AN EXTENDED SUBSTRUCTURING TECHNIQUE FOR EFFICIENT EVALUATION OF NONLINEAR LOAD-BEARING STRUCTURES IN THE CONCEPTUAL DESIGN STAGE

2014 ◽  
Vol 11 (06) ◽  
pp. 1350086 ◽  
Author(s):  
MLADENKO KAJTAZ ◽  
ALEKSANDAR SUBIC ◽  
MONIR TAKLA

The research presented in this paper has extended the substructuring technique into the nonlinear domain in order to apply the finite element analysis (FEA) method to complex nonlinear structural design problems in the conceptual design stage. As conventional FE models based on substructures allow only linear analysis, it was necessary in this research to introduce a new algorithm capable of linearizing nonlinear structural problems with sufficient accuracy in order to enable evaluation of engineering design concepts in a more objective and rigorous manner in the early stages of design. The developed method was implemented within a commercial FE solver, and validated using a select number of case studies. The results obtained for the two sample solutions indicate that the new method has achieved an improvement in accuracy of 90% and 98% respectively compared to the conventional FE-based approach applied to the same class of design problems.

2013 ◽  
Vol 633 ◽  
pp. 15-35 ◽  
Author(s):  
Mladenko Kajtaz ◽  
Aleksandar Subic ◽  
Monir Takla

The paper presents a novel approach to comparative evaluation of engineering design concepts that exhibit non-linear structural behaviour under load. The developed method has extended the substructures technique in order to apply the Finite Element Analysis (FEA) method to complex non-linear structural problems in the conceptual design phase. As conventional FE models based on substructures allow only linear analysis, it was necessary in this research to introduce a new algorithm capable of linearizing non-linear structural problems with sufficient accuracy in order to enable comparative evaluation of design concepts relative to each other under the given constraints and loading conditions. A comparative study with respect to model size, efficiency, accuracy and confidence was performed to validate the developed method. Obtained results indicate significant improvement over more traditional approaches to applying FEA in the conceptual design phase. The improvements achieved using the developed method compared to the traditional FE based approach are superior by a factor of 2.7 in efficiency and by a factor of 4.5 in confidence while not sacrificing the optimality of the solutions.


2006 ◽  
Vol 34 (3) ◽  
pp. 170-194 ◽  
Author(s):  
M. Koishi ◽  
Z. Shida

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.


Energies ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3469
Author(s):  
Ji Han ◽  
Pingfei Jiang ◽  
Peter R. N. Childs

Although products can contribute to ecosystems positively, they can cause negative environmental impacts throughout their life cycles, from obtaining raw material, production, and use, to end of life. It is reported that most negative environmental impacts are decided at early design phases, which suggests that the determination of product sustainability should be considered as early as possible, such as during the conceptual design stage, when it is still possible to modify the design concept. However, most of the existing concept evaluation methods or tools are focused on assessing the feasibility or creativity of the concepts generated, lacking the measurements of sustainability of concepts. The paper explores key factors related to sustainable design with regard to environmental impacts, and describes a set of objective measures of sustainable product design concept evaluation, namely, material, production, use, and end of life. The rationales of the four metrics are discussed, with corresponding measurements. A case study is conducted to demonstrate the use and effectiveness of the metrics for evaluating product design concepts. The paper is the first study to explore the measurement of product design sustainability focusing on the conceptual design stage. It can be used as a guideline to measure the level of sustainability of product design concepts to support designers in developing sustainable products. Most significantly, it urges the considerations of sustainability design aspects at early design phases, and also provides a new research direction in concept evaluation regarding sustainability.


1981 ◽  
Vol 18 (01) ◽  
pp. 51-68
Author(s):  
Donald Liu ◽  
Abram Bakker

Local structural problems in ships are generally the result of stress concentrations in structural details. The intent of this paper is to show that costly repairs and lay-up time of a vessel can often be prevented, if these problem areas are recognized and investigated in the design stages. Such investigations can be performed for minimal labor and computer costs by using finite-element analysis techniques. Practical procedures for analyzing structural details are presented, including discussions of the results and the analysis costs expended. It is shown that the application of the finite-element analysis technique can be economically employed in the investigation of structural details.


2000 ◽  
Author(s):  
Yusheng Chen ◽  
Satyandra K. Gupta ◽  
Shaw Feng

Abstract This paper describes a web-based process/material advisory system that can be used during conceptual design. Given a set of design requirements for a part during conceptual design stage, our system produces process sequences that can meet the design requirements. Quite often during conceptual design stage, design requirements are not precisely defined. Therefore, we allow users to describe design requirements in terms of parameter ranges. Parameter ranges are used to capture uncertainties in design requirements. Our system accounts for uncertainties in design requirements in generating and evaluating process/material combinations. Our system uses a two step algorithm. During the first step, we generate a material/process option tree. This tree represents various process/material options that can be used to meet the given set of design requirements. During the second step, we evaluate various alternative process/material options using a depth first branch and bound algorithm to identify and recommend the least expensive process/material combination to the designer. Our system can be accessed on the World Wide Web using a standard browser. Our system allows designs to consider a wide variety of process/material options during the conceptual design stage and allows them to find the most cost-effective combination. By selecting the process/material combination during the early design stages, designers can ensure that the detailed design is compatible with all of the process constraints for the selected process.


2018 ◽  
Vol 2018 ◽  
pp. 1-17
Author(s):  
Jian Du ◽  
Yan Li ◽  
Jinlong Ma ◽  
Yan Xiong ◽  
Wenqiang Li

In the conceptual design stage, inspirational sources play an important role in designers’ creative thinking. This paper proposes a retrieval method for semantic-based inspirational sources, which helps designers obtain inspirational images in the conceptual design stage of emotional design. The core principle involves solving the designer’s own deficiencies in associations and limited knowledge, by bridging the “semantic gap” faced by designers when they use Kansei words for inspirational sources. This method can be divided into two aspects: (1) based on the semantic richness of Kansei words, the first part describes how a lexical ontology for Kansei words called KanseiNet is constructed and proposes a spreading activation mechanism based on KanseiNet to complete the semantic expansion of Kansei words; (2) the second part describes how, using existing semantic techniques, relevant design website resources are crawled and analyzed, images’ context descriptions and Kansei evaluations are extracted, and Kansei evaluation index of inspirational images is established. The KanseiNet for Chinese is first constructed, and the Sources of Inspiration Retrieval System for Emotional Design (SIRSED) is developed. An experiment comparing the existing image retrieval systems with SIRSED proved the latter to be a more comprehensive and accurate way for designers to access inspirational sources.


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