bluuebunny/crossref_metadata_2025_split huggingface dataset:
Driven Pulley Jumping of Timing Belts
Authors: Gerbert Göran 
Published: March 2021

Abstract
A model and criterium for the jumping limit torque of timing belt drives are presented. The following parameters are considered: pulley geometry, belt geometry, belt strain stiffness, belt tooth stiffness, belt flexural rigidity, shaft stiffness and initial tension. Friction is important in separating jumping on driver and driven pulleys since the jumping behaviour is different at the two sides. Other parameters might influence the jumping limit torque as well. Moreover, great care must be taken to get good parameter data from the test setup.
The present analysis is restricted to driven pulleys. Calculated results of jumping limit torque and shaft load are presented for an XL-belt drive. The results exhibit the same behaviour as test results presented in the literature.
Engagement of Oil Immersed Multi-Disc Clutches
Authors: Jacobson Bengt 
Published: March 2021

Abstract
Oil immersed clutches are often treated without respect to the oil being present, i.e. the torque is assumed to be a pure dry friction torque, directly controlled by the actuating force. However, during the engagement this is sometimes not enough. The oil film acts in two ways: Firstly, the oil has to be squeezed out before dry friction can be developed. Secondly, before the friction surfaces have reached contact, the torque is viscous. This work proposes equations that take these phenomena into account. A simple model for the transition from viscous to dry friction is used. Compensation for grooves in the friction surface is made. Also the hydraulic actuating equipment (piston, return spring, orifice etc.) is modelled. Simulation results are verified by experiments.
A Generation Mechanism of Aerodynamic Sound of Spur Gears
Authors: Houjoh Haruo , Umezawa Kiyohiko 
Published: March 2021

Abstract
It was already discovered that a pair of spur gears generates the tooth mesh frequency sound due to a fluctuating air flow. This sound is generated independently from the sound corresponding to mechanical vibration. In this study, to clarify the detailed generation process of the sound including the Level Trough which is one of specific feature of sound emission, experimental investigations were performed. It has been found that there is two sorts of sound; one is placed at the middle in the mesh end region, and is point source which appears when the air flow velocity reaches a critical speed. The other one is placed at both face end surfaces, whose magnitude decreases by either shortening center distance or shallowing tooth root spaces even though the air flow velocity increases. By assuming that the air flow comes from the pumping through the mesh process, a general explanation for the sound generation is presented.
Bearing Vibration and Oil Film Thickness in Relation to Sphericity of Bearing Steel Balls
Authors: Itoigawa F. , Nakamura T. , Funabashi K. 
Published: March 2021

Abstract
The relationship between the bearing vibration and the sphericity of the steel balls used for ball bearings is experimentally investigated in consideration of the oil film in between the steel balls and raceways. The experiments are carried out on angular contact ball bearings (7208C and 7010C) under only thrust load. First, it is confirmed that the oil film thickness, which is measured on this bearing, virtually agrees with the value calculated by EHL theory. And even if there exists a considerably large error in the ball shape, it does not always necessarily rupture the oil film if it is sufficiently thick. Second, in a simple two-bearing-shaft system, the even-order undulation of form error of ball, especially, second-order undulation, can cause bearing vibration. Furthermore, when the ball has a three-dimensional shape like a rugby ball, with elliptical cross-sections, the ball determines its own rotational axis.
Optimization of Involute Gear Tooth Profile Modification for Tooth Scoring Reduction
Authors: S'roda Prokop , Huston Ronald L. 
Published: March 2021

Abstract
This paper presents a method for determining optimum involute tooth profile modifications to reduce scoring and to increase load bearing capacity. The method is based upon Bloks theory of lubrication and wear. The method leads to design charts incorporating common geometrical gearing parameters. An example is presented.
Aspects in the Shape Optimization Using Brittle and Ductile Materials
Authors: Eschenauer H. A. , Vietor T. 
Published: March 2021

Abstract
The use of advanced materials will increasingly gain importance in future developments of constructions in mechanical, electrical and civil engineering. For this reason, the material behaviour in particular has to be considered when finding optimal layouts for components. Here, the different failure mechanisms of the applied materials must be taken into consideration. This paper presents a comparison between conventional, ductile materials and brittle ceramics as an example of an advanced material. In order to find a failure criterion which is characteristic of the material, stochastic models of the defects determining the failure of ceramic materials have been included. A strong variation in the calculated optimal design shows that an accurate consideration of the material behaviour and its mathematical description is important for the results to be found. The use of conventional stress criteria does not suffice for ceramic materials.
The Explicit Approximation Method for 2-D Shape Optimization Under Displacement Constraint
Authors: Hsu Yen-Liang , Sheppard Sheri D. , Wilde Douglass J. 
Published: March 2021

Abstract
The Explicit Approximation Method for 2D shape optimization under displacement constraint is presented. This is a zeroth order sequential approximation method. The basic idea is to use mechanical knowledge instead of purely numerical gradient information to form an explicit approximation to the implicit constraint. Design examples are presented to show that the displacement constraint usually has a good explicit approximation in 2D problems, and a good and feasible, if not theoretically optimum, design can be found very efficiently by the Explicit Approximation Method using only zeroth order information.
A Knowledge Based System for Intelligent Process Planning
Authors: Yu Jin , Liou F. W. , Tong Zhongfang , Sun Yueming 
Published: March 2021

Abstract
Knowledge extraction and representation are the two most important problems to build up expert systems. This paper describes an example of a knowledge based prototype Hi-KJBIPP, which is designed in a hierarchical architecture to express different levels of machining knowledge for complex box-type workpieces. Production systems and frames are both used as knowledge representation methods in Hi-KBIPP. A production rule system is used to represent top levels of knowledge, in which the control strategies that consist of priority classification, priority execution, and context restriction are designed to decide the first rule to be executed when several rules are of the same qualification. Frames are used to represent the information of machining procedures. A particular frame system is used in Hi-KBIPP which provide multi-dimension frame, similarity network, and associate-network to handle and compile knowledge.
Design of a Non-Homogeneous Annular Disk Under Pressure Loadings
Authors: Gau Chung-Yun , Manoochehri Souran 
Published: March 2021

Abstract
A method for the design of non-homogeneous, variable-thickness, annular disks under internal and external pressures satisfying Tresca yield criterion is presented in this paper. The effects of varying the disk thickness and stiffness properties to achieve a fully stressed design are investigated. Analytical solutions for distributions of Young’s modulus and disk thickness variations have been developed for the case of fully stressed designs. Examples are given for three different cases, namely, constant thickness with variable Young’s modulus, variable thickness with constant Young’s modulus, and variable thickness with variable Young’s modulus. In the last case, due to the existence of many alternative solutions, optimal design techniques have been utilized and the results are presented.
Discrete Optimal Design Formulations: Application to Gear Train Design
Authors: Pomrehn Leonard P. , Papalambros Panos Y. 
Published: March 2021

Abstract
The use of discrete variables in optimal design models offers the opportunity to deal rigorously with an expanded variety of design situations, as opposed to using only continuous variables. However, complexity and solution difficulty increase dramatically and model formulation becomes very important. A particular problem arising from the design of a gear train employing four spur gear pairs is introduced and formulated in several different ways. An interesting aspect of the problem is its exhibition of three different types of discreteness. The problem could serve as a test for a variety of optimization or artificial intellegence techniques. The best known solution is included in this article, while its derivation is given in a sequel article.
Infeasibility and Non-Optimality Tests for Solution Space Reduction in Discrete Optimal Design
Authors: Pomrehn Leonard P. , Papalambros Panos Y. 
Published: March 2021

Abstract
Techniques to be employed for nonlinear design optimization with discrete variables are studied in the context of a particular problem arising from the design of a gear train. The mathematical model formulation was presented in an earlier article. In this sequel, a solution derivation is described, patterned as a multistage process. After certain reformulation and relaxation, a variety of infeasibility and non-optimality tests are performed, greatly reducing the size of the space containing the global optimum. Methods used to investigate the remaining space do not guarantee a global optimum, but could be replaced by more costly methods that do provide such guarantees. A global infimum is generated, bounding any improvements on the best known solution.
Optimum Design of Rotational Wheel and Casing Structures Under Transient Thermal and Centrifugal Loads
Authors: Hattori T. , Toriya H. 
Published: March 2021

Abstract
Transient thermal and centrifugal loads on turbomachinery rotors have increased with recent increases in gas temperatures and tip speeds. Rotor weights must be decreased to improve rotor dynamics and to reduce bearing loads. Moreover, blade tip clearance must be decreased to improve aerodynamic efficiency. An optimum design technique offering the lightest possible wheel shape under specified stress and clearance limits is therefore required.
This paper introduces an optimum design system developed for turbo-machinery rotors. Sequential linear programming is used in the optimizing process, and non-steady-state thermal analyses of wheels and casings are performed by numerically analyzing multi-ring models. Stress and deformation analyses of these wheels and casings are performed by using Donath’s method with the same multi-ring model. This optimum design program is applied to the design of multistage axial flow compressor wheels.
An Alternative Approach to Mechanical Advantage for the Analysis of a Multiple-Input Multiple-Output Mechanical Device
Authors: Ogot M. M. , Gilmore B. J. 
Published: March 2021

Abstract
The design efficiency of mechanical systems has traditionally been measured via mechanical advantage (MA) which relates the amount of force exerted at the output to the corresponding force applied at the input. MA has been confined to single-input single-output devices, and only recently to single-input multiple-output port devices. This paper presents an alternative approach to MA. The classical definition of MA required the input force to do work on the mechanism, and the output force to be worked on by the mechanism. However this may cause problems where the external loads flip back and forth between doing work to and being worked on by the mechanism at different points in the cycle. This paper overcomes this difficulty by considering the input force as that applied by the mechanism actuator, and the output force to be the external or applied load. With these definitions, a general expression for MA applicable to multiple-input, multiple-output port mechanisms is presented.
Attributed Graph Model for Geometric Tolerancing
Authors: Shah Jami J. , Zhang Bing-Chun 
Published: March 2021

Abstract
The development of a face-based attributed graph structure for modeling geometric tolerances is described here. The structure, designated as the DTF graph, provides an integrated view of the dimensioning scheme, dimensions, tolerances, features, and datums. In the current version of the DTF model, all ANSI Y14.5M tolerance classes are supported, except profile tolerances. Edge related tolerances (straightness, circularity) are supported by derived face intersections. Other tolerances, and datum reference frames, are supported as face attributes or attributes of the DTF graph. The tolerance model is compatible with commonly used hybrid CSG-Brep solid modelers and has the property of uniqueness for any dimensioning scheme. Applications of the DTF Graph include: detection of over and under-constrained dimensions, automatic re-dimensioning if the designer changes the dimensioning scheme, and automatic discovery of dimension-tolerance stack-up loops.
Geometric Design and Fabrication of Developable Bezier Surfaces
Authors: Bodduluri R. M. C. , Ravani B. 
Published: March 2021

Abstract
In this paper we study Computer Aided Geometric Design (CAGD) and Manufacturing (CAM) of developable surfaces. We develop direct representations of developable surfaces in terms of point as well as plane geometries. The point representation uses a Bezier curve, the tangents of which span the surface. The plane representation uses control planes instead of control points and determines a surface which is a Bezier interpolation of the control planes. In this case, a de Casteljau type construction method is presented for geometric design of developable Bezier surfaces. In design of piecewise surface patches, a computational geometric algorithm similar to Farin-Boehm construction used in design of piecewise parametric curves is developed for designing developable surfaces with C2 continuity.
In the area of manufacturing or fabrication of developable surfaces, we present simple methods for both development of a surface into a plane and bending of a flat plane into a desired developable surface. The approach presented uses plane and line geometries and eliminates the need for solving differential equations of Riccatti type used in previous methods.
The results are illustrated using an example generated by a CAD/CAM system implemented based on the theory presented.
Numeric-Symbolic Approach for Dynamic Modelling of Robotic Manipulators
Authors: Fan Shou-wen , Xu Liju , Chen Yong 
Published: March 2021

Abstract
A simple numeric-symbolic method for dynamic modelling of robotic manipulators is proposed in this paper. Problem of deriving model matrix elements is transformed into problem of solving for driving force and driving torque under specified condition by recursive dynamic equations. Expressions of reaction force in arbitrary joint in numeric-symbolic form are also derived. Corresponding software which can recognize and manipulate symbols is developed and can be used to generate model and real-time code of robotic dynamics.
Parametric Design of Low Lateral Force Rollers for Belt Loop Drives
Authors: Hoeltzel David A. , Quadracci H. Richard , Castelli Vittorio 
Published: March 2021

Abstract
Belt loops supported by rollers commonly appear in xerographic type copying machines. Recently, rollers have been designed with special mechanical features employing a series of stacked annular discs mounted on a solid drive shaft. This configuration reduces the transverse forces acting on the belt due to edge guidance, and provides a method of belt control which eliminates the need for costly active belt steering servo systems. Rollers of this type are referred to as low lateral force (LLF) rollers. The addition of these lateral load inhibiting features necessitates that the rollers be carefully scrutinized for buckling and deformation, thereby ensuring accurate belt control for high quality xerographic copying.
A parameterized finite element model of a LLF roll has been developed. The results acquired from the model are presented in dimensionless form in terms of the physical variables that describe the geometric parameters of the discs comprising the roller: thickness, inner and outer radii and belt contact angle. Dimensionless forms for the buckling belt tension and the circumferential and axial stiffnesses of the discs are also evaluated and displayed against the dimensionless geometric parameters, using contour plots for belt contact angles of 45°, 90°, 135° and 180°. These plots have been employed in practical design calculations for the sizing of LLF rolls.
Direct Differential Kinematics of Hybrid-Chain Manipulators Including Singularity and Stability Analyses
Authors: Xu Yong-Xian , Kohli Dilip , Weng Tzu-Chen 
Published: March 2021

Abstract
A general formulation for the differential kinematics of hybrid-chain manipulators is developed based on transformation matrices. This formulations leads to velocity and acceleration analyses, as well as to the formation of Jacobians for singularity and unstable configuration analyses. A manipulator consisting of n nonsymmetrical subchains with an arbitrary arrangement of actuators in the subchain is called a hybrid-chain manipulator in this paper. The Jacobian of the manipulator (called here the system Jacobian) is a product of two matrices, namely the Jacobian of a leg and a matrix M containing the inverse of a matrix Dk, called the Jacobian of direct kinematics. The system Jacobian is singular when a leg Jacobian is singular; the resulting singularity is called the inverse kinematic singularity and it occurs at the boundary of inverse kinematic solutions. When the Dk matrix is singular, the M matrix and the system Jacobian do not exist. The singularity due to the singularity of the Dk matrix is the direct kinematic singularity and it provides positions where the manipulator as a whole loses at least one degree of freedom. Here the inputs to the manipulator become dependent on each other and are locked. While at these positions, the platform gains at least one degree of freedom, and becomes statically unstable. The system Jacobian may be used in the static force analysis. A stability index, defined in terms of the condition number of the Dk matrix, is proposed for evaluating the proximity of the configuration to the unstable configuration. Several illustrative numerical examples are presented.
Direct Position Kinematics of the 3-1-1-1 Stewart Platforms
Authors: Husain Muqtada , Waldron Kenneth J. 
Published: March 2021

Abstract
In this work, a closed form solution for the direct position kinematics problem of a special class of Stewart Platform is presented. This class of mechanisms has a general feature that the top platform is connected to the six limbs at four locations. Three limbs connect at one location and the remaining limbs connect to the top platform singly at three separate locations. The base platform is connected at six different locations as is the case in the general platform. This particular class of mechanism is termed as 3-1-1-1 mechanism in this paper. It has been shown that there are a maximum of sixteen real assembly configurations for the direct position kinematics problem. This has been verified using a geometric argument also. The numerical example solved in this paper demonstrates that it is possible to obtain a set of solutions which are all real.
Inverse Kinematics of General 4R2P, 3R3P, 4R1C, 2R2C, and 3C Serial Manipulators
Authors: Kohli Dilip , Osvatic Michael 
Published: March 2021

Abstract
This paper presents a solution to the inverse kinematics problem for 4R2P, 3R3P, 4R1C, 2R2C and 3C manipulators of general geometry. The method used to solve these is based on a technique recently presented by the authors for solving the inverse kinematics of general 6R and 5R1P manipulators. In the 6R and 5R1P cases, the method initially starts using 14 linearly independent equations where as for the 4R2P, 3R3P, 4R1C, 2R2C and 3C manipulator only 3, 6, 7 or 10 linearly independent equations are required, depending on the case. Through the use of a linearization and dialytic elimination method all 4R2P, 3R3P, 4R1C, 2R2C and 3C cases are reduced to equating to zero the determinant of a matrix whose elements are linear in the tangent of a half angle of a joint variable. The size of this matrix is (8 × 8) for all 4R2P manipulators, (2 × 2) for all 3R3P and 3C manipulators, (16 × 16) for 4R1C manipulators, (4 × 4) for RCRC and CRCR manipulators and (8 × 8) for the remaining 2R2C manipulators providing 8th, 2nd, 16th, 4th and 8th degree inverse kinematic polynomial respectively. Thus, the determinant equated to zero gives us the characteristic equation of the degree expected. The unique form of the matrix allows us to obtain the solution by solving an eigenvalue problem. Many variations of the 4R2P, 3R3P, 4R1C, 2R2C and 3C manipulators are presented and the solution methodology is illustrated by several numerical examples.
Design Improvement of Manipulators by Minimizing Shaking Force/Moment and Driving Torques
Authors: Husain Muqtada , Mallik Akhtar K. , Ghosh A. 
Published: March 2021

Abstract
In this work, an algorithm for design improvement of open loop manipulators, after allowing for the necessary trade-offs among the maximum shaking force, shaking moment and the driving torques is presented. The improved design is attempted by only proper mass distribution of the links for the given kinematic structure and link masses. A min-max optimization problem, considering the worst configuration, is formulated via closed form expressions of the dynamical quantities derived by using Newton-Euler approach. The procedure, though applicable in general, is illustrated through the design of the arm structure of a PUMA 560 manipulator. This developed procedure will also be very helpful in the mechanical design of any new manipulator arm.
Optimal Synthesis and Analysis of a New Leg Mechanism: The Planetary Gear Leg
Authors: Chen Ning-Xin , Song Shin-Ming 
Published: March 2021

Abstract
The leg mechanism of a walking machine has a strong influence on the performance of the machine. A successful leg mechanism should be energy efficient, compact in size, strong and simple. In order to achieve good energy efficiency, a walking machine leg should be able to generate an exact or approximate straight line at the foot with only one driving actuator. This paper deals with the synthesis and analysis of a new leg mechanism — the planetary gear leg mechanism. Four types of planetary gear legs are studied. By the SUMT optimization method, a 20 inch tall leg is able to generate an approximate straight line trajectory with a maximum deviation of 0.12805 inches in a 20 inch stroke. The direct and inverse kinematics and velocities of the legs are analyzed. Also, the distribution of actuator force/moment during walking are studied. The results show that this leg design has great potential to be used as a practical walking machine leg.