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Article Citation - WoS: 5Citation - Scopus: 8Biological System Analysis in Bioinspired Conceptual Design (bicd) for Bioinspired Robots(Romanian Soc Control Tech informatics, 2011) Eroglu, Aylin Konez; Eroğlu, Aylin Konez; Erden, Zuhal; Erden, Zühal; Erden, Abdulkadir; Erden, Abdulkadir; Eroğlu, Aylin Konez; Erden, Zühal; Erden, Abdulkadir; Department of Mechatronics Engineering; Department of Mechatronics Engineering; Mechatronics Engineering; Mechatronics Engineering; Department of Mechatronics Engineering; Mechatronics EngineeringBioinspired design (BID) provides a systematic way for bioinspired applications. Although several BID approaches as well as some tools and databases are available in the literature, the studies on BID are still challenging for designers and/or engineers because of limitations of current BID approaches. There are mainly two directions related with these limitations. One of them is the representation of knowledge on biological systems and the second is the problem of transforming this knowledge into engineering domain. These limitations expose two questions; firstly, "What knowledge is required to describe biological systems?" and "How this knowledge is represented?" and secondly, "How this knowledge is transformed into the engineering domain?". This paper presents a study which aims to answer the first question about knowledge required to represent biological systems. This knowledge is obtained during "Analysis of Biological Systems" stage of a new suggested bioinspired conceptual design (BICD) procedure.Article Citation - WoS: 64Citation - Scopus: 69A Semi-Empirical Approach for Residual Stresses in Electric Discharge Machining (edm)(Elsevier Sci Ltd, 2006) Ekmekci, Bulent; Tekkaya, A. Erman; Erden, AbdulkadirHigh residual stresses are developed on the surfaces of electric discharge machined parts. In this study, layer removal method is used to measure the residual stress profile as a function of depth beneath the surface caused by die sinking type EDM. Cracking and its consequences on residual stresses are also studied on samples machined at long pulse durations. A modified empirical equation is developed for scaling residual stresses in machined surfaces with respect to operating conditions. In this model, a unit amplitude shape function representing change in curvature with respect to removal depth is proposed. The proposed form is found to be a special form of a Gauss Distribution. It is the sum of two Gaussian peaks, with the same amplitude and pulse width but opposite center location. The form can be represented by three constant coefficients. These coefficients depend on the released energy by a power function. (C) 2005 Elsevier Ltd. All rights reserved.Article Citation - WoS: 36Citation - Scopus: 42Geometry and Surface Damage in Micro Electrical Discharge Machining of Micro-Holes(Iop Publishing Ltd, 2009) Ekmekci, Buelent; Sayar, Atakan; Opoz, Tahsin Tecelli; Erden, AbdulkadirGeometry and subsurface damage of blind micro-holes produced by micro electrical discharge machining (micro-EDM) is investigated experimentally to explore the relational dependence with respect to pulse energy. For this purpose, micro-holes are machined with various pulse energies on plastic mold steel samples using a tungsten carbide tool electrode and a hydrocarbon-based dielectric liquid. Variations in the micro-hole geometry, micro-hole depth and over-cut in micro-hole diameter are measured. Then, unconventional etching agents are applied on the cross sections to examine micro structural alterations within the substrate. It is observed that the heat-damaged segment is composed of three distinctive layers, which have relatively high thicknesses and vary noticeably with respect to the drilling depth. Crack formation is identified on some sections of the micro-holes even by utilizing low pulse energies during machining. It is concluded that the cracking mechanism is different from cracks encountered on the surfaces when machining is performed by using the conventional EDM process. Moreover, an electrically conductive bridge between work material and debris particles is possible at the end tip during machining which leads to electric discharges between the piled segments of debris particles and the tool electrode during discharging.Conference Object Citation - WoS: 2Citation - Scopus: 4CHARACTERISTICS OF SURFACE DAMAGE IN MICRO ELECTRIC DISCHARGE MAChinING OF MICRO HOLES(Trans Tech Publications Ltd, 2010) Ekmekci, Buelent; Sayar, Atakan; Opoz, T. Tecelli; Erden, AbdulkadirMicro Electric Discharge Machining is mostly used micromachining technique for manufacturing of micro holes and mini cavities. It is a thermal material removal process achieved by application of recursive electrical sparks between two conductive materials immersed in dielectric liquid. There are many electrical and technological parameters, which are effective in the machining characteristics and machined material surface integrity. In this study, effects of pulse energy on characteristics of surface damage in micro electric discharge machining of micro holes are investigated. To observe the influences of investigated pulse forms, a series of micro-holes were machined and cut from cross sections for metallurgical examinations. Unconventional etching agents were applied to examine the metallurgical transformations using optical and scanning electron microscopy. It was observed that heat-damaged segment is composed of three distinctive layers, have relatively high thicknesses (0.2 to 10 mu m) when compared with the size of the micro holes and varies noticeably with respect to drilling dept. Different morphological structures and deformations in the subsurface of micro-hole walls at several sections were illustrated. Finally, analyzed machining parameters and variation of hat damaged layer thicknesses were discussed in terms of drilling depth.Article Citation - WoS: 27An Experimental Study on the Geometry of Microholes in Microelectric Discharge Machining(Taylor & Francis inc, 2009) Opoz, Tahsin Tecelli; Ekmekci, Buelent; Erden, AbdulkadirShape and dimensional geometry of blind microholes produced by microelectric discharge machining (micro-EDM) is investigated experimentally to explore the relational dependency with respect to machining time. For this purpose, microholes are machined with machining times ranging from 1-80min on plastic mold steel samples using tungsten carbide tool electrode and hydro carbide dielectric liquid composed of mineral and synthetic oils. All other operational machining parameters such as pulse time, gap voltage, average current, and so forth, are kept constant during machining. Depth, diametric expansions, end-tip shape, wall side parallelisms of holes were analyzed both on surface and cross-sections of the samples. Consequently, nine different end-tip shape formations were observed, and these shapes discussed on basis of dielectric liquid circulation and sparking conditions during machining. Enlargement in hole diameter was predicted by defining a band-width of 20 mu m hole expansion. Moreover, parallel wall-side length was expressed as the microhole depth where 5% reduction in entrance diameter was measured at the tapered section.Conference Object Citation - WoS: 1BIOINSPIRED CONCEPTUAL DESIGN (BICD): CONCEPTUAL DESIGN OF A GRASSHOPPER-LIKE JUMPING MECHANISM AS A CASE STUDY(design Soc, 2011) Eroglu, Aylin Konez; Erden, Zuhal; Erden, AbdulkadirThe evolution process of nature creates highly effective, power efficient, and perfectly structured biological systems. These excellent systems provide an inexhaustible source for engineers and scientists who desire to inspire ideas, processes, structures, functions, and behaviors from biological domain and implement them into engineering domain. This approach is called "Bioinspired" and challenging for engineers. However, some problems of the practical approaches are observed. One of the problems is "ad hoc" nature of the process. Each bioinspired design product has resulted in a differing design process and a generalization was not possible. Another problem rises due to the terminology difference between engineers and biologists. To overcome these problems, a need for a systematic bioinspired design (BID) process was realized in early 2000s and since then, considerable research on the BID methodology has been progressed. Within the context of BID, this paper introduces a new approach on bioinspired conceptual design (BICD) procedure for hybrid bioinspired robots which can be inspired from multiple biological systems. An illustrative case study is given in the paper.
