Atila Ertas

Transformation of higher education: the transdisciplinary approach in engineering

Educational programs face many difficulties because of the rapid change of technology in todays environment. The potential for educational programs based on the transdisciplinary model is discussed in order to address and overcome these difficulties. A closer relationship with industry in developing educational programs is suggested. Finally, a new transdisciplinary master of engineering program, developed jointly by industry and the Institute for Design and Advanced Technology at Texas Tech University, is described.

Life-cycle engineering: Issues, tools and research

Life-cycle engineering (LCE) is a decision-making methodology that considers performance, environmental and cost requirements for the duration of a product. This methodology is becoming a norm for global companies that want to remain competitive. To facilitate and enhance the application of LCE methodology to industrial products, a number of computer tools or utilities that require minimal user input, and hence run automatically in the background of the design process, have been developed. These utilities are intended to provide a feedback on an evolving design without impeding or hampering the design process. There exists a need to continue research on the development of tools that simulate flows in a life-cycle and optimize them. These tools should be based on the client-server model base on the Internet to facilitate the e-Transition.

The Transdisciplinary Product Development Lifecycle model

Abstract In this paper, a new product development lifecycle model, the Transdisciplinary Product Development Lifecycle (TPDL) model, is explained. This new model is based on the axiomatic design (AD) method developed by Suh; hence it inherits the benefits of applying AD to product development. In this model, the AD method is extended to cover the whole product development lifecycle, including the test domain, and new domain characteristic vectors are introduced to systematically capture and manage the input constraints and system components. The TPDL model helps develop, capture, and present both the big-picture and a detailed view of the product development knowledge, including design and requirement traceability knowledge. The objectives of the TDPL model are to guide the designers, developers, and other members of a transdisciplinary product development team throughout the development effort as well as to help capture, maintain, and manage the knowledge produced during the product development process. The TDPL model aims to improve the quality of the design, requirements management, change management, project management, and communication between stakeholders as well as to shorten the development time and reduce the development cost.

Performance of an anisotropic Allman/DKT 3-node thin triangular flat shell element☆

Abstract A simple, explicit formulation of the stiffness matrix for an anisotropic, 3-node, thin triangular flat shell element in global coordinates is presented. An Allman triangle (AT) is used for membrane stiffness. The membrane stiffness matrix is explicitly derived by applying an Allman transformation to a Felippa 6-node linear strain triangle (LST). Bending stiffness is incorporated by the use of a discrete Kirchhoff triangle (DKT) bending element. Stiffness terms resulting from anisotropic membrane-bending coupling are included by integrating, in area coordinates, the membrane and bending strain-displacement matrices. Using the aforementioned approach, the objective of this study is to develop and test the performance of a practical 3-node flat shell element that could be used in plate problems with unsymmetrically stacked composite laminates. The performance of the latter element is tested on plates of varying aspect ratios. The developed 3-node shell element should simplify the programming task and have the potential of reducing the computational time.

Sharing information and data across heterogeneous e-health systems

Information and data sharing across heterogeneous e-health systems, focusing on the management of patient care, have become the backbone of modern delivery of sustainable telemedicine services. Information and data available to healthcare practitioners in such environments range from patients medical records, stored in repositories at places where patients have been treated, to a variety of information related to medical research, pharmaceutical products, or information stored within social networks of healthcare interest groups. This study sought to demonstrate two different approaches enabling the sharing of information/data across heterogeneous e-health systems: (1) Context-Aware Data Retrieval Architecture (CADRA), which secures the extraction and presentation of e-health information to users in requested format, and (2) Generic Ontology for Context Aware, Interoperable, and Data Sharing (Go-CID) software applications, which secure semantic interoperation across heterogeneous e-health data sources. Proof-of-concept was demonstrated in both cases, CADRA and Go-CID, to achieve understanding and building of knowledge about e-health environments. This study invites practical solutions for interoperable e-health systems.

Experimental Investigation of Galling Resistance in OCTG Connections

The results of galling experiments are strongly dependent on the method used and vary from test machine to test machine. However, by a well-developed test method and testing machine, one can obtain reliable and repeatable results. The primary objective of this research is to develop a new test method and machine for evaluating galling resistance in OCTG (oil country tubular goods) connections. Through the application of basic principles of statistical design of experiments, the galling resistance in OCTG threaded connections has been investigated. For estimating the nominal failure stress, two statistical methods, namely, up-and-down and frequency distribution, have been applied and compared. Galling resistance, one of the most important design factors of OCTG connections, has been studied and discussed.

Effect of damping and wave parameters on offshore structure under random excitation

This paper describes the linearized and nonlinear dynamic response of a tension leg platform (TLP) to random waves and current forces. The forcing term of the equation of motion is inherently nonlinear due to the nonlinear drag force. Two analysis procedures are used: nonlinear time domain analysis and linear frequency domain analysis. For the nonlinear analysis, the random wave particle velocities and accelerations are simulated for a given wave spectrum. The nonlinear equation of motion is then integrated directly to obtain the system response statistics. For the linear frequency domain analysis, the nonlinear drag force is linearized through an introduction of linearization coefficients. The main objective of this paper is to investigate the effect of the structural damping and wave parameters on both nonlinear and linear dynamic response of the TLP by parametric studies. The results of stochastic nonlinear and linear dynamic response of the TLP, with and without the presence of current, are presented and compared.

The Use of Re-Refined Oil in Vehicle Fleets

A literature search to identify deleterious effects of using re-refined oil did not disclose any validated occurrences. Significant engine testing using re-refined lubricating oil is reported and no cases were discovered in which engine operation was affected negatively by the use of re-refined oil. The American Petroleum Institute (AFT) allows the use of re-refined base stock oils in the blending of end use lubricants. Based on oil sample testing performed in this research as well as other authoritative sources, it was determined that no significant chemical or physical differences exist between rerefined and virgin oils. Differences noted in this research were related to higher levels of polynuclear aromatics (PNA’s) in the re-refined oil. PNA’s are formed due to the extreme conditions of temperature and pressure during operation of an internal combustion engine. PNA components are essentially removed by the hydrogenation process during re-refining ahd the trace amounts detected in new re-refined oil do not affect the oil’s physical performance characteristics. Similar levels of PNA’s were detected in used re-refined and used virgin oil, thereby indicating that the chemical change during use in an internal combustion engine is independent of the oil used. Lubricating fluid logistics and handling procedures were studied and recommendations related to the screening of suppliers and the use of purchasing specifications to insure the procurement of only qualified supplier’s products are presented. Purchasing specifications are generally acceptable but specific requirements must be stringently enforced to ensure that only quality lubricating products are purchased. Alternative contracting arrangements that offer lubricating fluid procurement and disposal cost savings are suggested. Suppliers have indicated interest in determining cost-effective approachs for supplying lubricants and collecting/disposing of used fluids. Although this research was performed for the Texas Department of Transportation (TxDOT) the recommendations presented are appropriate for other vehicle fleet operators.

Response Statistics of a Beam-Mass Oscillator Under Combined Harmonic and Random Excitation

In the present study, the response statistics of a beam-mass oscillator under combined harmonic and random excitation were investigated. The Gaussian and non-Gaussian closure schemes, in conjunction with the stochastic averaging method, were used to solve for the mean square response. The influence of the oscillator parameters on the response statistics was studied. The harmonic component of the excitation was observed to manifest itself, as an oscillation, in the steady-state mean square response. Results obtained showed that the non-Gaussian solution yields higher steady-state mean square responses than those obtained from the Gaussian solution. It was further shown that the harmonic time-varying properties of the oscillator are preserved by omitting the time-averaging in the stochastic averaging procedure.

Analysis of Free Pendulum Vibration Absorber Using Flexible Multi-Body Dynamics

Structures which are commonly used in our infrastructures are becoming lighter with progress in material science. These structures due to their light weight and low stiffness have shown potential problem of wind-induced vibrations, a direct outcome of which is fatigue failure. In particular, if the structure is long and flexible, failure by fatigue will be inevitable if not designed properly. The main objective of this paper is to perform theoretical analysis for a novel free pendulum device as a passive vibration absorber. In this paper, the beam-tip mass-free pendulum structure is treated as a flexible multibody dynamic system and the ANCF formulation is used to demonstrate the coupled nonlinear dynamics of a large deflection of a beam with an appendage consisting of a mass-ball system. It is also aimed at showing the complete energy transfer between two modes occurring when the beam frequency is twice the ball frequency, which is known as autoparametric vibration absorption. Results are discussed and compared with findings of MSC ADAMS. This novel free pendulum device is practical and feasible passive vibration absorber in the mitigation of large amplitude wind-induced vibrations in traffic signal structures.