The Optimum Design of Mechanical Systems With Competing Design Objectives

1974 ◽  
Vol 96 (1) ◽  
pp. 171-178 ◽  
Author(s):  
D. L. Bartel ◽  
R. W. Marks
Keyword(s):  
Optimum Design ◽  
Mechanical Systems ◽  
Journal Bearings ◽  
Design Problems ◽  
Trade Off ◽  
General Method

A general method is developed for analyzing optimum design problems with multiple, competing objective junctions. Methods are presented for generating trade-off curves for problems with competing objectives. The usefulness of these methods is demonstrated by applying them to the optimum design of hydrodynamic journal bearings.

scholarly journals Mobility Method Applied to Calculate the Lubrication Properties of Bearing under Dynamic Loads

2013 ◽  
Vol 2013 ◽  
pp. 1-5 ◽  
Author(s):  
Tao He ◽  
Xiqun Lu ◽  
Jingzhi Zhu
Keyword(s):  
Dynamic Analysis ◽  
Mechanical Systems ◽  
Journal Bearings ◽  
Numerical Results ◽  
Dynamic Loads ◽  
Analysis Program ◽  
Computational Program ◽  
Dynamically Loaded ◽  
Mobility Method ◽  
Lubrication Properties

The analytical mobility method for dynamically loaded journal bearings was presented, with the intent to include it in a general computational program, such as the dynamic analysis program, that has been developed for the dynamic analysis of general mechanical systems. An illustrative example and numerical results were presented, with the efficiency of the method being discussed in the process of their presentation.

A trade-off function to tackle robust design problems in engineering

2013 ◽  
Vol 24 (1) ◽  
pp. 64-81 ◽  
Author(s):  
Thomas Quirante ◽  
Patrick Sebastian ◽  
Yann Ledoux
Keyword(s):  
Robust Design ◽  
Design Problems ◽  
Trade Off

Possibility-Based Design Optimization Method for Design Problems With Both Statistical and Fuzzy Input Data

2005 ◽  
Vol 128 (4) ◽  
pp. 928-935 ◽  
Author(s):  
Liu Du ◽  
K. K. Choi ◽  
Byeng D. Youn ◽  
David Gorsich
Keyword(s):  
Design Optimization ◽  
Optimum Design ◽  
Membership Function ◽  
Input Data ◽  
Performance Measure ◽  
Sufficient Data ◽  
Design Problems ◽  
Fuzzy Variables ◽  
Fuzzy Input ◽  
The Membership Function

The reliability based design optimization (RBDO) method is prevailing in stochastic structural design optimization by assuming the amount of input data is sufficient enough to create accurate input statistical distribution. If the sufficient input data cannot be generated due to limitations in technical and/or facility resources, the possibility-based design optimization (PBDO) method can be used to obtain reliable designs by utilizing membership functions for epistemic uncertainties. For RBDO, the performance measure approach (PMA) is well established and accepted by many investigators. It is found that the same PMA is a very much desirable approach also for the PBDO problems. In many industry design problems, we have to deal with uncertainties with sufficient data and uncertainties with insufficient data simultaneously. For these design problems, it is not desirable to use RBDO since it could lead to an unreliable optimum design. This paper proposes to use PBDO for design optimization for such problems. In order to treat uncertainties as fuzzy variables, several methods for membership function generation are proposed. As less detailed information is available for the input data, the membership function that provides more conservative optimum design should be selected. For uncertainties with sufficient data, the membership function that yields the least conservative optimum design is proposed by using the possibility-probability consistency theory and the least conservative condition. The proposed approach for design problems with mixed type input uncertainties is applied to some example problems to demonstrate feasibility of the approach. It is shown that the proposed approach provides conservative optimum design.

Dynamics of a Multibody Mechanical System With Lubricated Long Journal Bearings

2004 ◽  
Vol 127 (3) ◽  
pp. 493-498 ◽  
Author(s):  
B. J. Alshaer ◽  
H. Nagarajan ◽  
H. K. Beheshti ◽  
H. M. Lankarani ◽  
S. Shivaswamy
Keyword(s):  
Dynamic Response ◽  
Mechanical System ◽  
Journal Bearing ◽  
Initial Conditions ◽  
Equations Of Motion ◽  
Mechanical Systems ◽  
Journal Bearings ◽  
Connecting Rod ◽  
Revolute Joint ◽  
Order Of Magnitude

Clearances exist in different kinds of joints in multibody mechanical systems, which could drastically affect the dynamic behavior of the system. If the joint is dry with no lubricant, impact occurs, resulting in wear and tear of the joint. In practical engineering design of machines, joints are usually designed to operate with some lubricant. Lubricated journal bearings are designed so that even when the maximum load is applied, the joint surfaces do not come into contact with each other. In this paper, a general methodology for modeling lubricated long journal bearings in multibody mechanical systems is presented. This modeling utilizes a method of solving for the forces produced by the lubricant in a dynamically loaded long journal bearing. A perfect revolute joint in a multibody mechanical system imposes kinematic constraints, while a lubricated journal bearing joint imposes force constraints. As an application, the dynamic response of a slider-crank mechanism including a lubricated journal bearing joint between the connecting rod and the slider is considered and analyzed. The dynamic response is obtained by numerically solving the constraint equations and the forces produced by the lubricant simultaneously with the differential equations of motion and a set of initial conditions numerically. The results are compared with the previous studies performed on the same mechanism as well a dry clearance joint. It is shown that in a multibody mechanical system, the journal bearing lubricant introduces damping and stiffness to the system. The earlier studies predict that the order of magnitude of the reaction moment is twice that of a perfect revolute joint. The proposed model predicts that the reaction moment is within the same order of magnitude of the perfect joint simulation case.

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