scholarly journals An approach for the design of multi-material mechanical components

2018 ◽  
Vol 233 (3) ◽  
pp. 960-974 ◽  
Author(s):  
Konstantinos Anyfantis ◽  
Panagiotis Stavropoulos ◽  
Panagis Foteinopoulos ◽  
George Chryssolouris
Keyword(s):  
Structural Design ◽  
Strain Energy ◽  
Computational Procedure ◽  
Partial Replacement ◽  
Objective Functions ◽  
Reinforced Composite ◽  
Design Variables ◽  
Design Requirements ◽  
Strain Energy Minimization ◽  
Good Set

A computational procedure for the calculation of the material parameters involved in the structural design of multi-material components is presented. The developed scheme can be used in the design process for the full or partial replacement of a metallic part with a metal/fiber–reinforced composite bi-material, aiming at weight savings. Finite element simulations are incorporated into an algorithm that rapidly reduces the design space until a good set of design variables has been reached. The process is controlled by two objective functions (mass and strain energy minimization) and is subjected to several constraints according to the component’s design requirements. Three examples have been adopted to demonstrate the effectiveness of the approach. The results show that the upper limit for weight reduction is constrained by the yield strength of the metal component and therefore its corresponding thickness. Based on the design configuration, weight savings up to 25% could be reached.

Multi-Factor Optimisation of Large Reflector Antenna Structures

1996 ◽  
Vol 11 (3) ◽  
pp. 307-320 ◽  
Author(s):  
J.S. Liu ◽  
L Hollaway
Keyword(s):  
Mathematical Model ◽  
Evaluation Criteria ◽  
Reflector Antenna ◽  
Objective Functions ◽  
Antenna Structure ◽  
Working Environments ◽  
Design Variables ◽  
Design Requirements ◽  
Optimisation Procedure ◽  
Antenna Reflector

A novel multi-parameter overall situation optimisation method has been developed for use on antenna reflector structures. Various structural performances arc included as objective functions. The design variables involve geometric and size variables of structures. Various working environments and loading cases which affect antenna performances could be combined in the optimisation mathematical model. An important aspect to the work is the establishment of evaluation criteria to optimise the design of a system. Such an optimisation procedure would satisfy extremely high design requirements. An 8m antenna structure is significantly optimised and the results are given.

scholarly journals Applying the genetic algorithm and the consequential convex approximation programming for composite structure optimization

2004 ◽  
Vol 26 (4) ◽  
pp. 247-256
Author(s):  
Nguyen Thoi Trung ◽  
Ngo Thanh Phong
Keyword(s):  
Genetic Algorithm ◽  
Strain Energy ◽  
Elastic Fiber ◽  
Structure Optimization ◽  
Optimization Techniques ◽  
Convex Approximation ◽  
Fiber Reinforced Composite ◽  
Linear Elastic ◽  
Reinforced Composite ◽  
Design Variables

This paper applies the genetic algorithm and consequential convex approximation programming to deal with problems of minimizing the strain energy of a linear elastic fiber reinforced composite laminate in a state of plane stress. The directions of fibers are used as design variables. From the numerical results, an evaluation of two optimization techniques is performed.

Multi-Objective Optimization of Piezoelectric Microactuator Using Genetic Algorithms

2008 ◽  
Author(s):  
H. Esteki ◽  
A. Hasannia
Keyword(s):  
Genetic Algorithms ◽  
Strain Energy ◽  
Compliant Mechanism ◽  
Objective Functions ◽  
Multi Objective Optimization ◽  
Cross Sectional ◽  
Flexure Hinges ◽  
Design Variables ◽  
Cross Sectional Size ◽  
Real Coded Genetic Algorithms

In flex-tensional piezoactuators, due to the low displacement of piezostacks, a compliant mechanism is used to amplify displacement of piezostack. In this paper, optimization of a compliant mechanism with corner-filleted flexure hinges is carried out using real-coded genetic algorithms (GAs) to avoid trapping in local optimums. The objective functions are displacement amplification and stiffness of mechanism and design variables are cross-sectional size and material used. The constraints which are applied on mechanism are based on piezostack dimensions and manufacturing limits. Displacement amplification and stiffness are calculated using strain energy and Castigliano’s displacement theorem.

Multi-Objective Design Problem of Tire Wear and Visualization of Its Pareto Solutions2

2006 ◽  
Vol 34 (3) ◽  
pp. 170-194 ◽  
Author(s):  
M. Koishi ◽  
Z. Shida
Keyword(s):  
Inverse Problems ◽  
Conceptual Design ◽  
Dimensional Space ◽  
Design Stage ◽  
Objective Functions ◽  
Pareto Solutions ◽  
Design Problems ◽  
Multi Objective ◽  
Design Engineers ◽  
Design Variables

Abstract Since tires carry out many functions and many of them have tradeoffs, it is important to find the combination of design variables that satisfy well-balanced performance in conceptual design stage. To find a good design of tires is to solve the multi-objective design problems, i.e., inverse problems. However, due to the lack of suitable solution techniques, such problems are converted into a single-objective optimization problem before being solved. Therefore, it is difficult to find the Pareto solutions of multi-objective design problems of tires. Recently, multi-objective evolutionary algorithms have become popular in many fields to find the Pareto solutions. In this paper, we propose a design procedure to solve multi-objective design problems as the comprehensive solver of inverse problems. At first, a multi-objective genetic algorithm (MOGA) is employed to find the Pareto solutions of tire performance, which are in multi-dimensional space of objective functions. Response surface method is also used to evaluate objective functions in the optimization process and can reduce CPU time dramatically. In addition, a self-organizing map (SOM) proposed by Kohonen is used to map Pareto solutions from high-dimensional objective space onto two-dimensional space. Using SOM, design engineers see easily the Pareto solutions of tire performance and can find suitable design plans. The SOM can be considered as an inverse function that defines the relation between Pareto solutions and design variables. To demonstrate the procedure, tire tread design is conducted. The objective of design is to improve uneven wear and wear life for both the front tire and the rear tire of a passenger car. Wear performance is evaluated by finite element analysis (FEA). Response surface is obtained by the design of experiments and FEA. Using both MOGA and SOM, we obtain a map of Pareto solutions. We can find suitable design plans that satisfy well-balanced performance on the map called “multi-performance map.” It helps tire design engineers to make their decision in conceptual design stage.

FROSTLINE

Alloy Digest ◽  
1977 ◽  
Vol 26 (3) ◽  
Keyword(s):  
Structural Design ◽  
Heat Treating ◽  
Carbon Steels ◽  
Carbon Equivalent ◽  
Low Carbon ◽  
Steel Company ◽  
Cold Temperatures ◽  
Fine Grain ◽  
Design Requirements ◽  
Treated Carbon

Abstract FROSTLINE is a fine-grain, columbium-treated carbon steel designed to be an economical solution to structural design requirements at cold temperatures. Available in plate thicknesses up to 6 inches, it offers high levels of toughness at temperatures to 80 F and higher strength levels than conventional carbon steels. Frostline also offers excellent welding characteristics, because of its low carbon equivalent. This datasheet provides information on composition, physical properties, elasticity, and tensile properties as well as fracture toughness. It also includes information on forming, heat treating, and machining. Filing Code: CS-67. Producer or source: Lukens Steel Company.

scholarly journals Structure Analysis and Design of Automobile plastic clutch pump body based on friction welding

2020 ◽  
Vol 316 ◽  
pp. 02001
Author(s):  
Jing Sheng ◽  
Aamir Sohail ◽  
Mengguang Wang ◽  
Zhimin Wang
Keyword(s):  
High Temperature ◽  
Structural Design ◽  
Friction Welding ◽  
Room Temperature ◽  
Welding Process ◽  
Structure Type ◽  
Mechanical Analysis ◽  
Analysis And Design ◽  
Technical Requirements ◽  
Design Requirements

In order to realize the need for lightweight automobiles through replacing steel with plastics, the research and development of the plastic clutch pump body based on the friction welding was carried out. For the clutch pump body connected by friction welding process between the upper pump body and the lower pump body, the technical requirements of pressure 14 MPa and durability (high temperature 7.0 × 104 times, room temperature 7.0 × 105) are required. The structure type of the upper and lower pump bodies of the end face welding type was proposed. Through the static analysis of the pump body and weld and the mechanical analysis under the working condition, the structure of the clutch pump body (upper and lower pump body) was determined. According to the established welding process, the pressure of the clutch pump body is more than 15 MPa, and the number of high-temperature durable circulation and the number of room temperature durable circulation also reached 7.2×104 and 7.3×105 times respectively. The results show that the structural design of a clutch pump body meets the design requirements.

Frequency optimization of laminated functionally graded carbon nanotube reinforced composite quadrilateral plates using smoothed FEM and evolution algorithm

2017 ◽  
Vol 52 (14) ◽  
pp. 1971-1986 ◽  
Author(s):  
T Vo-Duy ◽  
T Truong-Thi ◽  
V Ho-Huu ◽  
T Nguyen-Thoi
Keyword(s):  
Carbon Nanotube ◽  
Optimization Problem ◽  
Volume Fraction ◽  
Differential Evolution Algorithm ◽  
Composite Plates ◽  
Functionally Graded ◽  
Optimization Approach ◽  
Reinforced Composite ◽  
Design Variables ◽  
Evolution Algorithm

The paper presents an efficient numerical optimization approach to deal with the optimization problem for maximizing the fundamental frequency of laminated functionally graded carbon nanotube-reinforced composite quadrilateral plates. The proposed approach is a combination of the cell-based smoothed discrete shear gap method (CS-DSG3) for analyzing the first natural frequency of the functionally graded carbon nanotube reinforced composite plates and a global optimization algorithm, namely adaptive elitist differential evolution algorithm (aeDE), for solving the optimization problem. The design variables are the carbon nanotube orientation in the layers and constrained in the range of integer numbers belonging to [−900 900]. Several numerical examples are presented to investigate optimum design of quadrilateral laminated functionally graded carbon nanotube reinforced composite plates with various parameters such as carbon nanotube distribution, carbon nanotube volume fraction, boundary condition and number of layers.

Multi Objective Design Optimization of Two Bar Truss Using NSGA II and TOPSIS

2014 ◽  
Vol 984-985 ◽  
pp. 419-424
Author(s):  
P. Sabarinath ◽  
M.R. Thansekhar ◽  
R. Saravanan
Keyword(s):  
Design Optimization ◽  
Optimization Problems ◽  
Optimization Methods ◽  
Optimal Solutions ◽  
Objective Functions ◽  
Nsga Ii ◽  
Multi Objective ◽  
Total Displacement ◽  
Design Variables ◽  
Conflicting Objectives

Arriving optimal solutions is one of the important tasks in engineering design. Many real-world design optimization problems involve multiple conflicting objectives. The design variables are of continuous or discrete in nature. In general, for solving Multi Objective Optimization methods weight method is preferred. In this method, all the objective functions are converted into a single objective function by assigning suitable weights to each objective functions. The main drawback lies in the selection of proper weights. Recently, evolutionary algorithms are used to find the nondominated optimal solutions called as Pareto optimal front in a single run. In recent years, Non-dominated Sorting Genetic Algorithm II (NSGA-II) finds increasing applications in solving multi objective problems comprising of conflicting objectives because of low computational requirements, elitism and parameter-less sharing approach. In this work, we propose a methodology which integrates NSGA-II and Technique for Order Preference by Similarity to Ideal Solution (TOPSIS) for solving a two bar truss problem. NSGA-II searches for the Pareto set where two bar truss is evaluated in terms of minimizing the weight of the truss and minimizing the total displacement of the joint under the given load. Subsequently, TOPSIS selects the best compromise solution.

Multi-Objective Design Optimization of a Mixed-Flow Pump

2009 ◽  
Author(s):  
Yumiko Takayama ◽  
Hiroyoshi Watanabe
Keyword(s):  
Performance Characteristic ◽  
Performance Characteristics ◽  
Inverse Design ◽  
Surface Model ◽  
Objective Functions ◽  
Mixed Flow ◽  
Multi Objective ◽  
Design Variables ◽  
Flow Head ◽  
Flow Pump

In most cases of high specific speed mixed-flow pump applications, it is necessary to satisfy more than one performance characteristic such as deign point efficiency, shut-off power/head and non-stall characteristic (no positive slope in flow-head curve). However, it is known that these performance characteristics are in relation of trade-offs. As a result, it is difficult to optimize these performance characteristics by conventional way such as trial and error approach by modifying geometrical parameters. This paper presents the results of the multi-objective optimization strategy of mixed-flow pump design by means of three dimensional inverse design approach, Computational Fluid Dynamics (CFD), Design of Experiments (DoE), response surface model (RSM) and Multi Objective Genetic Algorism (MOGA). The parameters to control blade loading distributions and meridional geometries for impeller and diffuser blades in inverse design were chosen as design variables of the optimization process. Pump efficiency, maximum slope in flow-head curve and shut-off power/head were selected as objective functions. Objective functions of pumps, designed by design variables specified in DoE, were evaluated by using CFD. Then, trade-off relations between objective functions were analyzed by using Pareto fronts obtained by MOGA. Some pumps which have specific performance characteristic (non-stall, low shut-off power, high efficiency etc.) designed along the Pareto front were numerically evaluated.

Thermal Analysis on the Shell Stiffeners of Double Steel Wall LNG Storage Tank

2011 ◽  
Vol 105-107 ◽  
pp. 403-407
Author(s):  
Xiao Chun Zhang ◽  
Yuan Qi Cai
Keyword(s):  
Thermal Analysis ◽  
Structural Design ◽  
Storage Tank ◽  
Thermal Field ◽  
Local Buckling ◽  
Thermal Design ◽  
Normal Operation ◽  
Analysis Of Results ◽  
Design Requirements ◽  
Lng Tank

Shell stiffeners are used effectively to prevent preferential local buckling of LNG tank shell. In this paper, Finite element method (FEM) is applied to pay attention to the thermal analysis on the shell stiffeners of double steel wall LNG storage tank. The structural requirements according to British Standard 7777-2:1993 has been considered and then some dimensional adjustments of shell stiffeners are made to evaluate their influence on the thermal field of double steel wall LNG storage tank. Temperature distributions and heat flux of different dimensional shell stiffeners are presented. Though the analysis of results, it puts forward the conclusion that the dimensional design of shell stiffeners used in double steel wall LNG storage tank shall take not only the structural design requirements but also the thermal design ones into consideration in order to finally save cost in both construction and normal operation.

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