Ozen Engineering Inc.

Engineering, United States

Ozen Engineering Inc.

Engineering, United States

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Erdem Alaca B.,Koç University | Ozcan C.,Bogazici University | Ozcan C.,Ozen Engineering Inc. | Anlas G.,Bogazici University
Nanotechnology | Year: 2010

To address the necessity for a predictive computational tool for layout design in crack lithography, a tool for nanowire fabrication, a computational study is carried out using finite element analysis, where crack-free edge and crack-crack interactions are studied for various material combinations. While the first scenario addresses the ability to induce a controlled curvature in a nanowire, the latter provides an estimation of the minimum distance which can be kept between two straight nanowires. The computational study is accompanied by an experimental demonstration on Si/SiO2 multilayers. Finite element results are found to be well aligned with experimental observations and theoretical predictions. Stronger interaction is evident with a curved crack front modeling as well as with increasing first and decreasing second Dundurs' parameters. Therefore cracks can be packed closer with decreasing film stiffness. © 2010 IOP Publishing Ltd.


Grujicic M.,Clemson University | Sellappan V.,Clemson University | Sellappan V.,Ozen Engineering Inc. | Arakere G.,Clemson University | And 5 more authors.
Multidiscipline Modeling in Materials and Structures | Year: 2010

Purpose - The purpose of this paper is to propose and analyse computationally a new concept for mechanical interlocking between metal and plastics. The approach utilizes some of the ideas used in the spot-clinching joining process and is appropriately named "clinch-lock polymer metal hybrid (PMH) technology." Design/methodology/approach - A new approach, the so-called "direct-adhesion" PMH technology, is recently proposed Grujicic et al. to help meet the needs of automotive original equipment manufacturers and their suppliers for a cost-effective, robust, reliable PMH technology which can be used for the manufacturing of load-bearing body-in-white (BIW) components and which is compatible with the current BIW manufacturing-process chain. Within this approach, the necessary level of polymer-to-metal mechanical interconnectivity is attained through direct adhesion and mechanical interlocking. Findings - In an attempt to fully assess the potential of the clinch-lock approach for providing the required level of metal/polymer mechanical interlocking, a set of finite-element based sheet-metal forming, injection molding and structural mechanics analyses is carried out. The results obtained show that stiffness and buckling resistance levels can be attained which are comparable with those observed in the competing injection over-molding PMH process but with an ∼ 3 percent lower weight (of the polymer subcomponent) and without the need for holes and for over-molding of the free edges of the metal stamping. Originality/value - The paper presents a useful discussion of clinch-lock joining technology's potential for fabrication of PMH load-bearing BIW components. © Emerald Group Publishing Limited.


Grujicic M.,Clemson University | Arakere G.,Clemson University | Subramanian E.,Clemson University | Sellappan V.,Ozen Engineering Inc. | And 2 more authors.
Journal of Materials Engineering and Performance | Year: 2010

The problem of mechanical design, performance prediction (e.g., flap-wise/edge-wise bending stiffness, fatigue-controlled life, the extent of bending-to-torsion coupling), and material selection for a prototypical 1 MW horizontal-axis wind turbine (HAWT) blade is investigated using various computer-aided engineering tools. For example, a computer program was developed which can automatically generate both a geometrical model and a full finite-element input deck for a given single HAWT-blade with a given airfoil shape, size, and the type and position of the interior load-bearing longitudinal beam/shear-webs. In addition, composite-material laminate lay-up can be specified and varied in order to obtain a best combination of the blade aerodynamic efficiency and longevity. A simple procedure for HAWT-blade material selection is also developed which attempts to identify the optimal material candidates for a given set of functional requirements, longevity and low weight. © 2009 ASM International.


Grujicic M.,Clemson University | Xie X.,Clemson University | Arakere G.,Clemson University | Grujicic A.,Clemson University | And 2 more authors.
Journal of Materials Engineering and Performance | Year: 2010

The problem of optimal size, shape, and placement of a proximal radius-fracture fixation-plate is addressed computationally using a combined finite-element/design-optimization procedure. To expand the set of physiological loading conditions experienced by the implant during normal everyday activities of the patient, beyond those typically covered by the pre-clinical implant-evaluation testing procedures, the case of a wheel-chair push exertion is considered. Toward that end, a musculoskeletal multi-body inverse-dynamics analysis is carried out of a human propelling a wheelchair. The results obtained are used as input to a finite-element structural analysis for evaluation of the maximum stress and fatigue life of the parametrically defined implant design. While optimizing the design of the radius-fracture fixation-plate, realistic functional requirements pertaining to the attainment of the required level of the devise safety factor and longevity/lifecycle were considered. It is argued that the type of analyses employed in the present work should be: (a) used to complement the standard experimental pre-clinical implant-evaluation tests (the tests which normally include a limited number of daily-living physiological loading conditions and which rely on single pass/fail outcomes/decisions with respect to a set of lower-bound implant-performance criteria) and (b) integrated early in the implant design and material/manufacturing-route selection process. © 2010 ASM International.


Grujicic M.,Clemson University | Arakere G.,Clemson University | Pandurangan B.,Clemson University | Sellappan V.,Ozen Engineering Inc. | And 2 more authors.
Journal of Materials Engineering and Performance | Year: 2010

A multi-disciplinary design-optimization procedure has been introduced and used for the development of cost-effective glass-fiber reinforced epoxy-matrix composite 5 MW horizontal-axis wind-turbine (HAWT) blades. The turbine-blade cost-effectiveness has been defined using the cost of energy (CoE), i.e., a ratio of the three-blade HAWT rotor development/fabrication cost and the associated annual energy production. To assess the annual energy production as a function of the blade design and operating conditions, an aerodynamics-based computational analysis had to be employed. As far as the turbine blade cost is concerned, it is assessed for a given aerodynamic design by separately computing the blade mass and the associated blade-mass/size-dependent production cost. For each aerodynamic design analyzed, a structural finite element-based and a post-processing life-cycle assessment analyses were employed in order to determine a minimal blade mass which ensures that the functional requirements pertaining to the quasi-static strength of the blade, fatigue-controlled blade durability and blade stiffness are satisfied. To determine the turbine-blade production cost (for the currently prevailing fabrication process, the wet lay-up) available data regarding the industry manufacturing experience were combined with the attendant blade mass, surface area, and the duration of the assumed production run. The work clearly revealed the challenges associated with simultaneously satisfying the strength, durability and stiffness requirements while maintaining a high level of wind-energy capture efficiency and a lower production cost. © 2010 ASM International.


Wagner D.W.,Ozen Engineering Inc. | Divringi K.,Ozen Engineering Inc. | Ozcan C.,Ozen Engineering Inc. | Grujicic M.,Clemson University | And 2 more authors.
Multidiscipline Modeling in Materials and Structures | Year: 2010

Purpose - The aim of this paper is to present and evaluate a methodology for automatically constructing and applying the physiologically-realistic boundary/loading conditions for use in the structural finite element analysis of the femur during various exertion tasks (e.g. gait/walking). Design/methodology/approach - To obtain physiologically-realistic boundary/loading conditions needed in the femur structural finite element analysis, a whole-body musculoskeletal inverse dynamics analysis is carried out and the resulting muscle forces and joint reaction forces/moments extracted. Findings - The finite element results obtained are compared with their counterparts available in literature and it is found that the overall agreement is acceptable while the highly automated procedure for the finite element model generation developed in the present work made the analysis fairly easy and computationally highly efficient. Potential sources of errors in the current procedure have been identified and the measures for their mitigation recommended. Originality/value - The present approach enables a more accurate determination of the physiological loads experienced by the orthopedic implants which can be of great value to implant designers and orthopedic surgeons. © Emerald Group Publishing Limited.


Grujicic M.,Clemson University | Arakere G.,Clemson University | Xie X.,Clemson University | LaBerge M.,Clemson University | And 3 more authors.
Materials and Design | Year: 2010

The problem of size/thickness optimization of a distal femoral-fracture fixation-plate is addressed computationally using a combined finite-element/design-optimization procedure. To obtain realistic physiological loading conditions associated with normal living activities (cycling, in the present case), a musculoskeletal multi-body inverse-dynamics analysis is carried out of a human riding the bicycle. While optimizing the design of the femoral-fracture locking-plate, realistic functional requirements pertaining to attain the required level of fracture-femur fixation and longevity/lifecycle were used. It is argued that these types of analysis should be used to complement pre-clinical implant-evaluation tests, the tests which normally include a limited number of physiological loading conditions and single pass/fail outcomes/decisions with respect to a set of lower-bound implant-performance criteria. © 2010 Elsevier Ltd.


Methods and computer readable media for designing an implant to support a bone of a person. Based on the daily activities of the person, one or more musculoskeletal loads applied to the bone are determined. Also, a set of characteristics of the implant, such as dimension, material, geometry, and shape of the implant, is selected. Then, a numerical simulation of the implant and the bone is performed to determine a physical status of the implant under the musculoskeletal loads. Subsequently, it is determined if the physical status meets one or more of preset failure conditions. If the determination is negative, the implant is taken as an optimized implant. Otherwise, at least one of the characteristics of the implant is modified and numerical simulation of the implant and the bone is repeated until an optimized implant is obtained.

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