Minimum Weight Design of a Car Trunk Deck-Lid Subject to Overall Stiffness Constraints

1982 ◽  
Vol 104 (4) ◽  
pp. 831-836 ◽  
Author(s):  
H. A. Du ◽  
S. C. Tang
Keyword(s):  
Minimum Weight ◽  
Optimization Technique ◽  
Design Procedure ◽  
Optimization Techniques ◽  
Structural Components ◽  
Minimum Weight Design ◽  
Design Constraints ◽  
Design Variables ◽  
Practical Design ◽  
Weight Design

A design procedure for a car trunk deck-lid using an approximate optimization technique is presented. Selecting the deck-lid gages and deck-lid inner panel configuration as design variables and overall stiffnesses as constraints, a possible weight reduction of 20 percent is demonstrated, compared with the base production deck-lid design. Although other practical design constraints might not allow one to achieve this goal, the potential value of optimization techniques is clearly demonstrated by this study. It is concluded that it could be useful to develop and apply such a procedure to components such as hoods, deck-lids, doors, and fenders, which are isolatable as structural components.

Minimum Weight Design Problems of Fiber-Reinforced Beam Subjected to Uniform Bending

1985 ◽  
Vol 107 (1) ◽  
pp. 88-93 ◽  
Author(s):  
Juhachi Oda
Keyword(s):  
Minimum Weight ◽  
Bending Moment ◽  
Material Strength ◽  
Sequential Linear Programming ◽  
Volume Percent ◽  
Fiber Volume ◽  
Minimum Weight Design ◽  
Design Problems ◽  
Design Variables ◽  
Weight Design

Problems considered here are that of minimizing the weight of beams, which are subjected to a uniform bending moment and reinforced by the fibers distributed in the direction of beam axis. The beam is simplified as a multilaminate structure, of which the fiber volume percent Vfi of each lamina is considered as the design variables. To formulate this design problem the bending theory of multilaminate beam and the law of mixture for the composite material strength are applied. Furthermore, the sequential linear programming and the sequential unconstrianed minimization techniques are used to obtain the design solutions numerically.

Minimum-Weight Design of Stiffened Cylinders Under Hydrostatic Pressure

1977 ◽  
Vol 21 (04) ◽  
pp. 217-224
Author(s):  
G. J. Simitses ◽  
M. Aswani
Keyword(s):  
Hydrostatic Pressure ◽  
Objective Function ◽  
Failure Modes ◽  
Minimum Weight ◽  
Minimum Weight Design ◽  
Design Charts ◽  
Design Variables ◽  
Weight Penalty ◽  
Weight Design ◽  
Two Stages

A methodology is developed by which one may design a stiffened cylinder of specified material, radius and length such that it can carry safely a given hydrostatic pressure with minimum weight. The solution is accomplished in two stages. First, design charts based on a simplified formulation of the objective function are obtained. Second, these design charts are used to evaluate the design variables. Such an approach enables the designer to introduce needed changes or avoid interaction of failure modes by paying the least weight penalty. Design examples are presented and the results are compared with those obtained by other investigators.

scholarly journals Design Optimization of Composite Laminated Tube Based on Improved Niching Evolutionary Algorithm

2017 ◽  
Vol 2017 ◽  
pp. 1-11 ◽  
Author(s):  
Sen Ma ◽  
Qilin Zhao ◽  
Darong Pan
Keyword(s):  
Optimal Design ◽  
Evolutionary Algorithms ◽  
Objective Function ◽  
Evolutionary Algorithm ◽  
Minimum Weight ◽  
Local Optimum ◽  
Optimal Result ◽  
Minimum Weight Design ◽  
Design Variables ◽  
Weight Design

A minimum weight design is developed for a composite laminated tube considering the number of plies as one of the design variables. The objective function is found to be complex, and more than one optimal design point may exist with different numbers of plies. Existing methods based on evolutionary algorithms tend to become trapped around a local optimum and can find no more than one optimal result per calculation. Aiming at the characteristics of the objective function, an improved evolutionary algorithm (INDE for short) is established based on niching technology. The formula for calculating the distance between individuals in the niching technology is improved to satisfy the minimum weight design for the composite laminated tube. As a result, the improved niching evolutionary algorithm offers better global search ability and can find more than one optimal result per calculation for different numbers of plies.

Minimum Weight Design of Laminated Composite Plates for Postbuckling Performance

1991 ◽  
Vol 44 (11S) ◽  
pp. S219-S231 ◽  
Author(s):  
Dong Ku Shin ◽  
Zafer Gu¨rdal ◽  
O. Hayden Griffin
Keyword(s):  
Minimum Weight ◽  
Optimization Technique ◽  
Composite Plates ◽  
Laminated Plates ◽  
Orthotropic Plates ◽  
Minimum Weight Design ◽  
Individual Layer ◽  
Aspect Ratios ◽  
Weight Design ◽  
Discrete Values

Minimum-weight design of simply-supported, symmetrically laminated, thin, rectangular, specially orthotropic laminated plates for buckling and postbuckling strength is investigated. The postbuckling analysis is based on an Marguerre-type energy method extended to generally orthotropic plates with a special consideration of the mode change in the postbuckling load regime. The failure load of laminates is calculated by the maximum strain failure criterion based on the in-plane strains. Design variables are individual layer thicknesses with specified fiber orientations and assumed to take only discrete values corresponding to multiples of the lamina thickness. The optimization with discrete valued design is achieved by introducing additional penalty terms, in the form of a sine function, to the regular pseudo-objective function of sequential unconstrained minimization technique (SUMT). The proposed optimization technique is applied to the design of rectangular laminates made up of 0, ± 45, 90 degree laminae with various aspect ratios loaded by axial compressive loads.

scholarly journals Flutter Characteristic Study of Composite Sandwich Panel with Functionally Graded Foam Core

2016 ◽  
Vol 2016 ◽  
pp. 1-9 ◽  
Author(s):  
Peng Jin ◽  
Xiaoping Zhong
Keyword(s):  
Sandwich Panel ◽  
Minimum Weight ◽  
Functionally Graded ◽  
Foam Core ◽  
Minimum Weight Design ◽  
Direction Parallel ◽  
Composite Sandwich ◽  
Flutter Speed ◽  
Design Variables ◽  
Weight Design

This paper attempts to investigate the flutter characteristic of sandwich panel composed of laminated facesheets and a functionally graded foam core. The macroscopic properties of the foam core change continuously along this direction parallel to the facesheet lamina. The model used in the study is a simple sandwich panel-wing clamped at the root, with three simple types of grading strategies for FGM core: (1) linear grading strategy in the chord-wise direction, (2) linear grading strategy in the span-wise direction, and (3) bilinear grading of properties of foam core across the panel. The results show that use of FGM core has the potential to increase the flutter speed of the sandwich panel. Finally, a minimum weight design of composite sandwich panel with lamination parameters of facesheet and density distribution of foam core as design variables is conducted using particle swarm optimization (PSO).

Minimum Weight Design of a Rotor Bearing System With Multiple Frequency Constraints

1988 ◽  
Vol 110 (4) ◽  
pp. 592-599 ◽  
Author(s):  
Ting Nung Shiau ◽  
Jon Li Hwang
Keyword(s):  
Minimum Weight ◽  
Optimization Techniques ◽  
Multiple Frequency ◽  
Minimum Weight Design ◽  
Feasible Directions ◽  
Frequency Constraints ◽  
Design Algorithm ◽  
Rotor Bearing ◽  
Weight Design ◽  
Bearing System

The objective of the present study is to develop an efficient design algorithm for minimum weight design of a rotor bearing system under the requirements of operational speed range, i.e., multiple frequency constraints, to increase the performance of an existent rotor system. The system is modeled as an assemblage of rigid disks, shaft elements with distributed mass and stiffness, and discrete bearings. The system design variables are the inner radius of shaft elements and the stiffnesses of bearings. The optimization techniques employed to compare the results are method of exterior penalty function, method of feasible directions, and method of modified feasible directions. The parameter sensitivity analysis of the system is also presented. Three examples are used to demonstrate the merits of the design algorithm. The results indicate that the weight of the rotor bearing system can be significantly reduced at the optimum stage.

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