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. In searching for an optimum by examining assignments of active constraints, one wishes to avoid assignments with no solution. A simple Maximal Activity Principle is stated to detect situations in which some subset of constraints has too few variables.
The principle is illustrated on a well-known weldment design problem. A finite-element-based method is developed and applied for geometrically nonlinear dynamic analysis of spatial mechanical systems. Vibration and static correction modes are used to account for linear elastic deformation of components. Boundary conditions for vibration and static correction mode analysis are defined by kinematic constraints between components of a system. Constraint equations between flexible bodies are derived and a Lagrange multiplier formulation is used to generate the coupled large displacement-small deformation equations of motion.
A standard, lumped mass finite-element structural analysis code is used to generate deformation modes and deformable body mass and stiffness information. An intermediate-processor is used to calculate time-independent terms in the equations of motion and to generate input data for a large-scale dynamic analysis code that includes coupled effects of geometric nonlinearity and elastic deformation. Two examples are presented and the effects of deformation mode selection on dynamic prediction are analyzed. This paper proposes a method for evaluating forced and self-excited vibrations at the design stage of machine-tool structural systems.
Cross modal flexibilities between the forced excited and the displacement pick-up points are analyzed. The relationships between the highest allowable values of receptance and vibrational displacement, and the static compliance and modal flexibility are clarified. Then the algorithms of the evaluative methods which use those analyses are given.
Using the proposed method, natural modes which must be disregarded in the evaluation of the characteristics can be determined, 1 even when directional orientations of the excited force at points in regard change greatly as a result of states of operations or cannot be definitely determined, and 2 even if damping properties are not clearly known. Designers can judge whether or not a given structural design has vibrational defects. The procedures of the evaluative method are exemplified with numerical examples. A general procedure is proposed for evolving the form of a density function that is consistent with the concept of subjective probability.
The procedure directly applies new data information to the updating of the form of a density function without imposing on it any theoretical distribution that could restrict its shape, and permits the direct use of judgment arising from real world experience. It is based on the simple concept that sample size is a measure of confidence in the shape of a density function.
The importance of probability in artificial intelligence is also dicusssed, and its essentially subjective nature is described. Procedures are briefly suggested. An algorithm is presented for the efficient constrained or unconstrained minimization of computationally expensive objective functions. The method proceeds by creating and numerically optimizing a sequence of surrogate functions which are chosen to approximate the behavior of the unknown objective function in parameter-space.
The Recursive Surrogate Optimization RSO technique is intended for design applications where the computational cost required to evaluate the objective function greatly exceeds both the cost of evaluating any domain constraints present and the cost associated with one iteration of a typical optimization routine. Efficient optimization is achieved by reducing the number of times that the objective function must be evaluated at the expense of additional complexity and computational cost associated with the optimization procedure itself.
Comparisons of the RSO performance on eight widely used test problems to published performance data for other efficient techniques demonstrate the utility of the method. 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.
Two examples of constrained actuator optimization are presented where up to eight design parameters are optimized. One example problem involves minimizing variations in the response time of a fuel injection control valve caused by manufacturing and assembly tolerances, while the other example deals with minimizing the response time of a high-speed gas sampling valve. In this investigation modal parameters frequency, damping, and mode shapes which are determined experimentally using parameter estimation techniques are employed to simulate and predict the dynamic behavior of flexible multibody systems which consist of interconnected rigid and flexible components.
The system differential equations of motion and algebraic constraint equations describing mechanical joints in the system are first identified using analytical techniques. Dynamic parameters such as mass, damping, and stiffness coefficients that appear in the system differential equations are then identified using a set of experimentally measured data. Mode shapes which are the result of the experimental identification are used to write the physical elastic coordinates of selected nodal points on the flexible body in terms of a reduced set of modal coordinates. The nonlinear differential and algebraic constraint equations are then written in terms of mixed sets of coupled reference and modal coordinates.
These equations are integrated numerically using a direct numerical integration technique coupled with Newton—Raphson type iterations in order to check on constraint violations. The formulation developed is numerically exemplified using a three-dimensional dune buggy vehicle model. A cam driving a single lumped mass through a massless, elastic, slider-crank follower linkage is considered. A technique is developed for synthesizing the cam profile to produce a desired output motion at a given design speed.
The procedure takes the elasticity and changing geometry of the linkage into account. Analysis equations are also derived to study the output motion at various speeds.
Theory of Mechanisms and Machines TMM
The equation of motion for the output link is found to be a Hill equation whose periodicity depends on the changing geometry of the mechanism. This paper presents the analysis and design of a robotic worktable with a structure based on two platforms connected by three four-bar linkages. The worktable has three rotational degrees-of-freedom and is designed for special motion generators, such as gyroscope calibration instruments and flight simulators. Of primary interest is the influence of the characteristics of a single four-bar linkage on the entire-motion characteristics of the worktable.
This involves an investigation of the effects of limit positions, rotatability of cranks, transmission-angle characteristics and the variation of design parameters of the four-bar linkages on the characteristics of the compound platform mechanism. Based on the analytical results, some physical insights are interpreted and general guidelines can be drawn on the design of this robotic worktable with prescribed motion characteristics.
The article deals with Geneva mechanisms driven with multiple cranks for the generation of multiple indexings with different index ratios during a cycle of motion. Both, Geneva-wheel mechanisms, and Geneva-slider mechanisms for the generation of rotary and linear motions with dwells, respectively, are considered. Design equations for both types of Geneva mechanisms are offered to synthesize the motion and dwell-time distributions, or the index ratio distributions, during a cycle of motion, and synthesize for the dimensions of the system.
Mechanism and Machine Theory
Partially irregular and completely irregular Geneva mechanisms are considered for both types, where the partially irregular Geneva mechanisms generate the same motion time but different dwell times for different indexings, while the completely irregular Geneva mechanisms generate different motion times as well as different dwell times for different indexings during a sequence of indexings.
Sequences of indexings during one cycle of motion during one rotation of the Geneva wheel, for example can be repeated several times. The uses of the design equations offered are illustrated with six industrial application examples. The following result for spherical four-bar mechanisms is proved: An alternate form of this result also is developed. Russia, , Saint-Petersburg, Polytechnicheskaya st.
Advances in Mechanical Engineering. Selected Contributions from the Conference "Modern Engineering: Lecture Notes in Mechanical Engineering. This book draws together the most interesting recent results to emerge in mechanical engineering in Russia, providing a fascinating overview of the state of the art in the field in that country which will be of interest to a wide readership. A broad range of topics and issues in modern engineering are discussed, including dynamics of machines, material engineering, structural strength and tribological behavior, transport technologies, machinery quality and innovations.
The book comprises selected papers presented at the conference "Modern Engineering: The authors are experts in various fields of engineering, and all the papers have been carefully reviewed. The book will be of interest to mechanical engineers, lecturers in engineering disciplines, and engineering graduates. See Web of Science: Dynamics of cyclic machines. Foundations of Engineering Mechanics. Springer Verlag, , XIX, p.
Mechanism and Machine Theory
Presents the modern methods of oscillation analysis in machines, including cyclic action mechanisms like linkage, cams, and steppers. Offers insight into problems of dynamic and especially to oscillations to engineers producing cyclic machines. Builds a bridge between the classic theory of oscillations and its practical application.
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This book focuses on modern methods of oscillation analysis in machines, including cyclic action mechanisms linkages, cams, steppers, etc. It presents schematization techniques and mathematical descriptions of oscillating systems, taking into account the variability of the parameters and nonlinearities, engineering evaluations of dynamic errors, and oscillation suppression methods. The majority of the book is devoted to the development of new methods of dynamic analysis and synthesis for cyclic machines that form regular oscillatory systems with multiple duplicate modules.
There are also sections examining aspects of general engineering interest nonlinear dissipative forces, systems with non-stationary constraints, impacts and pseudo-impacts in clearances, etc. The examples in the book are based on the widely used results of theoretical and experimental studies as well as engineering calculations carried out in relation to machines used in the textile, light, polygraphic and other industries.
Particular attention is paid to dynamic forecasting and engineering recommendations. Although it is intended for engineers and scientists who specialize in the field of machine dynamics, it will also be useful for graduate and postgraduate students. New Advances in Mechanisms, Transmissions and Applications: Mechanisms and Machine Science, Vol.
XII, - p. The aim of the workshop was to bring together researchers, scientists, industry experts and students to provide, in a friendly and stimulating environment, the opportunity to exchange know-how and promote collaboration in the field of Mechanism and Machine Science.
The topics treated in this volume are mechanism and machine design, biomechanics, mechanical transmissions, mechatronics, computational and experimental methods, dynamics of mechanisms and micromechanisms and microactuators.
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- Volume Issue 3 | Journal of Mechanical Design | ASME DC;
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History of Mechanism and Machine Science, Vol. VIII, - p. This book is composed of chapters that focus specifically on technological developments by distinguished figures in the history of MMS Mechanism and Machine Science. Biographies of well-known scientists are also included to describe their efforts and experiences, and surveys of their work and achievements, and a modern interpretation of their legacy are presented.
After the first two volumes, the papers in this third volume again cover a wide range within the field of the History of Mechanical Engineering with specific focus on MMS and will be of interest and motivation to the work historical or not of many. Topics treated include contributions on subjects such as new trends and experiences in mechanical engineering education; mechanism and machine science in mechanical engineering curricula; MMS in engineering programs, such as, for example, methodology, virtual labs and new laws.
All papers have been rigorously reviewed and represent the state of the art in their field. A commonly used practice in industry is the machining of sculptured part surfaces on a multi-axis numerical control NC machine. While this practice is vital, it is also a costly aspect of the surface generation process. After investing more than 40 years of research into the theory of part surface generation, the author of Generation of Surfaces: Kinematic Geometry of Surface Machining considers an approach that provides optimal machining while factoring in the lowest possible cost.
This second edition of the book the first edition http: The text is presented in three parts: The first part of the book provides an analytical description of part surfaces, details the principal elements of the theory of multi-parametric motion of a rigid body in E3 space, and defines applied coordinate systems. The second half introduces the theory of part surface generation, and includes an analytical description of contact geometry, while the final portion illustrates the potential development of highly effective part surface generation methods.
The author illustrates the most complex features of the book with examples, explains all of the results of analysis mathematically, and uses just one set of input parameters—the design parameters of the part surface to be machined. The book considers practical applications for part surface machining and cutting tool design.
Механизмы Машины ТММ
Developed for use with computer-aided design CAD and computer-aided machining CAM , this text is useful for anyone starting work on new software packages for sculptured part surface machining on a multi-axis NC machine. Presents an in—depth analysis of geometry of part surfaces and provides the tools for solving complex engineering problems Geometry of Surfaces: A Practical Guide for Mechanical Engineers is a comprehensive guide to applied geometry of surfaces with focus on practical applications in various areas of mechanical engineering.
A Practical Guide for Mechanical Engineers combines differential geometry and gearing theory and presents new developments in the elementary theory of enveloping surfaces. Written by a leading expert of the field, this book also provides the reader with the tools for solving complex engineering problems in the field of mechanical engineering. Presents an in—depth analysis of geometry of part surfaces Provides tools for solving complex engineering problems in the field of mechanical engineering Combines differential geometry and gearing theory Highlights new developments in the elementary theory of enveloping surfaces Essential reading for researchers and practitioners in mechanical, automotive and aerospace engineering industries; CAD developers; and graduate students in Mechanical Engineering.
This book systematically presents and develops a scientific theory of gearing, specifically for those involved in gear design, analysis, and manufacture. The author begins with a few simple postulates that form the foundation of the theory of gearing. The postulated concepts are limited just to two entities, namely to a rotation vectors of the driving shaft and of the driven shaft, and to b torque on the driving shaft. The rest of the design parameters of an optimal gear pair are derived from the above mentioned input information.
For more than 30 years, the book Practical Gear Design, later re-titled the Handbook of Practical Gear Design, has been the leading engineering guide and reference on the subject. Now available again in this revised edition, the book is a detailed, practical guide and reference to gear technology. It covers the design of all types of gears, from those for small mechanisms to large industrial applications.
The presentation is designed for easy reference for those involved in practical gear design, manufacture, applications, and problem solving. The text is well-illustrated with clear diagrams and photographs. The many tables provide needed reference data in convenient form. Hundreds of photos and schematics clearly illustrate designs and uses; almost tables provide reference data.
This book presents the results of testing and operation experience of Novikov gearing. It gives the grounding, engineering techniques of geometry and strength analysis, definition of the gearing quality and adaptability with account of its manufacture and assembly errors. It outlines the recommendations on the reasonable assignment of basic rack profile parameters, accuracy ratings and design strength safety factors.
Also, ways of load-bearing capacity essential increase are described and several original varieties of Novikov gearing are shown. The examples of engineering and computer-aided calculations of Novikov gearing according to the described techniques are given. This book is dedicated to engineers those who work in the field of gear design, gear production and gear application.
The following is understood by "engineers" in the wide sense of the word, namely those involved in design, those who have to study machining methods, those who have who are responsible for overseeing gear production processes and gear tooling specialists. This book should in part be informative while at the same time they should also form a kind of pocket handbook.