Integrated Kinematic and Dynamic Optimal Design of Flexible Planar Mechanisms

1987 ◽  
Vol 109 (3) ◽  
pp. 338-347 ◽  
Author(s):  
A. J. Kakatsios ◽  
S. J. Tricamo
Keyword(s):  
Cross Sections ◽  
High Speed ◽  
Integrated Approach ◽  
Programming Formulation ◽  
Kinematic Parameters ◽  
Planar Mechanisms ◽  
Disturbing Force ◽  
Design Requirements ◽  
Path Synthesis ◽  
Flexible Mechanisms

The following describes a new integrated approach to the problem of designing high speed mechanisms. Employing a nonlinear programming formulation, it allows both the kinematic parameters and the link cross sections to vary while simultaneously bounding trajectory accuracy and minimizing the disturbing force on the ground. Furthermore, link stresses are bounded to limits imposed by the designer. The technique is capable of taking into account the complex coupling which exists between kinematic and dynamic characteristics in flexible mechanisms to determine linkage parameters which best satisfy a given set of design requirements. A path synthesis problem is used to illustrate the technique.

Integrated Optimal Design of Planar Mechanisms Using Fuzzy Theories

1989 ◽  
Author(s):  
A. K. Dhingra ◽  
S. S. Rao
Keyword(s):  
Nonlinear Programming ◽  
High Speed ◽  
Integrated Approach ◽  
Problem Formulation ◽  
Optimization Techniques ◽  
Motion Path ◽  
Programming Formulation ◽  
Planar Mechanisms ◽  
Dynamic Synthesis ◽  
Motion Characteristics

Abstract A new integrated approach to the design of high speed planar mechanisms is presented. The resulting nonlinear programming formulation combines both the kinematic and dynamic synthesis aspects of mechanism design. The multiobjective optimization techniques presented in this work facilitate the design of a linkage to meet several kinematic and dynamic design criteria. The method can be used for motion, path, and function generation problems. The nonlinear programming formulation also permits the imposition of constraints to eliminate solutions which possess undesirable kinematic and motion characteristics. To model the vague and imprecise information in the problem formulation, the tools of fuzzy set theory have been used. A method of solving the resulting fuzzy multiobjective problem using mathematical programming techniques is presented. The outlined procedure is expected to be useful in situations where doubt arises about the exactness of permissible values, degree of credibility, and correctness of statements and judgements.

An Integrated Kinematic-Kinetostatic Approach to Optimal Design of Planar Mechanisms Using Fuzzy Theories

1991 ◽  
Vol 113 (3) ◽  
pp. 306-311 ◽  
Author(s):  
A. K. Dhingra ◽  
S. S. Rao
Keyword(s):  
Nonlinear Programming ◽  
High Speed ◽  
Integrated Approach ◽  
Problem Formulation ◽  
Optimization Techniques ◽  
Motion Path ◽  
Programming Formulation ◽  
Planar Mechanisms ◽  
Motion Characteristics ◽  
And Function

A new integrated approach to the design of high speed planar mechanisms is presented. The resulting nonlinear programming formulation combines both the kinematic and kinetostatic synthesis aspects of mechanism design. The multiobjective optimization techniques presented in this work facilitate the design of a linkage to meet several kinematic and dynamic design criteria. The method can be used for motion, path, and function generation problems. The nonlinear programming formulation also permits an imposition of constraints to eliminate solutions which possess undesirable kinematic and motion characteristics. To model the vague and imprecise information in the problem formulation, the tools of fuzzy set theory have been used. A novel method of solving the resulting fuzzy multiobjective problem using mathematical programming techniques is presented. The outlined procedure is expected to be useful in situations where doubt arises about the exactness of permissible values, degree of credibility, and correctness of statements and judgements.

scholarly journals An Integrated Approach to Data Path Synthesis for Behavioral-level Power Optimization

VLSI Design ◽  
2000 ◽  
Vol 11 (4) ◽  
pp. 381-396
Author(s):  
Chaeryung Park ◽  
Taewhan Kim ◽  
C. L. Liu
Keyword(s):  
Integer Programming ◽  
Power Consumption ◽  
Efficient Algorithm ◽  
Integrated Approach ◽  
Data Path ◽  
Programming Formulation ◽  
Prior Work ◽  
Design Problems ◽  
Path Synthesis ◽  
Important Design

This paper presents an integrated approach to data path synthesis which solves three important design problems: scheduling, allocation, and hardware partitioning with power minimization as a key design objective. Based on the rules of thumbs introduced in prior work on synthesis for low power we derive an integer programming formulation for solving the problems. We then, based on the formulation, develop an efficient algorithm which performs scheduling, allocation and hardware partitioning simultaneously so that the effects of them on power consumption are exploited more fully and effectively. Our experimentation results show that the algorithm is quite effective, producing designs with significant savings in power consumption.

Articulatory Behavior Pre and Post Full-Mouth Tooth Extraction and Alveoloplasty

1980 ◽  
Vol 23 (3) ◽  
pp. 630-645 ◽  
Author(s):  
Gerald Zimmermann ◽  
J.A. Scott Kelso ◽  
Larry Lander
Keyword(s):  
Control Subject ◽  
High Speed ◽  
Tooth Extraction ◽  
Kinematic Parameters ◽  
Experimental Conditions ◽  
Mean Values ◽  
Articulatory Movements ◽  
The Mean ◽  
Experimental Subjects ◽  
Normal Speech

High speed cinefluorography was used to track articulatory movements preceding and following full-mouth tooth extraction and alveoloplasty in two subjects. Films also were made of a control subject on two separate days. The purpose of the study was to determine the effects of dramatically altering the structural dimensions of the oral cavity on the kinematic parameters of speech. The results showed that the experimental subjects performed differently pre and postoperatively though the changes were in different directions for the two subjects. Differences in both means and variabilities of kinematic parameters were larger between days for the experimental (operated) subjects than for the control subject. The results for the Control subject also showed significant differences in the mean values of kinematic variables between days though these day-to-day differences could not account for the effects found pre- and postoperatively. The results of the kinematic analysis, particularly the finding that transition time was most stable over the experimental conditions for the operated subjects, are used to speculate about the coordination of normal speech.

AN INDEPENDENT ACTIVE BALANCER FOR PLANAR MECHANISMS

2007 ◽  
Vol 31 (2) ◽  
pp. 167-190 ◽  
Author(s):  
Zhang Ying ◽  
Yao Yan-An ◽  
Cha Jian-Zhong
Keyword(s):  
Working Conditions ◽  
Design Method ◽  
Design Procedure ◽  
Vibration Absorber ◽  
Planar Mechanisms ◽  
Dynamic Balancing ◽  
Joint Coupling ◽  
Design Requirements ◽  
Novel Concept ◽  
Two Degree Of Freedom

This paper proposed a novel concept of active balancer for dynamic balancing of planar mechanisms. Somewhat similar to a vibration absorber, the active balancer is designed as an independent device, which is placed outside of the mechanism to be balanced and can be installed easily. It consists of a two degree-of-freedom (DOF) linkage with two input shafts, one of which is connected to the output shaft of the mechanism to be balanced by a joint coupling, and the other one is driven by a controllable motor. Flexible dynamic balancing adapted to different working conditions can be achieved by varying speed trajectories of the control motor actively. A design method is developed for selecting suitable speed trajectories and link parameters of the two DOF linkage of the balancer to meet various design requirements and constraints. Numerical examples are given to demonstrate the design procedure and to verify the feasibility of the proposed concept.

Acoustic resonances and trapped modes in pipes and tunnels

2008 ◽  
Vol 605 ◽  
pp. 401-428 ◽  
Author(s):  
STEFAN HEIN ◽  
WERNER KOCH
Keyword(s):  
Cross Sections ◽  
High Speed ◽  
Hard Spheres ◽  
Cutoff Frequency ◽  
Three Dimensional ◽  
Absorbing Boundary Conditions ◽  
Trapped Modes ◽  
Absorbing Boundary ◽  
Complex Scaling Method ◽  
Acoustic Resonances

Acoustic resonances of simple three-dimensional finite-length structures in an infinitely long cylindrical pipe are investigated numerically by solving an eigenvalue problem. To avoid unphysical reflections at the finite grid boundaries placed in the uniform cross-sections of the pipe, perfectly matched layer absorbing boundary conditions are applied in the form of the complex scaling method of atomic and molecular physics. Examples of the structures investigated are sound-hard spheres, cylinders, cavities and closed side branches. Several truly trapped modes with zero radiation loss are identified for frequencies below the first cutoff frequency of the pipe. Such trapped modes can be excited aerodynamically by coherent vortices if the frequency of the shed vortices is close to a resonant frequency. Furthermore, numerical evidence is presented for the existence of isolated embedded trapped modes for annular cavities above the first cutoff frequency and for closed side branches below the first cutoff frequency. As applications of engineering interest, the acoustic resonances are computed for a ball-type valve and around a simple model of a high-speed train in an infinitely long tunnel.

scholarly journals Is ink heating a relevant concern in the High Speed Sintering process?

2021 ◽  
Author(s):  
Rhys J. Williams ◽  
Patrick J. Smith ◽  
Candice Majewski
Keyword(s):  
Cross Sections ◽  
Inkjet Printing ◽  
High Speed ◽  
Sintering Process ◽  
Significant Drop ◽  
Powder Bed ◽  
Consistent Manner ◽  
Fluid Properties ◽  
Different Temperatures ◽  
Accuracy And Repeatability

AbstractHigh Speed Sintering (HSS) is a novel polymer additive manufacturing process which utilises inkjet printing of an infrared-absorbing pigment onto a heated polymer powder bed to create 2D cross-sections which can be selectively sintered using an infrared lamp. Understanding and improving the accuracy and repeatability of part manufacture by HSS are important, ongoing areas of research. In particular, the role of the ink is poorly understood; the inks typically used in HSS have not been optimised for it, and it is unknown whether they perform in a consistent manner in the process. Notably, the ambient temperature inside a HSS machine increases as a side effect of the sintering process, and the unintentional heating to which the ink is exposed is expected to cause changes in its fluid properties. However, neither the extent of ink heating during the HSS process nor the subsequent changes in its fluid properties have ever been investigated. Such investigation is important, since significant changes in ink properties at different temperatures would be expected to lead to inconsistent printing and subsequently variations in part accuracy and even the degree of sintering during a single build. For the first time, we have quantified the ink temperature rise caused by unintentional, ambient heating during the HSS process, and subsequently measured several of the ink’s fluid properties across the ink temperature range which is expected to be encountered in normal machine operation (25 to 45 ∘C). We observed only small changes in the ink’s density and surface tension due to this heating, but a significant drop (36%) in its viscosity was seen. By inspection of the ink’s Z number throughout printing, it is concluded that these changes would not be expected to change the manner in which droplets are delivered to the powder bed surface. In contrast, the viscosity decrease during printing is such that it is expected that the printed droplet sizes do change in a single build, which may indeed be a cause for concern with regard to the accuracy and repeatability of the inkjet printing used in HSS, and subsequently to the properties of the polymer parts obtained from the process.

Adequate Strength for Small High-Speed Vessels

1968 ◽  
Vol 5 (01) ◽  
pp. 63-71
Author(s):  
Philip J. Danahy
Keyword(s):  
Stress Analysis ◽  
High Speed ◽  
Structural Strength ◽  
Integrated Approach ◽  
Suggested Method ◽  
Impact Loads ◽  
Analysis Method ◽  
Safety Factors ◽  
Recreational Vessels

The paper presents a method for the determination of the critical minimum scantlings for small high-speed vessels. Particular attention is given to the shell plating strength for hydrodynamic impact loads. The suggested method uses an integrated approach involving assumed loads, suggested safety factors, and preferred stress-analysis method. The stress analysis uses plastic theory based partly on the works of J. Clarkson and Thein Wah. Included in the paper is a comparison of the relative structural strength of several commercial, military, and experimental hydrofoil vessels along with a few planing boats and a seaplane hull. This shows the variation of existing vessel structures and compares them to the results obtained by the suggested method. Most commercial, military, and recreational vessels exceed the minimum scantlings of the suggested method. The most significant deviation is the hull of the seaplane:

scholarly journals On the Creation of a High-Speed Transport Highway in St. Petersburg

2019 ◽  
Vol 5 (4) ◽  
pp. 73-95
Author(s):  
Nikolai A. Senkin ◽  
Aleksandr S. Filimonov ◽  
Kirill E. Kharitonov ◽  
Vitaliy V. Yakovlev ◽  
Elizaveta O. Bondareva ◽  
...  
Keyword(s):  
Transport System ◽  
Cross Sections ◽  
High Speed ◽  
Tube Steel ◽  
Leningrad Region ◽  
Limit States ◽  
Passenger Traffic ◽  
Rod System ◽  
The Creation ◽  
Selection Of

As part of student research at the St. Petersburg University of architecture and construction, alternative proposals are being developed for the creation of a circumferential high-speed highway with a total length of 147.2 km. Тhe scheme is proposed in the form of a polygon with HUB in the nodes and consists of three main parts: 1 above-ground (62.6 km), 2 above-water (29.6 km) and 3 surface-underground (55.0 km). The main tracks are located in a four-tube steel beam, each tube of which is organized by the technology of vacuum tube transport with a pressure of 10% of the normal for high-speed passenger trains on a magnetic levitation cushion using a linear traction motor (Maglev system). The rail base of the 1520 mm gauge is located along the entire length of the track, both in parking lots, acceleration and braking zones, and on the main high-speed sections for movement with a maximum speed of 500 km per hour. The main direction of research was the development of load-bearing structures that provide the necessary functionality, reliability and safety of structures. In order to reduce the noise impact on the metropolis, overcome numerous artificial and natural obstacles, improve anti-terrorist protection, the main level of the rail track for the above-ground and above-water structures was adopted at +88.00 in the Baltic elevation system. Calculations of variants with determination of internal forces in elements and movements of nodes with use of the program complex SCAD Office 21.1are executed, when accounting for the full range of loads taking into account dynamic effects and non-linearity. The selection of cross-sections of elements according to the method of limit states according to the current norms is carried out. The advantage of the arch-cable-stayed variant with a span of 360 m in strength, stability, stiffness and vertical size (height of supports) is shown. The continuation of research and design work on this topic should lead to the emergence of a district high-speed transport system at the borders of communication between St. Petersburg and the Leningrad region with passenger traffic, quite comparable to the metro line. Aim: To develop a district high-speed transport system at the borders of St. Petersburg and Leningrad region with passenger traffic comparable to the metro line. Materials and Methods: Using the software package "SCAD Office 21.1", the trestle structures are calculated for the combination of operating loads, forces and influences, including the consideration of dynamic aspects and nonlinearity, as well as the selection of cross-sections of elements by the method of limit states. To determine the optimal trestle structures of high-speed highways, namely high-rise and long-length metal structures supporting the overpass beam, calculations with the selection of cross sections of four variants of cable-stayed systems (arch-cable-stayed; cable-stayed rod with inclined cables and steel lattice pylons; the same, steel pipe-concrete pylons; cable-stayed rod system with suspensions according to the patent US5950543 (A). Results: the results of the trial design adopted arch-cable option with a span of 360 m according to the criterion of metal consumption, the consumption of steel amounted to 20.9 tons per 1 m length of highway. Conclusion: the estimated volume of passenger traffic per day for the four-track high-speed line will be 280 thousand passengers, and 102 million passengers per year, which is quite comparable to this figure for the metro line.

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