Heuristic Optimization in the Balancing of High Speed Rotors

1984 ◽  
Vol 106 (2) ◽  
pp. 163-169
Author(s):  
J. L. Yang ◽  
F. H. Chu ◽  
Ting W. Lee
Keyword(s):  
High Speed ◽  
Optimization Technique ◽  
Heuristic Optimization ◽  
Dynamic Balancing ◽  
Design Constraints ◽  
New Approach ◽  
Flexible Rotors

This paper presents a new approach to the dynamic balancing of flexible rotors. The unbalance of a rotor is treated as a combination of a number of discrete unbalancing components, which are identified and subsequently removed using an effective heuristic optimization technique. The method allows the treatment of nonlinear rotor response and design constraints. A specific example is used to illustrate the approach and the results are compared with the ones obtained using another optimum balancing technique.

Optimum Balancing of Combined Shaking Force, Shaking Moment, and Torque Fluctuations in High-Speed Linkages

1984 ◽  
Vol 106 (2) ◽  
pp. 242-251 ◽  
Author(s):  
T. W. Lee ◽  
C. Cheng
Keyword(s):  
High Speed ◽  
Optimization Technique ◽  
Integrated Approach ◽  
Optimization Techniques ◽  
Theoretical Development ◽  
Design Stage ◽  
Heuristic Optimization ◽  
Analytical Mechanics ◽  
Trade Offs ◽  
Shaking Moment

This paper presents an analytical and computer-aided procedure on the balancing of high-speed linkages. The method allows for the trade-offs necessary to achieve optimum dynamic response of the linkage in the design stage. These trade-offs involve a balance among the shaking force, the shaking moment, bearing reactions, and input-torque fluctuations by mass distribution of the links or counterweighting the linkage. Analytical mechanics and heuristic optimization techniques have been demonstrated to be useful tools in developing such a trade-off. The first part of this paper concerns the development of an optimality criterion in which an integrated approach is presented using both the Lagrangian and the Newtonian formulations, and consequently, a higher computational efficiency is achieved. Based on this theoretical development, the remainder of the paper focuses on the formulation of an optimization problem for linkage balancing and the solution of the problem by the Heuristic Optimization Technique of Lee and Freudenstein. The theory and computation are illustrated by numerical examples in the case of four-bar linkages.

Yaw Galloping of a TLWP Platform Under High Speed Currents by Analytical Methods and its Comparison With Experimental Results

2017 ◽  
Author(s):  
Francisco Lamas ◽  
Miguel A. M. Ramirez ◽  
Antonio Carlos Fernandes
Keyword(s):  
High Speed ◽  
Production Systems ◽  
Experimental Tests ◽  
Experimental Results ◽  
Analytical Methodology ◽  
New Approach ◽  
Laboratory Facilities ◽  
Polynomial Curve ◽  
Computational Fluid Dynamics Cfd ◽  
Cfd Analyses

Flow Induced Motions are always an important subject during both design and operational phases of an offshore platform life. These motions could significantly affect the performance of the platform, including its mooring and oil production systems. These kind of analyses are performed using basically two different approaches: experimental tests with reduced models and, more recently, with Computational Fluid Dynamics (CFD) dynamic analysis. The main objective of this work is to present a new approach, based on an analytical methodology using static CFD analyses to estimate the response on yaw motions of a Tension Leg Wellhead Platform on one of the several types of motions that can be classified as flow-induced motions, known as galloping. The first step is to review the equations that govern the yaw motions of an ocean platform when subjected to currents from different angles of attack. The yaw moment coefficients will be obtained using CFD steady-state analysis, on which the yaw moments will be calculated for several angles of attack, placed around the central angle where the analysis is being carried out. Having the force coefficients plotted against the angle values, we can adjust a polynomial curve around each analysis point in order to evaluate the amplitude of the yaw motion using a limit cycle approach. Other properties of the system which are flow-dependent, such as damping and added mass, will also be estimated using CFD. The last part of this work consists in comparing the analytical results with experimental results obtained at the LOC/COPPE-UFRJ laboratory facilities.

scholarly journals Buyer Inspired Meta-Heuristic Optimization Algorithm

2020 ◽  
Vol 10 (1) ◽  
pp. 194-219 ◽  
Author(s):  
Sanjoy Debnath ◽  
Wasim Arif ◽  
Srimanta Baishya
Keyword(s):  
Optimization Algorithm ◽  
Optimization Technique ◽  
Statistical Test ◽  
Heuristic Optimization ◽  
Product Choice ◽  
Exploration And Exploitation ◽  
The Social ◽  
Engineering Problems ◽  
The Mean

AbstractNature inspired swarm based meta-heuristic optimization technique is getting considerable attention and established to be very competitive with evolution based and physical based algorithms. This paper proposes a novel Buyer Inspired Meta-heuristic optimization Algorithm (BIMA) inspired form the social behaviour of human being in searching and bargaining for products. In BIMA, exploration and exploitation are achieved through shop to shop hoping and bargaining for products to be purchased based on cost, quality of the product, choice and distance to the shop. Comprehensive simulations are performed on 23 standard mathematical and CEC2017 benchmark functions and 3 engineering problems. An exhaustive comparative analysis with other algorithms is done by performing 30 independent runs and comparing the mean, standard deviation as well as by performing statistical test. The results showed significant improvement in terms of optimum value, convergence speed, and is also statistically more significant in comparison to most of the reported popular algorithms.

scholarly journals A New Approach to Assess the Quality of Small High-Speed Centrifugal Fans Using Noise Measurement

1999 ◽  
Vol 5 (2) ◽  
pp. 147-153 ◽  
Author(s):  
Dingjun Cui ◽  
Ian A. Craighead
Keyword(s):  
Signal Processing ◽  
Quality Assessment ◽  
Condition Monitoring ◽  
High Speed ◽  
Noise Levels ◽  
New Approach ◽  
Commercial Market ◽  
Centrifugal Fans ◽  
Special Approach

The requirements for a special approach for the quality assessment of small high-speed centrifugal fans are outlined and a new parameter designating the noise levels from the product in comprehensive form will be discussed and described as a criterion for such quality assessment.By applying techniques of signal processing and condition monitoring, the sources of the vibration and noise in different sections of the product can be identified, then the noise from each source from different components can be determined. Using this criterion, more aspects of the quality of the products can be assessed and suggestions to improve the quality of the products can be made. Finally, the assessment of a number ofvacuum cleaner motor/fan units available in the commercial market will be presented and compared with conventional specifications. It will be shown that the new parameter provides a more useful indication of appliance quality.

scholarly journals Quasi-two-dimensional approximation for numerical simulation of flows in engine ducts

2019 ◽  
Author(s):  
V. Vlasenko ◽  
A. Shiryaeva
Keyword(s):  
High Speed ◽  
Fuel Injection ◽  
Three Dimensional ◽  
Preliminary Design ◽  
Two Dimensional ◽  
Combustion Chambers ◽  
New Approach ◽  
One Dimensional ◽  
Dimensional Approximation ◽  
3D Flows

New quasi-two-dimensional (2.5D) approach to description of three-dimensional (3D) flows in ducts is proposed. It generalizes quasi-one-dimensional (quasi-1D, 1.5D) theories. Calculations are performed in the (x; y) plane, but variable width of duct in the z direction is taken into account. Derivation of 2.5D approximation equations is given. Tests for verification of 2.5D calculations are proposed. Parametrical 2.5D calculations of flow with hydrogen combustion in an elliptical combustor of a high-speed aircraft, investigated within HEXAFLY-INT international project, are described. Optimal scheme of fuel injection is found and explained. For one regime, 2.5D and 3D calculations are compared. The new approach is recommended for use during preliminary design of combustion chambers.

scholarly journals Modal Kinematic Analysis of a Parallel Kinematic Robot with Low-Stiffness Transmissions

Robotics ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 132
Author(s):  
Paolo Righettini ◽  
Roberto Strada ◽  
Filippo Cortinovis
Keyword(s):  
High Speed ◽  
Parallel Robots ◽  
Maximum Speed ◽  
Kinematic Structure ◽  
End Effector ◽  
New Approach ◽  
Working Space ◽  
Modes Of Vibration ◽  
Parallel Kinematic ◽  
Actuated Joints

Several industrial robotic applications that require high speed or high stiffness-to-inertia ratios use parallel kinematic robots. In the cases where the critical point of the application is the speed, the compliance of the main mechanical transmissions placed between the actuators and the parallel kinematic structure can be significantly higher than that of the parallel kinematic structure itself. This paper deals with this kind of system, where the overall performance depends on the maximum speed and on the dynamic behavior. Our research proposes a new approach for the investigation of the modes of vibration of the end-effector placed on the robot structure for a system where the transmission’s compliance is not negligible in relation to the flexibility of the parallel kinematic structure. The approach considers the kinematic and dynamic coupling due to the parallel kinematic structure, the system’s mass distribution and the transmission’s stiffness. In the literature, several papers deal with the dynamic vibration analysis of parallel robots. Some of these also consider the transmissions between the motors and the actuated joints. However, these works mainly deal with the modal analysis of the robot’s mechanical structure or the displacement analysis of the transmission’s effects on the positioning error of the end-effector. The discussion of the proposed approach takes into consideration a linear delta robot. The results show that the system’s natural frequencies and the directions of the end-effector’s modal displacements strongly depend on its position in the working space.

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