bluuebunny/crossref_metadata_2025_split huggingface dataset:
Composite Laminate Stiffnesses and Their Sensitivities
Authors: Geier Bodo , Zimmermann Rolf 
Published: March 2021

Abstract
The great number of possible stacking orders to form laminates suggests to apply optimization, more frequently than usual, in the design of structures made of composite materials. One of the columns upon which optimization of structures is built is the mathematical search procedure for locating a minimum (or maximum) of a constrained function. Efficient algorithms will require the evaluation of derivatives of the object function as well as of the constraints. In that context the sensitivities of laminate stiffness matrices may be required.
In order to meet such a requirement the derivatives with respect to both ply thicknesses and ply angles, of laminate stiffnesses, including transverse shear stiffness, will be presented in this report.
Structural Sensitivity Analysis in Eigenvalue Problems Using Finite Strip Method
Authors: Garstecki Andrzej , Kakol Witold 
Published: March 2021

Abstract
Structural Sensitivity Analysis is performed using the direct differentiation method for buckling and free vibration problems of prismatic thin-walled structures employing the Finite Strip Method. The sensitivity of eigenvalues (critical stresses and free frequencies) with respect to variation of thickness of plate members and with respect to shape-type variations is considered. The differentiation is carried out employing analytical and semi-analytical methods. Numerical examples illustrate the sensitivity of thin-walled plates stiffened with ribs and thin-walled beams. The examples also serve for discussion of numerical efficiency and accuracy of the presented methods.
Stable Workpiece Fixturing
Authors: Donoghue Joseph P. , Howard W. Stamps , Kumar Vijay 
Published: March 2021

Abstract
In this paper, we present the spatial and planar force-displacement relationships which characterize individual contacts on a fixtured workpiece. The compliance at each contact is modeled and expressions for the changes in contact forces as a function of the rigid body relative motion between the fixture elements and the workpiece are developed for three-dimensional fixtures. Using these relationships, the stable fixturing of planar workpieces is demonstrated for material-removal operations. By example, we first describe how to choose the clamp geometry so the overall movement of the workpiece is minimized and then determine the “best” two-contact clamping arrangement using a quality measure based on the deviation from the nominal part dimensions.
Optimization of Stirling Engine Performance Based on Multipoint Approximation Technique
Authors: Toropov Vassili V. , Carlsen Henrik 
Published: March 2021

Abstract
The ideal Stirling working cycle has the maximum obtainable efficiency defined by Carnot efficiency, and highly efficient Stirling engines can therefore be built, if designed properly. To analyse the power output and the efficiency of a Stirling engine, numerical simulation programs (NSP) have been developed, which solve the thermodynamic equations.
In order to find optimum values of design variables, numerical optimization techniques can be used (Bartczak and Carlsen, 1991). To describe the engine realistically, it is necessary to consider several tens of design variables. As even a single call for NSP requires considerable computing time, it would be too time consuming to use conventional optimization techniques, which require a very large number of calls for NSP. Furthermore, objective and constraint functions of the optimization problem present some level of noise, i.e. can only be estimated with a finite accuracy. To cope with these problems, the multipoint explicit approximation technique is used.
Approximate Kinematic Equations for Multiple-Input Small-Crank Mechanisms: Four-Bar Based Mechanisms
Authors: Farhang Kambiz , Basu Partha S. 
Published: March 2021

Abstract
Approximate kinematic equations are developed for multiple-input small-crank mechanisms derived from a basic planar four-bar linkage. Application of a method in which an output link is presumed to comprise a mean and a perturbational motions, the vector loop approach, and a recursive formulation facilitates derivation of the approximate kinematic equations. For a general n-input mechanism, two sets of constraint equations are established: a set of nonlinear recursive equations relating the mean link orientations and a set of linear recursive equations for the purturbational motions. The recursive procedure is demonstrated by developing approximate kinematic equations for four-bar based two-, three- and four-input small-crank mechanisms.
Instantaneous Invariants and Curvature Analysis for Planar Mechanisms
Authors: Yang An Tzu , Pennock Gordon R. , Hsia Lih-Min 
Published: March 2021

Abstract
This paper establishes a systematic procedure to determine the instantaneous invariants for a member in a planar mechanism and the curvature ratios of the path of a point fixed in the member. Closed-form expressions are derived for the instantaneous invariants and the curvature ratios as continuous functions of the input variable of the mechanism. The methods that are proposed in this paper can be applied to the design of planar mechanisms in general. For a given mechanism, the configuration defined by the input variable at which the member achieves the optimal approximation of a prescribed rigid motion can be determined. Alternatively, a point fixed in a member can be selected such that it will generate a trajectory matching a given curve with high precision. For purposes of illustration, the paper details the analytical procedure for a simple epicyclic gear train and a four-bar mechanism. The instantaneous invariants and the curvature ratios are generated for the complete operating cycle of each mechanism.
Polynomial Solution of the Spatial Burmester Problem
Authors: Innocenti Carlo 
Published: March 2021

Abstract
The paper presents a new method for the dimensional synthesis of the spatial guidance linkage that features the guided body connected to the base by the interposition of five rods having spherical joints at both extremities. The linkage is required to index the guided body through seven arbitrarily-chosen rigid-body positions. Core of the proposed method is an original algebraic elimination procedure that allows five unknowns to be dropped from a set of six second-order algebraic equations in six unknowns. As a result, a final univariate polynomial equation of twentieth order is obtained whose twenty roots, in the complex domain, represent as many possible placements for a connecting rod. A numerical example is reported.
Graphical Synthesis of Optimal High-Performance Four-Bar Mechanisms
Authors: Khanuja Sukhwant S. , Mettlach Gregory A. , Midha Ashok 
Published: March 2021

Abstract
Graphical mobility analysis methods are used to develop a comprehensive four-bar mechanism synthesis technique. Given the mobility angle and length of a side link, simple graphical tools are used to obtain the solution space satisfying a variety of constraints on link lengths. This can be done with great accuracy using standard CAD packages. The solution space is then searched for an optimal high-performance mechanism. The objective function seeks to minimize the higher harmonic content in the acceleration of the output member. The graphically generated solution space greatly reduces the search domain of the optimization process. It also readily provides initial estimates for the optimization scheme. Several examples are used to illustrate the methodology.
A More Effective Formulation of the Path Generation Mechanism Synthesis Problem
Authors: Ullah Irfan , Kota Sridhar 
Published: March 2021

Abstract
Use of mathematical optimization methods for synthesis of path-generating mechanisms has had only limited success due to the very complex nature of the commonly used Structural Error objective function. The complexity arises, in part, because the objective function represents not only the error in the shape of the coupler curve, but also the error in location, orientation and size of the curve. Furthermore, the common introduction of timing (or crank angle), done generally to facilitate selection of corresponding points on the curve for calculating structural error, has little practical value and unnecessarily limits possible solutions. This paper proposes a new objective function, based on Fourier Descriptors, which allows search for coupler curve of the desired shape without reference to location, orientation, or size. The proposed objective function compares overall shape properties of curves rather than making point-by-point comparison and therefore does not requires prescription of timing. Experimental evidence is provided to show that it is much easier to search the space of the proposed objective function compared to the structural error function.
Metric Relations and Displacement Groups in Mechanism and Robot Kinematics
Authors: Fanghella Pietro , Galletti Carlo 
Published: March 2021

Abstract
This paper presents a systematic theory for metric relations between the invariant properties of displacement groups, and shows this theory application to mechanism kinematics. Displacement groups, their invariant properties and operations are briefly described. Kinematic constraints are then introduced as tools for relating abstract group properties to actual mechanism constraints. Criteria and operating rules to employ metric relations for the generation of a meaningful set of closure equations for kinematic chains are detailed.
Determination of Branch Free and Circuit Free Solutions During Synthesis of Multiloop Mechanisms
Authors: Mariappan Jawaharlal , Krishnamurty Sundar 
Published: March 2021

Abstract
This paper presents the development of a generic method for the identification of branches and circuits in multiloop mechanisms. This paper also addresses the interrelationship that exists between branches and circuits, and offers a methodical solution procedure for determining branch free and circuit free solutions during synthesis. In this work, the sub-Jacobian method that was earlier developed for finding branching occurrences is further extended to enable identification of circuits and their mobility ranges corresponding to each branching configuration. Using this approach, the circuit analysis is performed by first finding the individual mobility regions of the various loops in the mechanism and then by forming their intersections. The application of this method is illustrated with the aid of six and eight-bar mechanisms.
Unsymmetric Four-Bar Straight-Line Mechanisms With Completely Balanced Deviation
Authors: Gassmann Volker , Funk Wolfram 
Published: March 2021

Abstract
This paper describes a generalisation of straight-line mechanisms of Tchebycheff-type. Tchebycheff considered symmetric four-bar mechanisms for which the part of the coupler curve used as an approximation for a straight line oscillates between two lines, so that one line is a tangent of the coupler curve in three points and the other is a tangent of the coupler curve in two points and intersects the coupler curve in two further points. The described synthesis methods allow the calculation of unsymmetric mechanisms which have the same characteristic oscillation and are also optimal in the sense of the approximation theory developed by Tchebycheff. The use of continuation methods not only enabled the solution of a classical kinematic problem and the possibility to synthesize straight-line mechanisms with desired characteristic values but also offers new possibilities for user-friendly software for kinematic synthesis.
A Method for Generating Geared Links From Linkages
Authors: Wang Wan , Li Guen Xie , Tao Yong Zhong 
Published: March 2021

Abstract
A concept of generating geared links by inverting general linkages is proposed, which is based on the topological graph, and applies substitution principle of mechanisms. It makes it possible to apply the methods, data and computer programs of general linkages to geared links.
Application of Learning Control Theory to Mechanisms: Part 2 — Reduction of Residual Vibrations in High-Speed Electromechanical Bonding Machines
Authors: Chew M. , Phan M. 
Published: March 2021

Abstract
Learning control provides an integrated approach for handling inverse kinematics and inverse dynamics of mechanisms, in the presence of parametric errors in system modeling. This technique is applied to reduce residual vibrations at the bonding cap of an electromechanical bonding machine for integrated circuits (ICs); a process of electrically linking silicon chips to the leads. The bonding cap trajectory for the bonding motion is actuated by high-speed cams driven by electric motors. The primary causes of residual vibrations are due to errors in the design model of the nonlinear electromechanical system, in camshaft speed control, as well as, in cam profile fabrication. This article demonstrates the capability of learning control to reduce the residual vibrations in such machines, by compensating for these sources of errors.
A Note on the Experimentally-Determined Elastodynamic Response of a Slider-Crank Mechanism Featuring a Macroscopically-Smart Connecting-Rod With Ceramic Piezoelectric Actuators and Strain Gage Sensors
Authors: Thompson B. S. , Tao X. 
Published: March 2021

Abstract
An experimental investigation is presented into the elastodynamic flexural response of a smart flexible connecting-rod of a planar slider-crank mechanism which features both macroscopic actuators and sensors. This connecting-rod was synthesized with two thin PZT ceramic piezoelectric plate actuators bonded to the flanks of the beam-like member at the mid-span of the link, which were employed to reduce the magnitude of the flexural response when they were activated by amplified signals emulating from two strain gage sensors bonded to the surfaces of the piezoceramic actuators. The authors believe that this is the first paper to present experimental results for a linkage featuring this class of smart materials, and these results will hopefully motivate more theoretical studies on mechanism systems fabricated from this class of biomimetic materials. The results from this preliminary investigation add credibility to the proposition that this new generation of macroscopically smart materials will have a significant role to play in the design of the next generation of machines and mechanisms.
Computational Techniques for Finite Element Method Based Kineto-Elastodynamic Analysis of Mechanisms
Authors: Mahna Vinod K. , Asnani Nanik T. 
Published: March 2021

Abstract
The aim of computational techniques employed for the kineto-elastodynamic analysis of mechanisms is to evaluate the strain induced at any prescribed location in an elastic constituent link of the mechanism. The problem to be grappled is one of multi-degree-of-freedom coupled differential equation and is amenable to its solution by the modal analysis and numerical integration techniques. This formidable problem calls for imposition of boundary conditions and inter-link compatibility requirements, assembly of elemental matrices, incorporation of geometric stiffness matrix, evaluation of non-symmetric coupling term matrices, elimination of rigid-body degrees of freedom, transformation of local constraints pressed upon by the kinematic joints to the global frame before the stage gets propitious to embark upon the solution procedure. This paper enlarges upon the computational aspects involved in the kineto-elastodynamic analysis of mechanisms using finite-element method.
Stress Analysis and Optimal Cross-Section Design of Noncircular Spring Wire
Authors: Le Li , Lin Yuyi 
Published: March 2021

Abstract
The stress distribution of noncircular cross sections of straight rods and helical springs is studied. The Poisson equation describing the torsional stress on an irregular region is solved by using a special finite difference operator. The stress distribution of several cross sections of both straight rods and helical springs are obtained numerically and then verified by comparison to available analytical solutions. Using this numerical approach, the optimal ovateness values as a function of the spring indices is found. Moreover, a new cross section, which is a modified polynomial of degree four, having more uniform stress distribution is discovered.
Optimal Design of Elastic Linkage Mechanisms With Multi-Frequency Constraints
Authors: Xianmin Zhang , Yunwen Shen , Hongzhao Liu , Weiqing Cao 
Published: March 2021

Abstract
The paper presents a finite element method for minimum weight design of flexible mechanisms with multiple frequency constraints and upper and lower bound constraints on the design variables. The design algorithm developed in this paper is formulated in terms of the Kuhn-Tucker optimality criterion, in which two damping factors are introduced to guarantee the algorithm possesses good stability and convergence. The first and second order design sensitivity analysies of eigenvalues are presented and the values of the damping factors α and β are recommended. Results of three numerical examples show that the algorithm is stable and the optimal design can be obtained in lsee than fifteen iterations.
A General Approach to the Determinations of Planar and Spatial Cam Profiles
Authors: Tsay Der Min , Wei Hsien Min 
Published: March 2021

Abstract
A systematic development for the theory of envelopes with proof is presented. It offers a simple and general procedure to determine the planar and spatial cam profiles. Based on the theory, a planar or spatial cam profile is defined as the envelope of its follower surfaces represented in parametric form in different relative positions of the cam and the follower. The procedure is illustrated by determining the two-dimensional and three-dimensional cam profiles with analytical expressions. To show its accuracy and effectiveness, the results are then compared to those obtained by an earlier approach using the screw theory.
A Finite Element Formulation of Flexible Slider Crank Mechanism Using Local Coordinates
Authors: Fallahi Behrooz , Lai S. , Venkat C. 
Published: March 2021

Abstract
The need for higher productivity has lead to the design of machines operating at higher speeds. At high speed the rigid body assumption is no longer valid and the links should be considered flexible. In this work a method which is based on Modified Lagrange Equation for modeling flexible mechanism is presented. The method posses a more computational efficiency for not requiring the transformation from the local coordinate system to the global coordinate system. Also an approach using the homogeneous coordinate for element matrices generation is presented. The approach leads to a formalism where the displacement vector is expressed as a product of two matrices and a vector. The first matrix is a function of rigid body motion. The second matrix is a function of rigid body configuration. The vector is a function of elastic displacement. This formal separation helps to facilitate the generation of element matrices using symbolic manipulations.
Motion of a Sphere on a Plane
Authors: Xu Yong-Xian , Kohli Dilip , Vezina Larry , Speranza Daniel R. 
Published: March 2021

Abstract
The motion of a sphere on a plane is a five degree-of-freedom motion. It consists of two independent translations of the geometric center of the sphere and three rotations corresponding to gyroscopic motion of the sphere. The trajectory of an imbalanced sphere on the plane depends on: (1) the physical and inertia properties of the sphere, (2) the initial conditions of motion, and (3) the friction between the sphere and the plane. To predict the trajectory of the sphere, a general Eulerian mathematical model is developed which takes into account these conditions. The mathematical model is verified through experimentation. For the first time, general characteristics of the translatory and rotatory motions of the imbalanced sphere with general inertia distribution are presented. The existence of the “break point” in the trajectory is illustrated by examples. The trajectory (track) of the contact point on the surface of the sphere is also analyzed.
Developing a Pedagogically Effective Programming Environment for Teaching Mechanism Design
Authors: Cheng Harry H. 
Published: March 2021

Abstract
The CH programming environment is an open system. Users can enhance the system through its various user interfaces. CH is specially designed for applications in mechanical systems engineering, although it is applicable to many other disciplines as well. Due to our interest in teaching, we intend to develop it as a pedagogically effective programming environment for teaching and student learning. CH has been successfully used as a teaching and learning tool for an undergraduate course, Computer-Aided Mechanism Design, at University of California, Davis in Fall 1993. In this paper we will present the CH programming environment and programming features developed for teaching and student learning. We will describe how a teaching tool-box is developed and used for teaching mechanism design. Source codes in the teaching tool-box are available to students so that they can study the software implementation of algorithms and modify the codes to solve the similar problems. Although the developed teaching tool-box is specific for instruction on mechanism design, the CH programming environment and ideas presented in this paper are general, and they are applicable to instructional improvement for a wide range of subjects in engineering.
Variable Stroke Piston Mechanism for Spark Ignition Engines
Authors: Elkholy A. H. 
Published: March 2021

Abstract
The concept of load control in internal combustion engines by eliminating the inlet throttle and replacing it by controlling the piston stroke has gained great publicity recently. Nevertheless, certain design parameters should be considered in order to make this concept worthwhile. In this study, an optimized mechanism for varying engine stroke has been introduced. A criteria based upon the use of complex numbers technique was used to analyze the mechanism kinematically and dynamically and the results were then verified using graphical solution. The mechanism was found to produce up to 56% stroke variation within the control actuator capabilities. The compression ratio was found unchanged (within ± 6%) which helps maintain steady combustion process. The entire mechanism is well tuned and no spark plug timing adjustment is required during stroke variation. The piston side thrust due to connecting rod angularities was found fairly low and should not impose any wear problems in the engine cylinder walls.
Effects of Design-Kinematic Parameters on Loading Capacity of Disc Cams With Translating Followers
Authors: Su Daizhong 
Published: March 2021

Abstract
The aim of this research is to investigate the effects of design parameters on disc cams’ loading capacity. A kinematic-Hertzian stress parameter (KHS) and a kinematic-elastohydrodynamic lubrication parameter (KEHL) are derived first, which reflect the combined contributions of kinematic parameters to Hertzian stress and elastohydrodynamic lubrication film thickness respectively, and then KHS and KEHL are analyzed against each design parameter. Based on the analysis, guidelines for cam mechanism design are proposed.