bluuebunny/crossref_metadata_2025 huggingface dataset:
Preclinical Evaluation of Orthopaedic Implants
Authors: Piotrowski G. , Butler J. H. , Richardson D. C.
Published: January 2010

The Medical Device Amendments to the Food, Drug, and Cosmetics Act mandates that substantially new devices be subjected to study and testing prior to the commencement of clinical trials. The proposed outline for preclinical analysis, testing, and evaluation of orthopaedic implants is intended to guide the designer in defining what the limits of understanding are and, within those limits, to minimize the risk to implant recipient. The process of design qualification and verification is broken down into seven major steps: Problem Definition, Underlying Assumptions, Material Selection, Engineering Analysis, Correlation of Demand to Capabilities, Analytical Estimate of Performance and Experimental Verification of Performance. The discussion of each of these topics focuses on the type of information needed for each activity. Thus, these guidelines present a framework for the rational innovation and design of orthopaedic implants which minimizes the risk to patients involved in clinical trials.
Design and Testing of a Child’s Crutch with Conservative Energy Storage
Authors: Shoup T. E.
Published: January 2010

This paper describes the design of a new type of forearm crutch that features a conservative form of energy storage. Energy stored by the crutch during an early portion of the gait cycle is returned to the user later in the gait cycle. The results of experimental tests of the new crutch by children ages 7-12 years are presented, and evaluative conclusions are presented.
Reliability and Optimal Replacement via Coefficient of Variation
Authors: Pandit S. M. , Shiekh A. K.
Published: January 2010

The paper presents an approach to obtaining reliability and optimal replacement policies at different operating conditions, based on limited data at one operating condition. Guidelines for the choice of a distribution based on the behavior of sample functions of deterioration processes such as wear and fatigue are provided. The importance of the coefficient of variation is delineated to show how it provides a dimensionless format of the distributions and optimal replacement strategies. Simple graphical solutions of the otherwise complicated optimal replacement equations are illustrated by numerical examples based on experimental data in diverse forms from the areas of cutting tools and fatigue failures.
Design of Vibratory Systems with Aid of Dimensional Analysis
Authors: Hundal M. S.
Published: January 2010

The paper presents the use of dimensional analysis as an aid in the design of dynamic systems. Basic theory of dimensional analysis is discussed. Two examples are given: (1) a two degree of freedom vibrating system and (2) a flexible rotor which is flexibly supported at its ends. Choice of suitable non-dimensional parameters is discussed. A digitial computer program is described which generates all of the possible sets of non-dimensional parameters for a given problem.
Methods of Synthesis and Analysis for Hypoid Gear-Drives of “Formate” and “Helixform”—Part 3. Analysis and Optimal Synthesis Methods For Mismatch Gearing and its Application For Hypoid Gears of “Formate” and “Helixform”
Authors: Litvin F. L. , Gutman Y.
Published: January 2010

In this third and final part are proposed: (a) methods for analysis and optimal synthesis of mismatch gearing, (b) application of those methods for the analysis and synthesis of hypoid gear-drives generated by “Formate” and “Helixform” methods. In the previous parts, machine settings for the member-gear and the pinion of the Hypoid gear-drive were obtained. Use of these settings guarantee: (a) that the gear surfaces will be in tangency at a previously chosen point M, (b) that the conditions of meshing will be favorable at the point M and in its vicinity. But it is necessary to provide favorable conditions of meshing in the whole area of meshing. Methods proposed in this part permits achievement of those mentioned aims: (a) the analysis of gearing permits collection of the necessary information of meshing conditions in the whole area of meshing, (b) the optimal synthesis permits improvment of the conditions of meshing by variation of some parameters of pinion machine settings.
Tooth Bearing Analysis and Surface Durability of Symmetrical Conformal Gears
Authors: Kasuya K. , Nogami M. , Matsunaga T. , Watanabe M.
Published: January 2010

Tooth bearing of addendum modified symmetrical conformal gears is analyzed and surface durability of the gear is compared to that of non-modified gear experimentally. It is found that the influence of the center distance error on the load carrying capacity and the tooth bearing addendum modified gearing is less than that in conventional symmetrical conformal gearing.
Kinematic Efficiency of Non-Circular Geared Transmissions
Authors: Ferguson R. J. , Kerr J. H.
Published: January 2010

Infinitely-variable transmissions of high efficiency can be made using non-circular gears combined in function generators. The efficiency of a function generator depends on the gear parameters, the ratio of the differential, and the direction of power flow. The paper shows how the factors influence the total gear meshing losses and explain how efficiency is calculated. No-load losses are not included.
Finite Element Analysis of Hydraulic Cylinders
Authors: Ravishankar N.
Published: January 2010

A method of analysis which permits the investigation of stresses and deflections in a hydraulic cylinder, using a finite element analytical model, is presented. The hydraulic cylinder is modeled as an assemblage of space frame elements with a fictitious rotary spring at the gland to consider the effect of seals and bearings at the rod-cylinder interface.
Rotating Elasto-Plastic Interference Fits
Authors: Kollmann F. G.
Published: January 2010

By an elasto-plastic design the transferable torque of an interference fit can be increased significantly. In high-speed applications the initial contact pressure is reduced by the centrifugal body force. A fit having a full shaft and equal elastic constants of shaft and hub material is considered. Using Tresca’s yield criterion an analytical solution determining the dependence of contact pressure on angular velocity is derived. All formulae necessary for design of fits are presented. Numerical results are given and conclusions for practical applications of rotating elasto-plastic interference fits are drawn.
Technology Transfer in the Determination of Torque Characteristics of R4A Ball Bearings at High Speeds With Radial Load
Authors: Mabie H. H.
Published: January 2010

Torque-speed curves are presented for R4A ball bearings with one radial load and with oil, grease, and solid-film lubrication. These curves are reproduced with permission from Sandia Corporation, Albuquerque, New Mexico. Also included are several torque curves for R4 bearings for comparison with those for R4A bearings.
Dynamic System Response Technology Transfer Via Computer Modeling
Authors: Mitchell L. D. , Mitchiner R. G.
Published: January 2010

Traditionally the mechanical engineering design area of the mechanical engineering discipline has concerned itself with static design concepts. Recently, many university mechanical engineering curricula have placed a dynamics sequence in the mechanical design course path. This has had two results. First, the former graduates having little background in dynamic design concepts need to have a technology transfer effort focused upon them. Second, the current university student finds the understanding of highly mathematical, multiple degree-of-freedom models of real systems almost incomprehensible. This paper presents a proposed partial solution to the technology transfer problems above. A computer modeling program has been developed that computes the steady-state response of a multi-degree-of-freedom system. Magnitude and phase of the response is graphically presented for combinations of masses, stiffnesses, viscous dampers, and/or structural dampers in any interconnection scheme. The algorithm has been used to model real-world engineering problems that would normally elude the undergraduate student and many practicing engineers. These same modeling efforts can be used to stimulate the practicing engineer to relate to these solutions and their real-world significance.
Mathematical Formulation of Cooling Water Flow Rates for High Speed Continuous Slab Caster
Authors: Singh Y. P.
Published: January 2010

In high speed continuous steel slab castings machine, the partially solidified strand emerging out from the bottomless mold is cooled to complete solidification by means of water sprays arranged through its metallurgical length. The cooling water flow rates are dependent on slab size, grade of steel cast, working length of mold, casting speed, water pressure, spray nozzles and their location in the strand support system of the caster. In this paper an analytical method to predict the spray cooling water flow rates is presented. A least square polynomial is found which best describes extensive data of cooling flow rates obtained from high speed continuous steel slab caster at Linz, Austria. Polynomial curves for various slab sizes, grades of steel cast and casting speeds have been determined using the actual water flow rates data and the developed least square technique. The technique developed in this paper is general and can be used for determination of cooling flow rates of any type of continuous steel casting machine.
Effects of Moving Speeds of Dynamic Loads on the Deflections of Gear Teeth
Authors: Nagaya K. , Uematsu S.
Published: January 2010

For the dynamic response problems of gear teeth, the dynamic loads which act upon the gear teeth should be considered as a function of both the position and the moving speed. In previous studies, the effects of the moving speed have not been considered. In this paper the effects of the moving speed of dynamic loads on the deflection and the bending moment of the gear tooth are investigated. The results are obtained from the elastodynamic analysis of the tapered Timoshenko beam.
Constrained Fatigue Life Optimization of a Nasvytis Multiroller Traction Drive
Authors: Coy J. J. , Rohn D. A. , Loewenthal S. H.
Published: January 2010

A contact fatigue life analysis method for multiroller traction drives is presented. The method is based on the Lundberg-Palmgren analysis method for rolling element bearing life prediction, and also uses life adjustment factors for materials, processing, lubrication, and effect of traction. The analysis method is applied in an optimization study to the multiroller traction drive, consisting of a single-stage planetary configuration with two rows of stepped planet rollers of five rollers per row. The drive was approximately 25 centimeters in diameter by 11 centimeters long, having a nominal ratio of 15:1. The theoretically predicted drive life was 2510 hours at a nominal continuous power and speed of 74.6 kW (100 hp) and 75,000 rpm.
Simplified Fatigue Life Analysis for Traction Drive Contacts
Authors: Rohn D. A. , Loewenthal S. H. , Coy J. J.
Published: January 2010

A simplified fatigue life analysis for traction drive contacts of arbitrary geometry is presented. The analysis is based on the Lundberg-Palmgren theory used for rolling-element bearings. The effects of torque, element size, speed, contact ellipse ratio, and the influence of traction coefficient are shown. The analysis shows that within the limits of the available traction coefficient, traction contacts exhibit longest life at high speeds. Multiple, load-sharing arrangements have an advantageous effect on system life, torque capacity, power-to-weight ratio and size.
A Simple Thermal Correction for Large Spin Traction Curves
Authors: Tevaarwerk J. L.
Published: January 2010

Presented in this paper is a simple design technique, based upon energy equivalence methods, to predict the thermally influenced large spin traction curves from a single nonspin large slip traction curve. The performance characteristics of variable speed traction drives is very closely linked to the rheological behavior of the fluid in the contact. At moderate values of spin the traction force can be predicted quite accurately from the Johnson and Tevaarwerk model. Their model is completely isothermal in nature. As the spin increases a definite discrepancy occurs between predicted and measured data and this discrepancy grows with increasing spin. Elastic effects in the fluid are negligible at these larger spin values and therefore the shearing is purely dissipative in nature. The observed discrepancy is thought to be caused by the heating of the material in the contact and the loss of limiting strength accompained by this. The model presented in this paper reduces the discrepancy between isothermally predicted spin traction and the thermally affected traction.
Optimum Balancing of Combined Pitching and Yawing Moments in High-Speed Machinery
Authors: Freudenstein F. , Macey J. P. , Maki E. R.
Published: January 2010

Traditional methods of balancing shaking forces and shaking moments in highspeed machinery are well developed and documented. In the case of nonstandard configurations, however, the analytical expressions become complicated and unwieldy. The minimization of pitch and yaw can be a tedious process and difficult to accomplish using conventional techniques. In this study we derive the equations for minimizing any order combined pitching and yawing moments in high-speed machinery by counterweighting the driveshaft or a shaft geared to the driveshaft. The equations, which are algebraic, are given directly as a function of the harmonic coefficients of pitch and yaw and apply to any plane machine configuration. The results yield an optimized configuration having the minimax sum of the amplitudes of pitch and yaw of any order, or the minimax vector sum of pitch and yaw of any order. The concept of balancing efficiency is introduced and the theory is illustrated by numerical examples.
Residual Vibration Criteria Applied to Multiple Degree of Freedom Cam Followers
Authors: Wiederrich J. L.
Published: January 2010

The vibration characteristics of a cam motion are generally presented by plotting the single degree of freedom residual vibration as a function of normalized operating speed. In this paper it is shown that by applying the methods of modal analysis, these residual vibration characteristics can be extended to the characterization of the vibration response of a multiple degree of freedom cam follower system.
Stress Fluctuation in High Speed Mechanisms
Authors: Yang A. T. , Pennock G. R. , Hsia L. M.
Published: January 2010

In this paper analytical expressions are derived which describe the nature of the stress fluctuation induced in a member of a high speed mechanism. For design applications a harmonic analysis of the stress fluctuation is presented and the results are expressed in a non-dimensional form. For illustrative purposes, the analysis is centered on the coupler link of the well-known slider-crank mechanism.
Probabilistic Models in Computer Automated Slider-Crank Function Generator Design
Authors: Schade G. R.
Published: January 2010

Using deterministic algebraic techniques, it is possible to synthesize function generator mechanisms which can produce extremely small structural error. However, due to normal variations in dimensions inherent in the manufacture of the components of the mechanism, there may be an extremely low probability of assembling a mechanism which approaches the accuracy predicted by a deterministic representation of the mechanism. This paper presents a probabilistic model of the slider-crank function generator, and a method of optimization of this model. Mechanisms are optimized on the basis of both deterministic and probabilistic models, and the resulting optima are compared by computer simulated production. If the statistical properties of the production techniques are known, it is possible to significantly increase the production yield of acceptable mechanisms by using the probabilistic model for design optimization.
Application of Orthotropic Plate Theory to Windmill Blade Design
Authors: Rubin C.
Published: January 2010

The windmill blade is treated as a semi-infinite orthotropic wedge with free-free boundary conditions. A closed form solution for the deflections and stresses is obtained as a function of the loading. The loading may be quite general. Results for three different materials which are commonly used for windmill blades (aluminum, sitka spruce, and fiberglass) are obtained. Applications also include ribbed, corrugated, and layered structures. In addition, other types of boundary conditions may be used to obtain solutions to a wide variety of other orthotropic plate problems.
Latest Developments in Power Transmission
Authors: Tucker A.
Published: January 2010

Major advances have occurred within this past century in the technology of power transmission and gearing. This fact was amply demonstrated by the numerous technical papers presented at the International Symposium on Gearing and Transmissions in 1972 at San Francisco, at the Design Engineering Technical Conference in 1977 at Chicago, and at the Century 2 International Power Transmissions and Gearing Conference in 1980 at San Francisco. Many areas of gear technology were covered such as Gear Applications, Geometry, Materials, Metallurgy, Manufacturing Loads and Stresses, Tribology, Traction Drives, etc. A few of the developments, which may be considered as advancing the state-of-art of power transmission, will be described here.
The Kinematics of Crossed Helical Gears
Authors: Colbourne J. R.
Published: January 2010

A study is made of the motion of crossed helical gears. Exact expressions are derived for the position of the contact point on each gear and for the sliding velocity, both as functions of gear position. It is shown how to calculate the angular positions of each gear at the beginning and end of contact, and hence the contact ratio. And finally, expressions are given for the tooth force and bearing reactions, which are only approximate, in that the effect of friction is neglected.
Experiments on the Dynamic Behavior of a Supercritical Rotor
Authors: Botman M. , Samaha M. A.
Published: January 2010

Tests have been performed on supercritical rotors to determine the sensitivity to unbalance and the suitability of balancing techniques. Results are presented for a rotor with an overhanging disk and supported on two rolling element bearings in series with squeeze-film dampers. The rotor has two flexural modes with high relative strain energy in the speed range up to 55,000 rpm. After completion of the balancing exercise the rotor could be run to maximum speed and was found to be stable and free from half-frequency whirl instability, depending on the oil inlet pressure of the dampers. Pressurization of the dampers and increasing the clearance of the dampers had a very desirable effect on the stability behavior and the unbalance response.
The Spine of the Root Locus for the Viscous Damper
Authors: Stern D.
Published: January 2010

At present the optimization of a vibration isolator is performed in either the time domain or the frequency domain. A new approach, for optimization in the S-plane, is outlined and performed for the viscous damper. Optimization of the viscous damper in the S-plane results in a line that is defined as the spine of the root locus. Transformations are required between the S-plane and either the frequency domain or the time domain, therefore, time and frequency response plots are included for the spine damper. Two examples are used to illustrate the application of the root locus for single mass and multi-mass models.
Bending of an Annularly Loaded Square Plate With a Central Circular Hole
Authors: Oja L. K. , Kinzel G. L. , Leissa A. W.
Published: January 2010

Although uniformly loaded square plates with round holes are analyzed in several references, a systematic approach to the analysis for a ring load does not appear to have been presented before. As in the case of the uniform load, the exact solution to the plate bending problem for an annular load about a central circular hole cannot be developed in closed form; however, accurate approximate methods can be developed. The method employed in this paper uses least-squares point-matching for the boundary conditions along the straight edges and the singularity-function approach for the radially discontinuous loading conditions. Deflection and bending-moment results in the form of curves are presented for selected ratios of hole diameter to plate size and for different annular loading conditions. Both simply supported and clamped boundaries at the outer edge are considered while the inner edge is assumed to be free.
The Application of Reliability Methods to Tolerancing
Authors: Parkinson D. B.
Published: January 2010

Techniques which have been developed to estimate failure probability in reliability analysis are here applied to problems associated with the tolerancing of the dimensions of manufactured components. In particular, a procedure is described which permits, for the general nonlinear problem, the deduction of an estimate of the frequency with which a set of components will fail to assemble together to the design specification. The method may also be used at the design stage to adjust the relative size of tolerances on different dimensions and to permit the relaxation of tolerances to the maximum degree commensurate with a required level of assurance of correct assembly. The calculations required are relatively simple and do not require the use of simulation techniques on a large digital computer. The application of the method described is illustrated by means of examples.
On the Kinematics of the Closed Epicyclic Differential Gears
Authors: Willis R. J.
Published: January 2010

The epicyclic differential gear has been known in modern times since 1575 when it appeared as a mechanism in a clock. Artifacts from an ancient shipwreck prove that it was known to the ancient Greeks at least 100 hundred years before Christ. The methods of kinematic analysis by either the relative angular velocity method or the instant center and linear velocity method, as given in the literature, are oriented toward specific solutions rather than general ones; they do not readily allow for parametric trend studies and they require a degree of imagination and intuition which may well be beyond the capabilities of those who are not practitioners of the art. The discussed methodology defines simple and compound epicyclic gears in terms of the overall ratio of a geometrically similar planetary gear. The kinematic analysis is derived in general terms for both the simple and compound epicyclic gear. It is shown that location of the point of zero tangential velocity of the velocity triangle relative to the system datum governs the characteristics of the gearset and whether it will perform as a differential gearset, or as a solar, star, or planetary gear. Simple mathematical relationships are given which define the proportions of the component gears, their speeds (rpm) and directions of rotations, and the resulting power splits. The formulas may be incorporated into simple computer programs oriented toward specific design requirements.
Grinding Wheel Profile for Hob Relief Grinding
Authors: Simon V.
Published: January 2010

In this paper a method is described for the calculation of the dished and pencil grinding wheel profiles for relief grinding of hobs for manufacturing spur, helical, and worm gears. Archimedean, convolute, involute, and ground worm gear drives are dealt with. For the purposes of control of the calculated grinding wheel profiles and of the determination of the generation error in the case of the profile curve approximation to a straight-line or a circular arc, the method contains the calculation of the hob tooth profile, relief ground with a grinding wheel of the calculated or approximated axial profile.
Surface Geometry of Circular Cut Spiral Bevel Gears
Authors: Huston R. L. , Coy J. J.
Published: January 2010

An analysis of the surface geometry of spiral bevel gears formed by a circular cutter is presented. The emphasis is upon determining the tooth surface principal radii of curvature of crown (flat) gears. Specific results are presented for involute, straight, and hyperbolic cutter profiles. It is shown that the geometry of circular cut spiral bevel gears is somewhat simpler than a theoretical logarithmic spiral bevel gear.
Dynamic Analysis of Mechanical Systems With Intermittent Motion
Authors: Wehage R. A. , Haug E. J.
Published: January 2010

A method is presented for dynamic analysis of systems with impulsive forces, impact, discontinuous constraints, and discontinuous velocities. A method of computer generation of the equations of planar motion and impulse-momentum relations that define jump discontinuities in system velocity for large scale systems is presented. An event predictor, working in conjunction with a new numerical integration algorithm, efficiently controls the numerical integration and allows for automatic equation reformulation. A weapon mechanism and a trip plow are simulated using the method to illustrate its capabilities.
Constructive Geometry in Three Dimensions for Computer-Aided Design
Authors: Sharpe R. J. , Thomas P. J. , Thorne R. W.
Published: January 2010

Three dimensional construction techniques are described along with the detailed description of several derivations. The resultant algorithms allow construction of points, lines, and conics directly in 3-space. These pieces of geometry are constructed relative to existing lines, conics, and splines which are represented as parametric rational cubics. The generality of these algorithms allows a single routine to handle construction relative to all curve types in the system. This characteristic reduces the amount of code and thus the implementation and maintenance costs of the CAD system. These techniques are being incorporated into a Computer-Aided Design system.
Monotonicity Analysis in Optimum Design of Marine Risers
Authors: Papalambros P. , Bernitsas M. M.
Published: January 2010

The optimal design of marine risers used for drilling and production of oil in offshore operations is studied. The optimization problem is formulated on a two-dimensional model for bending of circular tubular beams under tension and internal and external static pressure. A general polynomial expression describes the external hydrodynamic loads. Monotonicity analysis is used to identify active constraints, determine design rules, and reduce the size of the problem.
The Optimal Tolerance Assignment With Less Than Full Acceptance
Authors: Michael W. , Siddall J. N.
Published: January 2010

This paper proposes an approach that integrates the relationship between design and production engineers through the theory of nonlinear optimization. It attempts to cope with the problem of optimally allocating tolerances in a manufacturing process. The upper and lower limits of the random variables of an engineering system are allocated so as to minimize production cost, with allowance for the system scrap percentage. The approach is illustrated by an example, and the general mathematical theory is also provided. An important distinction between the design and the manufacturing scrap is introduced, and the cell technique is utilized to estimate efficiently the system scrap.
A Computer Method for the Finite Displacement Problem in Spatial Mechanisms
Authors: Ta´rrago J. A. , Serna M. A. , Bastero C. , Garci´a de Jalo´n J.
Published: January 2010

In this paper, a new method for the numerical solution of the finite displacement problem in spatial mechanisms with revolute (R), cylindrical (C), spherical (S), and prismatic (P) pairs is presented. It is based on the use of special points’ coordinates as Lagrangian coordinates of the mechanism. The kinematic constraint equations are imposed as constant distances, areas, and volumes of segments, triangles, and tetrahedrons determined by those points. The system of nonlinear equations is solved via the Gauss-Newton variation of the Least Squares Method. Finally, three examples are presented in which the good convergence properties of the method can be seen.
A Minimum Strain Energy Approach for Obtaining Optimal Unbalance Distribution in Flexible Rotors
Authors: Conry T. F. , Goglia P. R. , Cusano C.
Published: January 2010

A method is developed to design for optimal unbalance distribution in a rotor system which has elements that are assembled on the shaft and operates above the first critical speed. This method can also be used for computing the optimal selection of balance weights in specified planes for a rotor with a known distribution of unbalance—the classic balancing problem. The method is an optimization problem where the strain energy of the rotor and its supports are minimized subject to the constraints of the equations of motion of the rotor system at a particular balancing speed. The problem is a quadratic program that has a unique minimum.
Design Sensitivity Analysis of Frequency Response in Machine Structures
Authors: Yoshimura M.
Published: January 2010

Design sensitivity analysis of frequency response is required to improve and optimize dynamic characteristics of machine-tool and other machine structures. This paper presents design sensitivity coefficients of receptance-frequency-response evaluative functions. Design sensitivity analyses of the evaluative functions are conducted with respect to design variables of fundamental structural elements in machines. A numerical example of the design sensitivity coefficients is given using a simplified structural model of a lathe, and the relationships between design variable changes and improvements in evaluative functions are described.
Optimal Design of Semisubmersible Form by Minimizing its Motion in Random Seas
Authors: Akagi S. , Ito K.
Published: January 2010

For the purpose of improving the utilization of semisubmersibles such as oil rigs in random seas, an optimal design method is proposed to seek optimal forms with minimum motion against sea wave. In the optimal design method proposed here, the design objective is chosen to minimize the variance of heave motion amplitude of a semisubmersible oscillated by the sea wave in a working environment. By giving the displacement and the hull length of the semisubmersible as design conditions a priori, diameters of both hulls and each columns are determined optimally by using the quadratic programming technique. Through a numerical study on a semisubmersible design problem, it is ascertained that by the optimal design method a considerable improvement of the motion performance can be attained compared with the result given by the conventional design method.
Optimum Vehicle Suspension With a Damped Absorber
Authors: Ghoneim H. , Metwalli S. M.
Published: January 2010

The performance characteristics of vehicle suspension with optimum damped absorber are evaluated and compared with those of the pertinent optimized conventional and optimal active suspension system. A one-dimensional two-degree-of-freedom linear model, subjected to random guideway disturbance, is adopted. Optimization is based upon the rms tire-terrain normal force (a measure of controllability), constrained by the rms sprung mass acceleration (a measure of ride comfort). The rms rattle displacements between suspension components (a measure of dynamic excursion) and the power spectral density of the sprung mass acceleration (an addition measure of ride comfort) are evaluated to provide for additional vehicle performance criteria. The comparison demonstrates that both optimum damped absorber and optimal active suspensions, in general, improve vehicle performances. And, the optimal active is better when controllability is emphasized, but the optimum damped absorber suspension is superior when ride comfort is of prime importance.
Computer-Aided Interactive Graphical Design of Multispeed Gearboxes
Authors: Dhande S. G. , Gupta A.
Published: January 2010

In the present paper, a methodology for interactive, graphical design of multispeed gearboxes has been developed. The synthesis process covers the design of the kinematic structure of a gearbox including the selection of the speeds of all shafts and the selection of the number of teeth on various gears. In the proposed approach, it is possible to take into account several alternative kinematic structures of crossed, open, or mixed type. It is also possible to take into account discontinuities in the spectrums of speeds on intermediate shafts and also the inclusion of passive shafts. Based on the proposed methodology, a computer program has been developed and tested for the design of six- and eighteen-speed gearboxes. Results obtained have been presented.
Optimization of Elastic-Hardening Structures in Presence of Displacement Constraints
Authors: Cinquini C. , Contro R.
Published: January 2010

Optimum design, conceived as weight minimization, is formulated with reference to discrete (or discretized) physically nonlinear structures, under constraints concerning displacements and design parameter distributions. Optimality criteria and solving equations are achieved by means of the Lagrangian multiplier technique. A simple but significant example illustrates the method.
Determination of Joint Velocities of Robots by Using Screws
Authors: Sugimoto K.
Published: January 2010

The screw theory is applied to determination of joint velocities of robot arms. The method described in this paper can be directly used for the straight line trajectory control of existing industrial robots. Joint velocities are computed by taking inner products of two kinds of screws, one of which is an element of an orthogonal basis of the screw system composed of joint screws and another is the screw representing an instantaneous motion of an end effector. The computation can be performed during a sampling period while a robot is in motion.
Position Analysis of Spatial Mechanisms
Authors: Llinares J. , Page A.
Published: January 2010

In this paper matrix notation is used to develop a computational algorithm for position analysis of spatial mechanisms having revolute (R) and prismatic (P) pairs. Since all lower pairs are equivalent to some combination of R and P pairs, the method works for spatial mechanisms containing any lower pair. By using the method, spatial mechanisms are describable by simple equations which are easily programmable.
A Variational Formulation for the Nonlinear Finite Element Analysis of Flexible Linkages: Theory, Implementation, and Experimental Results
Authors: Thompson B. S. , Sung C. K.
Published: January 2010

A variational formulation is presented for the nonlinear finite element analysis of general planar mechanisms comprising assemblages of elastic bodies connected by revolute or sliding joints. A geometrically nonlinear theory is developed to describe the elastic behavior in the axial and flexural modes, and the model for the dynamical behavior includes inertial coupling terms linking the rigid-body and elastic kinematic motions. The formulation developed herein is employed to predict the elastodynamic response of experimental four bar linkages and slider crank mechanisms.
Optimal Tolerance Design of a Printer Actuator
Authors: Chen J. S.-C. , Wang S. , Zug P.
Published: January 2010

In this paper we describe an extension of an existing optimization technique to the tolerance design of a printer actuator mechanism. We provide the designer with a method for selecting optimal nominal design values for the parameters of a generalized system which allows maximum tolerance excursions away from the nominal design values and yet still maintains performance standards. The method uses an interactive linear-programming based design optimization algorithm to select optimal nominal parameter values and their associated maximal tolerances. We illustrate the method with a simple two-dimensional example. Finally we show the results from the tolerance optimization of a printer actuator which demonstrates the applicability of the theory to a real design problem.
Design Optimization of Machine-Tool Structures Considering Manufacturing Cost, Accuracy, and Productivity
Authors: Yoshimura M. , Takeuchi Y. , Hitomi K.
Published: January 2010

This paper proposes a multiphase design optimization method using simplified structural models in order to minimize manufacturing cost of machine-tool structures under constraints of machining accuracy, machining productivity, and local deformations of structural members. The manufacturing cost is divided into three components—material cost, welding cost, and machining cost, each of which is minimized in the multiphase optimization process. The method is demonstrated on a structural model of a double-column machine tool.
The Optimization of a HERF Machine When Subjected to Impact Loading
Authors: Vasconcelos H. F. , Taylor S.
Published: January 2010

The development of high energy-rate forming machines requires the prediction of the vibrational behavior and noise radiation at the design stage. An automatic optimization technique for minimizing the kinetic energy transmitted to the ringing modes of vibration is described. Structural, functional and dynamic constraints are included to ensure the feasibility of the optimum design. The technique is suitable for adaptation to other optimizing criteria and to other types of structure.
Coulomb Friction and Optimal Rocker Arm Ratio for High-Speed Cam Systems
Authors: Pisano A. P. , Chen Hong Tao
Published: January 2010

The operating speed of a high-speed cam system can be maximized by the proper choice of both kinematic and dynamic parameters of a lumped model. Considering rocker arm ratio as an unconstrained kinematic parameter and Coulomb friction as an unconstrained dynamic parameter, it was found that the camshaft speed at which toss occurred was characterized by several local extrema, all of which were sensitive to the presence of Coulomb friction. For a particular cam system and two separate cam lift curves, design charts have been developed to aid in the choice of optimal rocker arm ratio for maximum operating speed in the presence of Coulomb friction.
Fatigue Design of Racks for Jack-Up Units
Authors: Honda Hiroshi
Published: January 2010

The subject paper presents the methods and results of fatigue tests for both torch-cut and machined racks using 40.4 mm module and finite-element elastic stress analyses for these racks. Further, the results of the analysis of fluctuating jack load range distribution over a one-year period for a jack-up rig is presented. The author proposes a fatigue design method of racks for jack-up units based on the foregoing results. The proposed fatigue design method was compared with those of ASME Boiler and Pressure Vessel Code, DNV’s Classification Notes, and the draft proposal of ISO for the strength design of gears, resulting in the conclusion that a single conventional fatigue design method as presented by ASME, ISO and DNV is insufficient for the fatigue design of these racks.
Optimal Balancing of High-Speed Linkages Using Multiobjective Programming Techniques
Authors: Rao S. S. , Kaplan R. L.
Published: January 2010

The application of multiobjective optimization techniques to minimize the dynamic reactions of planar mechanisms is studied. A systems-oriented procedure, which can easily incorporate variable angular velocity input as well as joint friction and external loading, is used for the dynamic analysis of the mechanisms. Goal programming, goal attainment, and a combined bounded objective function/lexicographic method are outlined as solution procedures. These optimization methods are implemented using a computer program based on an exterior penalty function approach. An example four-bar linkage is considered for illustration and the results obtained with different methods of optimization are reportred. It is observed that the methods presented in this paper offer greater flexibility and wider application in the optimal balancing of high-speed linkages.
Application of the Vector-Network Method to Constrained Mechanical Systems
Authors: Li Tai-Wai , Andrews Gordon C.
Published: January 2010

The vector-network technique is a methodical approach to formulating equations of motion for unconstrained dynamic systems, utilizing concepts from graph theory and vectorial mechanics; it is ideally suited to computer applications. In this paper, the vector-network theory is significantly improved and extended to include constrained mechanical systems with both open and closed kinematic chains. A new formulation procedure is developed in which new kinematic constraint elements are incorporated. The formulation is based on a modified tree/cotree classification, which deviates significantly from previous work, and reduces the number of equations of motions to be solved. The dynamic equations of motion are derived, with generalized accelerations and a subset of the reaction forces as solution variables, and a general kinematic analysis procedure is also developed, similar to that of the dynamic formulation. Although this paper restricts most discussions to two-dimensional (planar) systems, the new method is equally applicable to 3-dimensional systems.
Dynamic Analysis of a Universal Joint With Manufacturing Tolerances
Authors: Chen Ching-Kong , Freudenstein Ferdinand
Published: January 2010

A dynamic analysis has been developed of a universal joint with manufacturing tolerances. The results, which represent an extension of the earlier work of Fischer and Freudenstein [2], permit the determination of bearing forces under high-speed operation in the design stage.
The Dynamic Modeling of Flexible Spatial Machine Systems With Clearance Connections
Authors: Dubowsky S. , Deck J. F. , Costello H.
Published: January 2010

An effective method is presented for modeling the full three-dimensional dynamics of high performance spatial machine systems, including the vibrations of their links, supporting structure and enclosures, and impacts in their connection clearances. The method combines four-by-four matrix modeling techniques with finite-element techniques. The system’s elements can be described in rich detail, including detailed models of the internal structure of the connections, yet the dynamic calculations are performed efficiently. The method is formulated for implementation on computer-aided design systems. Examples are presented.
Optimization of Antisymmetric Angle-Ply Strip for Maximum Strength Including Hygrothermal Effects
Authors: Adali S. , Nissen H.
Published: January 2010

The transverse failure load on an antisymmetrically laminated angle-ply strip is maximized with respect to fiber volume ratio. The failure load is determined using the Tsai-Hill failure theory based on initial ply failure criterion. Hygrothermal conditions and the presence of voids in the resin are taken into account in computing the material and strength properties from micromechanical relations. Numerical results are given for graphite, boron and E-glass fibers and the effects of hot-wet conditions and voids are investigated on the efficiency and the fiber content of the optimal designs. Sensitivity of the designs to changes in the design variable is graphically studied.
Dynamic Analysis of Three-Dimensional Mechanisms in “Natural” Coordinates
Authors: Garci´a de Jalo´n J. , Unda J. , Avello A. , Jime´nez J. M.
Published: January 2010

In this paper a new method for the dynamic analysis of three-dimensional mechanisms is presented. This method is based on the use, as mechanism coordinates, of Cartesian coordinates and components of some points and vectors rigidly attached to every element. With these coordinates the constraint equations are very easily formulated. A constant mass matrix has been derived for an element with two points and two vectors. Two simple and efficient methods to establish the dynamic equilibrium equations are presented. The use of the singular value decomposition is also included. Finally some comparative results are presented.
On the Maximum Value of the Maximum Degree of Kinematic Chains
Authors: Yan Hong-Sen , Harary Frank
Published: January 2010

One of the major steps in the development of a systematic design methodology for the creative design of vehicle mechanisms is to obtain all possible link assortments, and then to generate the catalogs of kinematic chains. If the generalized mathematical expressions for the maximum value M of the maximum number of joints incident to a link of kinematic chains with N links and J joints can be derived, the process of solving link assortments can be more systematic. Using elementary concepts of graph theory, we derived explicit relationships for M for two regions of the J-N plane.
Approximation of Computationally Expensive and Noisy Functions for Constrained Nonlinear Optimization
Authors: Free J. W. , Parkinson A. R. , Bryce G. R. , Balling R. J.
Published: January 2010

The use of statistical experimental designs is explored as a method of approximating computationally expensive and noisy functions. The advantages of experimental designs and function approximation for use in optimization are discussed. Several test problems are reported showing the approximation method to be competitive with the most efficient optimization algorithms when no noise is present. When noise is introduced, the approximation method is more efficient and solves more problems than conventional nonlinear programming algorithms.
Synthesis of Harmonic Motion Generating Linkages—Part I: Function Generation
Authors: Farhang K. , Midha A. , Bajaj A. K.
Published: January 2010

This paper deals with the first and higher-order function-generation problems in the synthesis of linkages with relatively small input cranks. Such linkages tend to produce nearly simple harmonic motions at the output members. Owing to this distinction, the generality of the conventional synthesis techniques is no longer applicable. Thus, in function generation, only harmonic functions of the input motion may be expected to be synthesized for output motions.
Simultaneous Structural and Control Design Using Constraint Functions
Authors: Starkey J. M. , Kelecy P. M.
Published: January 2010

A design technique is presented which modifies system dynamics by simultaneously considering control system gains and structural design parameters. Constraint functions are devised that become smaller as (1) structural design parameters and feedback gains become smaller, and (2) closed-loop eigenvalues migrate toward more desirable regions. By minimizing a weighted sum of these functions, the interaction between design performance and design parameters can be explored. Examples are given that show the effects of the weighting parameters, and the potential advantages of this technique over traditional pole placement techniques.
The Development and Application of Kinematic Icon and Inactive-Joint Concepts in Automated Mechanism Sketching
Authors: Wu L. , Pisano A. P.
Published: January 2010

An important step within the automated type synthesis process is the generation of graphical displays of proposed mechanisms which permit designers to visualize the candidates. In this paper, the concepts of kinematic icon and inactive joint have been developed and applied to the problem of automatically generating sketches of mechanisms, given only the kinematic structure. Each different link type is treated as a separate entity: an icon, with its own predefined graphical representation. Moving-link icons, (as opposed to icons of fixed links) have special properties defined according to the joint types on the adjacent links. The locations, sizes, and orientations of the icons depend on the locations of the joints whose coordintaes may be directly assigned (in simple cases) using joint placement procedures. However, because the icons are defined by assigning a specific graphical representation to groupings of joints, and not just single joint, not all joints can be directly assigned their coordinates and this other class of kinematic joint is defined as an inactive joint. The kinematic icon and inactive joint concepts make possible the sketching of mechanisms with more complicated joint types such as prismatics and gears, for the first time in a systematic manner.