bluuebunny/crossref_metadata_2025_split huggingface dataset:
Towards a New Science of Functional Design
Authors: French Michael 
Published: April 2021

Abstract
This paper maintains that there should be a science of functional design, based upon all the design ideas developed by engineers and others over the centuries, ordered, generalised and combined into a coherent system. It sketches some ways in which such an ordered system of design knowledge might be built up, the study of design principles (such as kinematic design), systematic invention by the study of known means, and the study of limits.
Cumulative Results of Concept Generation by Individuals in a Mechanical Design Class
Authors: Kicher Thomas P. , Robie Bruce H. 
Published: April 2021

Abstract
A study of the concept generation abilities of individuals in a senior level mechanical engineering design class was performed. The study also examined the number of subjects identifying each concept. Results from two tests were standardized based on the number of distinct concepts identified by the sample. Sixty-five students participated. Tests were scored based on the number of concepts generated. Concepts were defined based on a categorization scheme (Pahl and Beitz, 1988).
Counting the number of concepts generated and standardizing based on the sample provide measures for the study of concept generation methodologies. Between sixty and seventy percent of all concepts were identified by less than ten percent of the sample. Concepts generated by fewer than ten percent of the sample were termed uncommon and were generated by most of the sample. Design groups may generate more concepts if the each individual’s uncommon concepts are accepted by the group.
Design Optimization for Robustness Using Performance Simulation Programs
Authors: Sundaresan Sivakumar , Ishii Kosuke , Houser Donald R. 
Published: April 2021

Abstract
This paper presents a methodology to incorporate manufacturing and operational variances in the design optimization stage to achieve robust and optimal performance. The procedure uses Taguchi’s orthogonal arrays to approximate the expected value of performance during optimization. This approach reduces the number of function evaluations in problems that use computationally expensive performance simulation programs. Hence, the method allows incorporation of variances on many variables simultaneously. This paper uses two illustrative examples: 1) Design of helical gears that have minimum transmission error and at the same time are less sensitive to manufacturing errors, 2) Design of beverage cans where we minimize the effects of errors in tooling on can weight and structural requirements. The optimal robust design shows a considerable decrease in sensitivity to manufacturing and operational variances and, at the same time, has good performance.
Automatic Generation of Well Structured Meshes Using Medial Axis and Surface Subdivision
Authors: Armstrong C. G. , Tam T. K. H. , Robinson D. J. , McKeag R. M. , Price M. A. 
Published: April 2021

Abstract
This paper reports on a project in which automatic mesh generation is divided into two phases. In the first phase feature recognition and shape grammar techniques, based on the medial axis of a 2D region, are employed to decompose a complex component into a number of simple subregions. In the second phase the subregions are meshed to a controlled density using conventional mapped mesh methods. The advantage of this approach is that good quality meshes of quadrilateral elements can be generated in 2D and, potentially, meshes of hexahedral elements in 3D. A parallel program of work has concentrated on the analysis of errors: different methods for error estimation and for providing transitions in mesh density have been compared.
Tolerances and Available Relative Motions in Bolted Connections
Authors: Delvecchio Joseph N. , Soom Andres 
Published: April 2021

Abstract
The implications of geometric and dimensional tolerances on the mechanical behavior of assemblies are often indirect or unclear. Although current tolerancing practice will generally assure that components will assemble, one may also be concerned with other aspects of the functionality of an assembly. In this paper we examine one aspect of functionality, namely the effect of statistical tolerances of location on the amount of available motion or play that can occur in bolted assemblies. A mobility formulation is proposed which allows the possible part motions to be determined in terms of one of two indices, i) the average Available Translation or Rotational Motion and ii) the Relative Mobility Area. A Monte Carlo simulation is used to perform the mobility calculations. The hole locations and tolerances are normalized, allowing the available motion of assemblies with different numbers of holes and configurations to be compared. It is shown that the geometric arrangement of holes does not significantly affect mobility. Increases in average hole to hole distance reduces available rotational motions but not translations. A decrease in available motion is shown to occur as the number of hole features increases. This decrease in quantified by means of the above indices.
Algorithms for Nesting of Ship/Offshore Structural Plates
Authors: Cheok B. T. , Nee A. Y. C. 
Published: April 2021

Abstract
This paper discusses the development of a set of algorithms for the automatic nesting of ship/offshore structural plates. The algorithms are developed to take advantage of the peculiarity of most ship/offshore structural plates with the aims of optimising material usage and minimising computer search time. The parts to be nested are first processed by a shape processing routine which employs a simple feature extraction approach to classify the plates according to predefined rules specially adopted for ship/offshore structural shapes. The most appropriate search path for each class of plates is used to obtain the best enclosing rectangle for similar shapes. The search paths are based on heuristics developed to simulate the manual method used by the human operator. Finally, all the plates are laid out on the stock sheet using a “rectangle packing” approach. A computer package, Patnest-Ship was developed to demonstrate the efficiency of the algorithms and very encouraging results are achieved. The input and output files to and from Patnest-Ship are described in DXF format so that it can be integrated with existing CAD/CAM systems. Pre- and post-processors for this package have been implemented on AutoCAD to permit the user to define the plates and interactively improve on the solutions provided by Patnest-Ship, if necessary.
Development of Kinematic/Kinetic Performance Tools in Synthesis of Multi-D.O.F. Mechanisms
Authors: Lee Ming-Yih , Erdman Arthur G. , Gutman Yevsey 
Published: April 2021

Abstract
Kinematic and kinetic performance are important issues in designing multi-degree of freedom mechanisms such as robotic manipulators. In the engineering design stage, it is especially important that the designer can grasp the characteristics of the mechanism. The aim of this study is to develop a means of representing the kinematic and kinetic performance of the mechanism in such a way that the performance characteristics are quantified analytically and visible graphically to the designer in their entirety in the conceptual design stage. Various performance indices derived from the Jacobian matrix and its quadratic form. These performance indices are the local kinematic cross-coupling index, the local directional mobility index, and the local efficiency index. Graphical images of these performance characteristics using eigen-ellipsoid and workspace trajectory contours are introduced. Critical performance points in mechanism workspace are identified and elaborated for design considerations. Based on the graphical representation of these performance characteristics, design rules for achieving different performance objectives can easily be implemented. This method is applicable to computer-aided design of a mechanism and predetermination of its kinematic and kinetic performance.
Human Aspects of Design Work
Authors: Norell Margareta , Hovmark Svante 
Published: April 2021

Abstract
Conclusions and experiences from three examinations within a Swedish interdisciplinary research project (MANDECO) are discussed in this paper. The purpose of the research work is to find ways to satisfy both demands on the effectiveness of the designer in the product development process and personal demands from the designers on the working situation. Interviews, questionnaires and experimental studies in industrial companies and in the technical university are used to find variables related to an estimated product development process. CAD-work, implementation of the Design for Manufacture concept and Simultaneous Engineering in co-operation between design and manufacturing are important issues in the paper. Some conclusions from the use of computer tools in design work from studies in the project are: The systems should be developed to support calculations, analysis, routine work and knowledge transference in the design process and preferably to be used less than an average of about 30 hours/week to restrict physical complaints. Co-operation between design and manufacturing is supported if the same tools can be used in the two departments, if the knowledge in the system is uncontroversial and if the process is organized to support person-to-person discussions.
Kinematics of the Ball Screw Mechanism
Authors: Lin M. C. , Ravani B. , Velinsky S. A. 
Published: April 2021

Abstract
This paper studies the kinematics of the Ball Screw Mechanism (BSM) with the aim of developing a foundation for understanding the motion of the balls and their contact patterns with the contacting elements. It is shown that there is always slip between the balls and the nut or screw, and therefore, the no slip condition assumed in the BSM literature is not attainable. The effect of contact deformation on the motion of the balls is also studied and is used to develop the pattern of the constant sliding lines of contacts between the ball and the screw or the nut. The results have applications in efficiency analysis, design, wear analysis and finite element modeling of the BSM.
A Technique for the Design of an Interference Free Complex Planar Mechanism
Authors: Ling Zhi-Kui , Chase Thomas R. 
Published: April 2021

Abstract
A complex planar mechanism is usually represented by its simplified schematic representation, called the kinematic skeleton, in both synthesis and analysis. Unfortunately, interferences between links may not be evident from the kinematic skeleton. This paper presents a computer aided top-down technique to design the geometry of an interference free mechanism. The method is intended to replace intuitive and trial and error link geometry design techniques.
The geometric design of the links of a mechanism is initiated after the kinematic skeleton diagram is created using existing synthesis and analysis techniques. The solution to the interference problem is initialized by placing links into different layers. To ensure a link, called a reference link, does not interfere with other links within its layer, the work space of those links with respect to the reference link is generated. The resulting domain, called a “swept area”, establishes an illegal region whose complement identifies the feasible region to place the geometry of the reference link. The new method is demonstrated with an example.
A Strategy for Characterizing the Stability of Parts Fixtured Under Three-Point Frictional Constraint
Authors: Linder K. J. , Cipra R. J. 
Published: April 2021

Abstract
Flexible assembly systems require flexible fixtures which can constrain parts in a stable fashion and will adapt quickly and easily to a change in the type of part. A fixtured part is either unstable or stable depending on whether or not it moves when the clamping force is applied. This paper gives a systematic method which uses graphical techniques to characterize the stability of parts fixtured under a particular type of three-point frictional constraint. The three inputs into this method are the location of the center of gravity of the part and the geometrical and frictional properties of the fixturing system. No information about the applied clamping force is necessary for the method to characterize stability. The method first determines if it is possible that static equilibrium will not occur when the clamping force is applied. If this possibility exists, then corresponding kinematically possible motions are determined and are tested for consistency with dynamics to determine if any of them are a possible unstable mode. Finally, the method classifies a part into one of three classifications: stable, unstable, or indeterminate. If it is determined that there are no possible unstable modes then the part is stable. But if it is determined that static equilibrium cannot occur then it is unstable. If it is discovered that static equilibrium is possible yet possible unstable motions also exist then the stability of the part is indeterminate. In spite of these stability indeterminacies, the method can determine all possible unstable motions of both unstable and indeterminate parts. This characterization of the stability of parts can provide useful feedback as to how a fixture configuration can be modified in order to either provide or improve a stable clamping arrangement.
The Effects of Harmonic Drive Gears on Robot Dynamics
Authors: Lin Tsung-Chieh , Yae K. Harold 
Published: April 2021

Abstract
Mathematical models of the harmonic drive have been developed, and their effects on manipulator dynamics have been examined. The harmonic drive is modelled as a flexible gear with a high gear reduction ratio. The recursive Newton-Euler dynamic formulation is applied to deriving the system equations of motion that include the effects of the geared actuation. The equations include not only the nonlinear dynamic coupling between rotors and links but the gyroscopic effect due to the spinning rotors. Different modelling assumptions creates four models and their time responses are compared. As an example, a seven degree of freedom robot was chosen to make comparisons in time responses.
Automatic Planning of Smooth Trajectories for Pick-and-Place Operations
Authors: Gosselin Clément M. , Hadj-Messaoud Ammar 
Published: April 2021

Abstract
This paper proposes some new polynomial solutions to the trajectory planning problem encountered in pick-and-place operations. When a robotic manipulator is used for such operations, it is possible to plan the required trajectory in joint space, provided that the inverse kinematic problem has been solved for the initial and final configurations — and possibly for a lift-off and a set-down configuration — and that the workspace is free of obstacles. Polynomial solutions to this problem can be found in the literature. However, they usually provide continuity up to the second derivative only, leading to a discontinuous jerk. The solutions derived in this paper preserve the continuity of the third derivative of the joint coordinates, thereby ensuring smooth trajectories with smooth variations of the actuator currents. Moreover, whenever possible, unique polynomial expressions valid between the initial and final configurations are used in order to simplify the logic. Polynomial formulations without lift-off and set-down configurations are first presented. Then, these intermediate configurations are introduced, leading to a new set of solutions. A global algorithm is then discussed in order to clearly indicate the relationship between the different solutions. Finally, an example illustrating the application to a pick-and-place operation is solved.
H
∞ Control of Smart Structure Helicopter Rotor Blade
Authors: Kashani R. , Melkote S. , Sorgenfrei A. 
Published: April 2021

Abstract
Active vibration control of helicopter rotor blade is studied. For the purpose of illustration, we have considered only flap wise vibration of a hingeless rotor blade, and modelled it, using finite element method, by 20 beam elements. The first 12 bending modes of the system are considered in the model. A H∞ controller is designed for the plant formulated as above.
The result of the numerical simulation of the closed-loop system shows that the control introduces an appreciable amount of damping in the frequency region of interest. The consideration of the modelling uncertainty in the synthesis of the controller resulted in a design which is robust stable in presence of formulated model uncertainty.
Analytical and Experimental Investigation on Vibration Control of Piezoelectric Structures
Authors: Tzeng M. J. , Wu W. Z. 
Published: April 2021

Abstract
Active vibration control of smart structural materials (beam and plate) has been achieved by using distributed piezoelectric actuators. Numerical simulation and experimental testing have been conducted to investigate vibration suppression of the advanced structures. Results from simulation and testing are in satisfactory agreement.
A Darwinian Approach to the Actuator Number and Placement Problem With Nonnegligible Actuator Mass
Authors: Zimmerman David C. 
Published: April 2021

Abstract
The problem of optimal actuator number and placement for the vibration control of large flexible space structures is addressed in this work. The inherent mass of the actuators is integrated in the number and placement algorithm. The algorithm utilizes concepts from genetic programming, which is loosely based on Darwin’s “survival of the fittest” theories. The paper develops the genetic algorithm in the context of the actuator number and placement problem. Examples are presented which demonstrate the genetic algorithm and the effect of actuator mass on the placement and number problem.
Simulation and Experiment Study on System Identifications of Elastically Jointed Structures
Authors: Rong Y. , Tzou H. S. 
Published: April 2021

Abstract
The dynamic characteristics of elastic joints strongly affect the dynamic performance of a jointed structure. In order to study the performance of elastically jointed structure, a theoretical model of elastic joints has been developed based on the concept of dynamic contacts, in which the joint friction and clearance effects are included. A stochastic simulation technique is used to evaluate the system characteristics of jointed structures. In this paper, a time-domain system identification method is presented, which is applied to estimate the dynamic contact parameters of elastic joints and the eigenvalues of jointed structures. The identification system may use the data generated by using the theoretical model, or from experimental tests. The joint contact stiffness and contact damping are identified to be directional dependence of contact angles. The system natural frequencies and damping ratios are varied upon joint clearance variations. The simulation and experiment results are presented in this paper, and show comparisons.
Vibration Control and Shape Adjustment of Truss Structures Using Piezoelectric Actuator
Authors: Sekine Koji , Shibayama Yozu , Iwasawa Naotoshi , Inada Hiroshi , Yoshida Shiro , Arikabe Takeo , Natori Michihiro 
Published: April 2021

Abstract
In the field of structural dynamics of large space structure (LSS), control/structure interaction technologies have been attracting much attention of researchers, and various types of control theory have beer, proposed. Meanwhile, it is important to develop actuators for the use of structural control. Piezoelectric device has some advantages characteristics such as compact size, high frequency response, low energy consumption over the other devices. With this background a uniquely designed piezoelectric actuator both for active dumping and shape adjustment has been preliminarily developed for experimental use. This paper describes the experimental results of the actuator for active dumping of planar truss and for statical or dynamical shape adjustment. And numerical simulations of planar truss with minimum numbers of pairs of collocated actuators and sensors show that a state observer can estimate truncated modes precisely and that the excited vibration can be dumped out rapidly.
On the Dynamics of Perturbed Symmetric Systems
Authors: Happawana G. S. , Nwokah O. D. I. , Bajaj A. K. 
Published: April 2021

Abstract
In this work, we consider the dynamics of linear mechanical systems possessing geometrical symmetry subject to differential or small parameter variations. The machinery of group theory including the irreducible group representations, and the consideration of representations to which the translational, rotational and vibrational modes belong, allow us to predict apriori, the number and the order of degenerate eigenvalues in the symmetric system. By considering the resultant Hamiltonians of the perturbed symmetric system, we show further the effects of the perturbations on the eigenvalues and their degeneracies. Since the vibration modes of systems with degenerate eigenvalues are known to display sensitive dependence on parameters, we may use these techniques to identify in principle the possibility of maximum vibration amplitudes and where they are likely to occur. Applications of these ideas include the mistimed turbine rotor bladed disk assemblies.
Design of an Almost Critically-Damped Single Robot Arm
Authors: Abdelhamid Mohamed K. , Ko Kuan-Yuh 
Published: April 2021

Abstract
Modern, fast, and light robot arms are more susceptible to vibration problems than the old, slow, and massive robot arms. Passive vibration control using damping and dynamic absorbers may be used to decrease the settling time of the robot arm after it has been driven to its desired position. Implementation of an optimally damped vibration absorber has been recently investigated and results showed success in shortening the settling time of a single robot arm. This paper realizes that a critically damped structure is the fastest structure to settle in its static equilibrium position. This paper, thus, uses recent results on damping ratios of multi-degree-of-freedom systems to provide a design scheme that uses both a damped vibration absorber and distributed damping (such as a damping layer) with the robot arm to realize an almost critically damped design. Simulation results show that the new design method results a single arm link design that is faster to settle than the previously published designs.
Design of Magnetic Bearings for Rotor Systems With Harmonic Excitations
Authors: Dhar D. , Barrett L. E. 
Published: April 2021

Abstract
This paper presents a method for calculating the control forces and the bearing stiffness and damping coefficients to control the response of multi-mass flexible rotor systems mounted on magnetic bearings and subjected to unbalance or harmonic excitation forces. The capability for inclusion of hydrodynamic bearings is retained to model seal effects or to permit the design of magnetic bearings for hybrid systems. Control forces at the magnetic bearing locations are evaluated based on the desired shaft response specified by the modal coordinates. These forces are determined such that the error between the desired response and the achieved response is minimized in a least-square sense. Equivalent bearing coefficients are calculated from the control forces and the achieved response, which when superimposed on the nominal bearing coefficients yield the resultant magnetic bearing coefficients required for control. An example case is presented where control of rotor response has been attempted at the first and the second unbalance critical speeds. The results demonstrate appreciable improvement in response using magnetic bearings.