bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Framework for Sufficiency Estimation of Engineering Design Models
Authors: Radhakrishnan Rajesh , McAdams Daniel A. 
Published: November 2020

Abstract
Engineering design models are aids that provide the designer with the ability to visualize the form and predict the nature and behavior of any product. In each stage of design, these models are used to predict the result of, or guide, design specifications, at a time when the design can still be changed with minimal negative impact. To ensure the downstream validity of these specifications or decisions, the designer must construct models that have sufficient accuracy and resolution.
Determining the goodness of a model for a particular design decision or specification is a fundamental and pervasive question in engineering. Though fast to construct, and generally inexpensive, models based on estimation and approximation may not provide information of sufficient quality to make an accurate evaluation. In contrast, the crispness and depth of information gained from detailed computational analysis or experimental trials may come at too great an expense.
Hence, a key aspect of model construction in design is deciding whether a model is appropriate for a particular design specification or evaluation considering accuracy and cost factors. This paper explores the application of utility theory to the model construction problem. We also discuss how estimated model accuracy affects the confidence of selecting a particular model. We present this research through application to a racecar sway bar.
A Class of Forms From Function: The Case of Parts Moving in Contact
Authors: Ilieş Horea T. , Shapiro Vadim 
Published: November 2020

Abstract
We consider the general problem of designing mechanical parts moving in contact under the influence of externally applied loads. Geometrically, the problem may be characterized in terms of a conjugate triplet which is formed by the two shapes moving in contact and their relative motion. We show that every such triplet belongs to at least two classes of functionally equivalent designs that may be represented uniquely by maximal triplets, corresponding respectively to the two largest contact shapes that are guaranteed to contain all other possible solutions to the contact design problem.
In practical terms, the proposed characterization of the contact problem enables the systematic exploration of the design space using fully defined representatives of the functionally equivalent class of parts. Furthermore, such exploration may be performed using standard tools from geometric modeling, and without assuming any particular parametrization that necessarily restrict both the design space and possible computational techniques for exploring feasible designs. Because it supports generation of an essentially unlimited space of design solutions for a given contact problem, the proposed approach is particularly effective at the conceptual design stage.
Orchestrating Learning in a Graduate Engineering Design Course
Authors: Chamberlain Matthew K. , Williams Christopher B. , Cowan F. Scott , Mistree Farrokh 
Published: November 2020

Abstract
ME6101: Engineering Design is a graduate level course offered by The George W. Woodruff School of Mechanical Engineering at the Georgia Institute of Technology. The course is orchestrated to achieve three objectives, namely, to have students internalize the Pahl and Beitz design method, to help them “reinvent” the Pahl and Beitz design method to meet the challenges of the future, and most importantly, to learn how to continue learning about design. The course was given during the Fall 2000 semester to a class of nineteen students — most in their first semester of graduate school — in addition to six practicing engineers via a distance-learning program. In this paper, the techniques utilized to foster learning in ME6101 are described. Excerpts from students’ essays are presented as anecdotal evidence that the concerted use of these methods aids students both in the internalization of course content and the development of personal practices that will serve them well in and beyond their engineering careers.
The Influence of Product Modularity During Concept Selection of Consumer Products
Authors: Mattson Christopher A. , Magleby Spencer P. 
Published: November 2020

Abstract
The design of modular products, or modular-product design, is a powerful design strategy that can boost the competitive edge of a company that employs its benefits. We introduce in this paper an approach for managing the influence of product modularity during concept selection of consumer products. We propose a process that consists of four steps. The first step is to define the business strategy and associated objectives for the product, based on an expanded definition of modularity. The second step is to prioritize the objectives using an objective tree. The third step is to establish design metrics and the final step is to weigh each metric by the design objectives. The outcome of the process is an overall objective metric (composite score) that is used for concept selection and is a measure of the balance of design objectives affected by modularity. Finally, three product concepts of varying modularity are analyzed using various design objectives to show that the selection of the best (most suitable) concepts depend fully on the design objectives and that the most modular designs are not necessarily the best.
Towards Biomimetic Concept Generation
Authors: Vakili V. , Shu L. H. 
Published: November 2020

Abstract
This paper describes efforts towards generalizing biomimetic concept generation in engineering design. Biomimetic design fully or partially imitates or evokes some biological phenomenon. Nature has often inspired solutions to engineering problems. While biological phenomena hold a vast amount of ideas, a method for finding and using these ideas would make biomimetic innovation faster, easier and more accessible. The paper begins with a brief review of related research, recognition of engineering ideas in biological phenomena and advantages of the natural brand. Next presented are strategies for finding potential analogies in biological phenomena, including searching functionally across multiple levels of organization, from the molecule to the biosphere. Initial efforts at finding appropriate analogies are documented using an example in design for remanufacture.
A Real-Time Multibody Vehicle Dynamics Model Using a Subsystem Synthesis Method
Authors: Kim Sung-Soo , Oh Young-Seok 
Published: November 2020

Abstract
A real-time multibody vehicle dynamics model has been developed using a subsystem synthesis method in a PC-based workstation. The subsystem synthesis method produces 6 × 6 matrix form of equations of motion for the chassis and small size each of suspension subsystem equations of motion separately. Simulations such as, bump-run, stop-and-go, and brake-in-turn have been carried out. Solutions have been validated to compare with those from the model with the conventional recursive formulation. CPU times taken for simulations have been also measured to verify the real-time simulation capability of the proposed vehicle model.
A Precise and Stiffly Stable Time Integration Method for Vibration Equations
Authors: Fujikawa Takeshi , Imanishi Etsujiro 
Published: November 2020

Abstract
A method of time integration algorithm is presented for solving stiff vibration and motion problems. It is absolutely stable, numerically dissipative, and much accurate than other dissipative time integration methods. It achieves high-frequency dissipation, while minimizing unwanted low-frequency dissipation. In this method change of acceleration during time step is expressed as quadratic function including some parameters, whose appropriate values are determined through numerical investigation. Two calculation examples are demonstrated to show the usefulness of this method.
A Control Method for Non-Linear Time-Varying System Using Mixed H2/H∞ Control: Position and Force Control of 2-Link Manipulator
Authors: Kajiwara Itsuro , Yambe Katsuhiro , Nishidome Chiaki 
Published: November 2020

Abstract
Dynamics of multi-link manipulators are highly nonlinear and depend on the time varying configuration. This paper presents a method of gain scheduling which consists in designing a linear time invariant (LTI) controller for each operating point and in switching controller when the operating conditions change. Each LTI controller is designed based on LMI approach in which an optimization problem is defined as a mixed H2/H∞ control problem with pole placement. The performance of the force and the position controls is defined by the H2 norm, and the robust stability according to gain scheduling is evaluated with the H∞ norm and the pole placement of the closed-loop system. The effectiveness and the practicability of the proposed method are verified by both simulations and experiments with 2-link manipulator system.
Influence of Reference Conditions in the Analysis of the Impact of Flexible Bodies
Authors: Escalona José L. , Mayo Juana , Domínguez Jaime 
Published: November 2020

Abstract
In this paper, the floating frame of reference approach is applied to the dynamics of the impact of flexible bodies, while component mode synthesis is used to describe deformation. The influence of the reference conditions, that indicate the type of attachment between the body fixed frame of reference and the flexible bodies, is investigated. Rigid and free attachments allow the use of fixed interface and free interface normal modes, respectively. A finite number of fixed interface modes does not fulfil the natural boundary condition at the attachment point. Free interface normal modes cannot describe the compressive forces at the contact surface. However, it is shown that both set of modes are able to describe the impact-induced elastic waves. In the evaluation of the kinematic coefficient of restitution, these two approaches differ significantly. When free attachment is considered, the derivatives of the reference co-ordinates coincide with the equivalent rigid body velocities of the flexible bodies, remaining constant after the impact. However, if the body frame of reference is rigidly attached, the equivalent rigid body velocities of the flexible body have to be evaluated as a linear combination of the derivative of reference and elastic co-ordinates. The axial impact of a rigid body on a flexible rod and the transverse impact of a flexible pendulum with a fixed stop are simulated to illustrate these facts. Hertzian contact forces are assumed to occur during impact.
Efficient Direct Differentiation Sensitivity Analysis for General Multi-Rigid-Body Dynamic Systems
Authors: Hsu Yuhung , Anderson Kurt S. 
Published: November 2020

Abstract
Sensitivity analysis plays an important role in modern engineering applications where design optimization is desired. A computationally efficient sensitivity analysis scheme is presented in this paper in an effort to facilitate design optimization as it pertains to general, complex multi-rigid-body dynamic systems. Based on the underlying velocity space projection, state space formulation, and direct differentiation approach, the first-order sensitivity information can be efficiently determined in a fully recursive manner for general multi-rigid-body dynamic systems involving an arbitrary number of closed loops. The overall computational expense of this method is bilinear in the number of design variables and the number of system generalized coordinates. The solution accuracy and the computational performance are demonstrated by several numerical examples.
Plastic Deformation of Steel Safety Guardrails
Authors: Neuenhaus Detlef , Kammel Christian , Geßler Urs Joachim , Sedlacek Gerhard 
Published: November 2020

Abstract
In case of contact between two colliding bodies various force interactions in the contact area occur. Therefore, the virtual power for contact zones has to comprise impulse or contact in normal direction and friction in tangential direction of the common plane depending on the way of relative movement. Within this paper a sophisticated algorithm for the description of the virtual power in contact zones is presented. Hence, the implementation of this algorithm to the MEPHISTO (Multibody systems with ElasticPlastic HInges and changeable STructure Organization) multibody program code is successfully proved in the particular case of vehicle impact on a safety barrier system.
The Automatic Stabilization Algorithm for Euler-Lagrange Equations With Holonomic/Nonholonomic Constraints in Multibody System Dynamics
Authors: Pan Zhenkuan , Zhao Weijia 
Published: November 2020

Abstract
A new automatic constraint violation stabilization algorithm for numerical integration of Euler-Lagrange equations of motion of multibody system dynamics based on Baumgarte constraint violation stabilization method and Taylor expansion of constraint functions is presented. The constraint equations may be holonomic or nonholonomic. The parameters α, β, σ used in Baumgarte’s method are determined automatically according to integration step. Some numerical examples compare the accuracy between the traditional method and the one suggested in this paper are presented finally.
Stochastic Analysis of a Fractionally Damped Beam
Authors: Agrawal Om P. 
Published: November 2020

Abstract
This paper presents a general analytical technique for stochastic analysis of a continuous beam whose damping characteristic is described using a fractional derivative model. In this formulation, the normal-mode approach is used to reduce the differential equation of a fractionally damped continuous beam into a set of infinite equations each of which describes the dynamics of a fractionally damped spring-mass-damper system. A Laplace transform technique is used to obtain the fractional Green’s function and a Duhamel integral type expression for the system’s response. The response expression contains two parts, namely zero state and zero input. For a stochastic analysis, the input force is treated as a random process with specified mean and correlation functions. An expectation operator is applied on a set of expressions to obtain the stochastic characteristics of the system. Closed form stochastic response expressions are obtained for White noise. The approach can be extended to all those systems for which the existence of normal modes is guaranteed.
Jorgen Lund: A Perspective on His Contributions to Modern Rotor Bearing Dynamics
Authors: Smalley Anthony J. 
Published: November 2020

Abstract
This paper presents a perspective on the work of Dr. J. W. Lund, in the field of rotor-bearing dynamics. Dr. Lund died on November 16, 2000 — indisputably the father of modern rotor-dynamic analysis. The perspective is somewhat personalized, and supplemented by personal knowledge, coming from someone who has known Dr. Lund for over 30 years, who has benefited from the insights of Dr. Lund, and whose career has been measurably advanced as a result of Dr. Lund’s personal and public contributions.
The paper traces what the author considers to be the most influential work of Dr. Lund, both in published journals, in the software which has shaped the design and problem solution for modern turbomachinery, and in data published in various manuals, government reports, and course notes. It addresses, in particular, his work in oil bearings, gas bearings, unbalance response of flexible rotors, stability of flexible rotors, squeeze-film dampers, rotor balancing, and modal testing of rotors. It provides a road map for those who would revisit the knowledge base, which has shaped the design of high performance turbomachinery for industrial applications. It shows how the work of Dr. Lund has permeated the practice of today’s suppliers of turbomachinery, the users of turbomachinery, and the consultants to the industry. Some of the publications addressed specifically by the paper are the report volumes on rotor-dynamics prepared under contract by MTI, authored by Dr. Lund, and sponsored by the U.S. Air Force in the mid-1960’s, the RPI-MTI short course notes on gas bearings, software documentation, and major papers.
The Scientific Work of Jorgen Lund and a Personal Assessment of its Significance
Authors: Rieger Neville F. 
Published: November 2020

Abstract
A selection of the more important works of Jorgen Lund, are described. The industrial features of the periods in which specific developments in rotordynamics took place are discussed, together with these developments themselves and the investigators who made them. Lund’s contributions are included within the latter part of this framework.
The comparative value of Lund’s work is considered in terms of several criteria, which are judged to apply to the work of investigators generally. These criteria are used to examine the characteristics of three important pioneers of vibration technology, to demonstrate the validity of these criteria. Lund’s contributions are shown to be of high caliber when judged by the same criteria.
Application of Lund’s Stability Analysis Program in Design of Modern Turbomachinery
Authors: De Choudhury Pranabesh 
Published: November 2020

Abstract
The analytical tool developed by Lund has aided in the design and manufacture of modern turbomachinery operating at relatively high speeds, under severe operating conditions, with high gas pressure, and gas density. The purpose of this paper is to show, by means of selected problems, as a practicing engineer in the design of high speed turbomachinery, how the methods developed by Lund aided in the design and problem diagnostics of such turbomachinery.
Theoretical Study on Instability Boundary of Rotor-Hydrodynamic Bearing Systems: Part II — Rotor With External Flexible Damped Support
Authors: Guo Zenglin , Kirk R. Gordon 
Published: November 2020

Abstract
The situation of a rotor-hydrodynamic bearing system in external flexible damped support is more complicated than that discussed before in Part I but it can become an alternative means to improve the stability of the rotor system. A model for both vertical and horizontal analysis is built first. Then, the analytical study on the vertical rotor is conducted. The results show that there might be up to four threshold speeds in this configuration that form a consecutive regional pattern taken turns by stable or unstable regions. Furthermore, the numerical calculation by MATLAB is carried out to obtain the results of the horizontal system. The stability maps for various parametric configurations are presented. It has been shown that the value of support damping has a strong effect on the first several lower threshold speeds. But it has little effect on the last top threshold speed which is mainly determined by the portion of journal mass. Within a certain range of external damping value, the first several regions of instability can be reduced or eradicated. As far as the entire stability map is concerned, there is an optimum range of value for support damping that can make the rotor have only one top threshold speed over the entire running speed range. When the support stiffness is increased, the system stability map becomes narrow which means a small support stiffness is good for broadening the range of optimum external damping.
A New Finding on the Dynamic Stiffness Matrices of Asymmetric and Axisymmetric Shafts
Authors: Raffa Francesco A. , Vatta Furio 
Published: November 2020

Abstract
In this paper the dynamic stiffness method is developed to analyze a rotating asymmetric shaft, i.e. a shaft whose transverse section is characterized by dissimilar principal moments of inertia.
The shaft is modeled according to the Rayleigh beam theory including the effects of both translational and rotational inertia, and gyroscopic moments.
The mathematical description is carried out in a reference system rotating at the shaft speed and is based on the exact solution of the governing differential equations of motion. The exact expressions of the shaft displacements are utilized for deriving the 8 × 8 complex dynamic stiffness matrix of the shaft.
A new relationship is obtained which links the dynamic stiffness matrix of the asymmetric shaft to the 4 × 4 real dynamic stiffness matrix of the axisymmetric shaft.
Modal Control of Flywheel Motion in Magnetic Bearings
Authors: Gosiewski Zdzislaw , Sawicki Jerzy T. 
Published: November 2020

Abstract
Satellite flywheels utilize the solar energy when the satellite is on the Sun side of Earth. When the satellite is in the Earth shadow, the flywheel supplies the inboard instruments with electric energy. This regime of operation causes that angular velocity of the flywheel changes over the wide range. The magnetic bearings are suitable to suspend the flywheel in the vacuum environment. In addition, they can realize other tasks, like for example automatic balancing, diagnostics, or sensor run-out compensation. The control system of magnetic bearings should account for variable plant dynamics, with parameters dependent on angular velocity. The modal approach to control flywheel motion is presented. The control scheme is developed separately for translatory and for rotary motion. The generated results demonstrate that the developed approach is correct and straightforward.
Influence of a Synchronized Self-Shifting Clutch in a Single-Shaft Plant on the Torsional Behaviour of the Shaft Train in Case of Electrical Faults
Authors: Klocke Meinolf , Verstege Stefan 
Published: November 2020

Abstract
Synchro-self-shifting clutches allow the construction of combined gas- and steam power plants as single-shaft systems, which are economically advantageous due to enhanced efficiency and the use of only one generator for gas- and steam turbines.
However, problems occur concerning the question, how to calculate torsional stresses and take into account the operation of the clutch in case of electrical faults.
The article presents calculations of shaft and coupling torques as functions of time carried out by different methods in one exemplary case of faulty operation for a 351MW/228MW combined gas and steam single-shaft plant The clutch is modelled by a nonlinear torsional stiffness.
The calculations show extremely strong impacts of torque inside the clutch due to intermittend engagement and disengagement processes. However, taking additionally into account damping influences inside the clutch one obtains no significant deviations from the results of a calculation for rigid couplings instead of the clutch.
Active Control of Rotor Vibrations by Means of Piezoelectric Actuators
Authors: Carmignani Costantino , Forte Paola , Rustighi Emiliano 
Published: November 2020

Abstract
This work deals with the development of an adaptive hydrodynamic bearing made of a mobile housing mounted on piezoelectric actuators. The device is placed near one of the two bearings supporting a slender shaft. Imposing a harmonic displacement on the mobile bearing, in two orthogonal directions, a rotating force, and hence a correcting moment, can be produced on the shaft so as to reduce the bending caused by the unbalance. The first tests carried out are encouraging and the agreement of experimental and numerical results is satisfactory.
Forced Response of Disks due to Distributed Pressure Fields
Authors: Mohamad A. H. , Ravoux J. , Jacquet-Richardet G. 
Published: November 2020

Abstract
The shape and the frequency of excitation, induced by distributed pressure fields, have both a major influence on the associated response of bladed disks. The way those pressure fields are considered by finite element models have then to be as accurate as possible. In this paper, an analytical model, adapted to the prediction of the forced response of clamped-free circular plates, due to distributed pressure fields, is first derived. This model is considered as a reference in order to assess the effectiveness of different finite element modeling.