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.

Note on the Minimum-Weight Design of Thin-Walled Cells in Combined Bending and Torsion

1956 ◽  
Vol 60 (541) ◽  
pp. 65-66 ◽  
Author(s):  
V. Cadambe ◽  
S. Krishnan
Keyword(s):  
Minimum Weight ◽  
Bending Moment ◽  
Rational Approach ◽  
Pure Torsion ◽  
Minimum Weight Design ◽  
Weight Design ◽  
Thin Walled

In a recent paper the authors suggested that the minimum weight design of thin-walled cells in combined bending and torsion could be tackled by using the well-known concept of equivalent bending moment and torque. It is now felt that a more rational approach would be to base the analysis on the buckling behaviour of the walls of the cell under combined compression and shear and choose the dimensions such that the cell will just resist buckling. The second criterion for design is taken as a limit on the twist as adapted in the case of pure torsion. Two types of sections, rectangular and circular, are discussed in this note.

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 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.

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).

Mathematical Programming Procedures for Mixed Discrete-Continuous Design Problems

1974 ◽  
Vol 96 (1) ◽  
pp. 201-209 ◽  
Author(s):  
M. Pappas ◽  
A. Allentuch
Keyword(s):  
Mathematical Programming ◽  
Minimum Weight ◽  
Nonlinear Problems ◽  
Continuous Variables ◽  
Minimum Weight Design ◽  
Design Problems ◽  
Mixed Variables ◽  
Discrete Search ◽  
Weight Design ◽  
Stiffened Cylindrical Shells

Two mathematical programming procedures for treating nonlinear problems involving mixed variables are presented. One involves a relatively simple concept. First an optimum is located treating all variables as continuous. Adjacent discrete points are then evaluated in order of increasing distance from the all-continuous optimum, each evaluation requiring an optimization of the continuous variables, if any, until a satisfactory design is found. The other method utilizes an optimal discrete search to locate the optimum. These procedures are applied to the minimum weight design of stiffened, cylindrical shells where they prove to be effective.

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