The hull shape is determined by considering alternative shapes and the dimensions are determined from the internal arrangement of components. Preliminary thermal analyses of the watertight section are performed with a commercial software called FLUENT to check the risk of over-heating due to the heat dissipation of devices. Performance of the proposed hull design is analyze...
Effects of inflow boundary layer on the wake of a radially non-uniform porous disk
Abdulrahim, Anas; Akpolat, M. Tuğrul; Hassanein, Abdelrahman; Perçin, Mustafa; Uzol, Oğuz (2021-05-01)
This study presents the results of an experimental investigation focusing on the effects of the inflow boundary layer on the wake characteristics of a 0.12 m diameter porous disk with radially non-uniform porosity in terms of mean flow, turbulence, and wake scaling. Two-dimensional two-component particle image velocimetry measurements within the wake are performed up to 7.5 diameters downstream as the disk is lowered deeper into a boundary layer that is representative of a neutral atmospheric boundary layer...
Modeling and experimental verification of dynamic characteristics antenna structure under mechanical shock using MDOF model
Özçelik, Yunus Emre; Ciğeroğlu, Ender; Çalışkan, Mehmet; Department of Mechanical Engineering (2015)
Antenna structures used in electronic warfare, radar, naval, satellite, spacecraft systems encounter mechanical shock from various sources such as near miss under water explosion, pyrotechnic and ballistic shocks. Since most antenna structures have larger dimension in longitudinal direction and experience high requency, high amplitude shock energy, geometric nonlinearity becomes crucial to predict dynamic behavior in real life. In this thesis, an antenna structure is modeled by Euler-Bernoulli beam theory i...
Development of Structural Neural Network Design Tool for Buckling Behaviour of Skin-Stringer Structures Under Combined Compression and Shear Loading
Okul, Aydın; Gürses, Ercan (2018-11-15)
Stiffened panels are commonly used in aircraft structures in order to resist high compression and shear forces with minimum total weight. Minimization of the weight is obtained by combining the optimum design parameters. The panel length, the stringer spacing, the skin thickness, the stringer section type and the stringer dimensions are some of the critical parameters which affect the global buckling allowable of the stiffened panel. The aim of this study is to develop a design tool and carry out a geometri...
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.