Lessons learned from the “5.12” Wenchuan Earthquake:evaluation of earthquake performance objectives and the importance of seismic conceptual design principles

Many different types of buildings were severely damaged or collapsed during the May 12, 2008 Great Wenchuan Earthquake. Based on survey data collected in regions that were subjected to moderate to severe earthquake intensities, a comparison between the observed building damage, and the three earthquake performance objectives and seismic conceptual design principles specified by the national ＂Code for Seismic Design of Buildings GB50011-2001,＂ was carried out. Actual damage and predicted damage for a given earthquake level for different types of structures is compared. Discussions on seismic conceptual design principles, with respect to multiple defense lines, strong column-weak beam, link beam of shear walls, ductility detailing of masonry structures, exits and staircases, and nonstructural elements, etc. are carried out. Suggestions for improving the seismic design of structures are also proposed. It is concluded that the seismic performance objectives for three earthquake levels, i.e., ＂no failure under minor earthquake level, ＂＂repairable damage under moderate earthquake level＂ and ＂no collapse under major earthquake level＂ can be achieved if seismic design principles are carried out by strictly following the code requirements and ensuring construction quality.

CASE-BASED CONCEPTUAL DESIGN

The current method of case-based design (CBD) can be well practiced forconfiguration design in which design experience knowledge is involved. However, since the designcase is confined to a certain application domain, it is difficult for CBD to be applied toconceptual design process that develops concepts to meet design specifications. Firstly, a functionfactor description space is erected to provide an exhibition room for all functions of design cases.Next, the approach for identifying the space state of function factor in description space isproposed, including the determination of the similarities between function factors of design case.And then a general object-oriented representation for design case is presented by bringing the classof function and in-out flow into the current case representation. Finally, a living example forelectro-pet design that illustrates the implementation of the method for case-based conceptualdesign based on distributed design case repositories is described.

MECHANICAL PRODUCT EXTENSIVE INTELLIGENT CONCEPTUAL DESIGN

Based on extenics, an extensive functional information model(function-behavioral action-structure-environmental constraint) of the mechanical productintelligent conceptual design is developed, and the mechanism of theoretic structure solutions isproduced, the mapping relations between function-behavior and behavior-structure are analyzed. Themodel is applied to the filling material system's conceptual design to verify validity.

A New Method for Optimum Allocation of Design Requirements in Aircraft Conceptual Design

A new method, Collaborative Allocation （CA）, is proposed to solve the large-scale optimum allocation problem in aircraft conceptual design. According to the characteristics of optimum allocation in aircraft conceptual design. The principle and mathematical model of CA are established. The optimum allocation problem is decomposed into one main optimization problem and several sub-optimization problems. A group of design requirements for subsystems are provided by the main system respectively, and the subsystems execute their own optimizations or further provide the detailed design requirements to the bottom components of aircraft, such as spars, ribs and skins, etc. The subsystems minimize the discrepancy between their own local variables and the corresponding allocated values, and then return the optimization results to main optimization. The main optimization is performed to reallocate the design requirements for improving the integration performance and progressing toward the compatibilities among subsystems. CA provides the general optimum allocation architecture and is easy to be carried out. Furthermore, the concurrent computation can also be realized. Two examples of optimum reliability allocation are used to describe the implementation procedure of CA for two-level allocation and three-level allocation respectively, and to validate preliminarily its correctness and effectiveness. It is shown that the developed method can be successfully used in optimum allocation of design requirements. Then taking weight requirement allocation as example, the mathematical model and solution procedure for collaborative allocation of design requirements in aircraft conceptual design are briefly depicted.

AUTOMATIC APPROACH TO PRODUCT CONCEPTUAL DESIGN BASED ON CONSTRAINT NETWORK

Product design is considered as the constraint satisfaction problem (CSP),and a new design approach basedon constraint network is proposed and applied to make designautomatic partially. By means of constraint extraction, constraint network construction andoperation, constraint chains are acquired, and then the conceptual design scheme can be got bydecoding the information stored in the design constraint chains, which provides a novelty method formechanical product design automation. Shearing mechanism of shearing machine has been designed bythis way.

Logical-Structure Modeling for Conceptual Design

Based on the definition of a logic structure feature to relate logically functional requirements to geometric representation independent upon detailed geometric representation, this paper presents an idea of logical structure modeling for computer aided conceptual design and makes attempt to establish a representation formalism of logic structure modeling. The definition and representation of logical structure feature are given and an assembly module definition for supporting top down conceptual design is also proposed. The proposed scheme contributes to several aspects of conceptual design research, especially to provide elementarily a formal methodology for computer aided conceptual design system development and operation.

Systems engineering optimization of Omid-2 in the conceptual design phase

Due to the importance and role of systems engineering in space mission developments, optimization of Omid＇s systems engineering as a milestone to its current and future generations is focused. In this regard systems engineering management organization as the basis of optimization work flow in the conceptual design phase is proposed for improvement. To improve the systems engineering management, an agile enhanced organization chart is developed that defines various system duties. This is a type of concurrent engineering approach that promotes direct communication and data interchange between the team members. Due to the importance of decision making in the conceptual design phase, two design matrices are constructed that portray merits of various design options in terms of improved satellite life as well as specific choices of remote sensing capability for the Omid second generation（Omid-2）. Conceptual design optimization is explored considering several structural objectives as well as optimal solar energy absorption utilizing a multiple criteria decision making approach. The Eigenvector method is utilized to formulate the objective function via expert judgment. This approach is robust with respect to designer probable miss-judgment. The optimized version of Omid-2 turned out to be a passive Z-axis spin stabilized satellite made of hexagonal honeycomb configuration with carbon-epoxy side panels and Aluminum bottom plate.

Extractive distillation: Advances in conceptual design, solvent selection,and separation strategies

Extractive distillation(ED) is one of the most promising approaches for the separation of the azeotropic or closeboiling mixtures in the chemical industry. The purpose of this paper is to provide a broad overview of the recent development of key aspects in the ED process involving conceptual design, solvent selection, and separation strategies. To obtain the minimum entrainer feed flow rate and reflux ratio for the ED process, the conceptual design of azeotropic mixture separation based on a topological analysis via thermodynamic feasibility insights involving residue curve maps, univolatility lines, and unidistribution curves is presented. The method is applicable to arbitrary multicomponent mixtures and allows direct screening of design alternatives. The determination of a suitable solvent is one of the key steps to ensure an effective and economical ED process. Candidate entrainers can be obtained from heuristics or literature studies while computer aided molecular design(CAMD) has superiority in efficiency and reliability. To achieve optimized extractive distillation systems, a brief review of evaluation method for both entrainer design and selection through CAMD is presented. Extractive distillation can be operated either in continuous extractive distillation(CED) or batch extractive distillation(BED), and both modes have been well-studied depending on the advantages in flexibility and low capital costs. To improve the energy efficiency, several configurations and technological alternatives can be used for both CED and BED depending on strategies and main azeotropic feeds. The challenge and chance of the further ED development involving screening the best potential solvents and exploring the energy-intensive separation strategies are discussed aiming at promoting the industrial application of this environmentally friendly separation technique.

Computer-based Creativity Enhanced Conceptual Design Model for Non-routine Design of Mechanical Systems

Computer-based conceptual design for routine design has made great strides, yet non-routine design has not been given due attention, and it is still poorly automated. Considering that the function-behavior-structure（FBS） model is widely used for modeling the conceptual design process, a computer-based creativity enhanced conceptual design model（CECD） for non-routine design of mechanical systems is presented. In the model, the leaf functions in the FBS model are decomposed into and represented with fine-grain basic operation actions（BOA）, and the corresponding BOA set in the function domain is then constructed. Choosing building blocks from the database, and expressing their multiple functions with BOAs, the BOA set in the structure domain is formed. Through rule-based dynamic partition of the BOA set in the function domain, many variants of regenerated functional schemes are generated. For enhancing the capability to introduce new design variables into the conceptual design process, and dig out more innovative physical structure schemes, the indirect function-structure matching strategy based on reconstructing the combined structure schemes is adopted. By adjusting the tightness of the partition rules and the granularity of the divided BOA subsets, and making full use of the main function and secondary functions of each basic structure in the process of reconstructing of the physical structures, new design variables and variants are introduced into the physical structure scheme reconstructing process, and a great number of simpler physical structure schemes to accomplish the overall function organically are figured out. The creativity enhanced conceptual design model presented has a dominant capability in introducing new deign variables in function domain and digging out simpler physical structures to accomplish the overall function, therefore it can be utilized to solve non-routine conceptual design problem.

Multi-objective Optimization Conceptual Design of Product Structure Based on Variable Length Gene Expression

It is a complicated problem for the bottom-to-top adaptive conceptual design of complicated products between structure and function. Reliable theories demand to be found in order to determine whether the structure accords with the requirement of design. For the requirement generally is dynamic variety as time passes, new requirements will come, and some initial requirements can no longer be used. The number of product requirements, the gene length expressing requirements, the structure of the product, and the correlation matrix are varied with individuation of customer requirements of the product. By researching on the calculation mechanisms of dynamic variety, the approaches of gene expression and variable length gene expression are proposed. According to the diversity of structure selection in conceptual design and mutual relations between structure and function as well as structure and structure, the correlation matrixes between structure and function as well as structure and structure are defined. By the approach of making the sum of the elements of correlation matrix maximum, the mathematical models of multi-object optimization for structure design are provided based on variable requirements. An improved genetic algorithm called segment genetic algorithm is proposed based on optimization preservation simple genetic algorithm. The models of multi-object optimization are calculated by the segment genetic algorithm and hybrid genetic algorithm. An example for the conceptual design of a washing machine is given to show that the proposed method is able to realize the optimization structure design fitting for variable requirements. In addition, the proposed approach can provide good Pareto optimization solutions, and the individuation customer requirements for structures of products are able to be resolved effectively.

The Conceptual Design Method for a Pumping Unit Based on QFD and TRIZ

Quality function deployment （QFD） is a quality system, that can help to design novel products that meet customers＇ needs. Theory of inventive problem solving （TRIZ） is a very powerful tool in helping to solve difficult technical problems encountered in the design process. Introducing QFD and TRIZ into the conceptual design of the pumping unit combines advantages of these two theories, therefore meeting different demands of different users. It can tell us “What should we do it” with QFD and “How should we do it” with TRIZ. The conceptual design method, which is based on QFD and TRIZ, is introduced andused to analyze and evaluate the conceptual design project of a pumping unit.

A Signed Digraphs Based Method for Detecting Inherently Unsafe Factors of Chemical Process at Conceptual Design Stage

Digraph-based causal models have been widely used to model the cause and effect behavior of process systems. Signed digraphs （SDG） capture the direction of the effect. It should be mentioned that there are loops in SDG generated from chemical process. From the point of the inherent operability, the worst unsafe factor is the SDG having positive loops that means any disturbance occurring within the loop will propagate through the nodes one by one and are amplified gradually, so the system may lose control, which may lead to an accident. So finding the positive loops in a SDG and treating these unsafe factors in a proper manner can improve the inherent safety of a chemical process. This article proposed a method that can detect the above-mentioned unsafe factors in the proc- ess conceptual design stage automatically through the analysis of the SDG generated from the chemical process. A case study is illustrated to show the working of the algorithm, and then a complicated case from industry is studied to depict the effectiveness of the proposed algorithm.

A Computational Synthesis Approach of Mechanical Conceptual Design Based on Graph Theory and Polynomial Operation

The design synthesis is the key issue in the mechanical conceptual design to generate the design candidates that meet the design requirements.This paper devotes to propose a novel and computable synthesis approach of mechanisms based on graph theory and polynomial operation.The graph framework of the synthesis approach is built firstly,and it involves:(1)the kinematic function units extracted from mechanisms;(2)the kinematic link graph that transforms the synthesis problem from mechanical domain into graph domain;(3)two graph representations,i.e.,walk representation and path representation,of design candidates;(4)a weighted matrix theorem that transforms the synthesis process into polynomial operation.Then,the formulas and algorithm to the polynomial operation are presented.Based on them,the computational flowchart to the synthesis approach is summarized.A design example is used to validate and illustrate the synthesis approach in detail.The proposed synthesis approach is not only supportive to enumerate the design candidates to the conceptual design of a mechanical system exhaustively and automatically,but also helpful to make that enumeration process computable.

A Preliminary study on the seismic conceptual design

The seismic conceptual design is an essential part of seismic design codes. It points out that the term 'seismic conceptual design' should imply three aspects,i.e.,the given concept itself,the specific provisions related to the given concept and the designing following the provisions. Seismic conceptual design can be classified into two categories: the strict or traditional seismic conceptual design and the generalized seismic conceptual design. The authors are trying to define for both conceptual designs their connotations and study their characteristics,in particular,the differences between them. Authors emphasize that both conceptual designs sound very close,however,their differences are apparent. The strict conceptual designs are usually worked out directly from engineering practice and/or lessons learnt from earthquake damage,while the generalized conceptual designs are resulted in a series of visions aiming to realize the general objectives of the seismic codes. The strict conceptual designs,(traditional conceptual designs) are indispensable elements of seismic codes in assuring designed structures safer and the generalized conceptual designs are playing key roles in directing to a more advanced and effective seismic codes.

Evaluating the conceptual design schemes of complex products based on FAHP using fuzzy number

In the conceptual design stage of complex products, CBR（Case-Based Reasoning） tool is useful to offer a feasible set of schemes. Then the most adaptive scheme can be generated through a procedure of comparison and evaluation. The procedure is essentially a multiple criteria decision-making problem. The traditional multiple criteria programming is not flexible enough in executing the system evaluation algorithm due to both the limited experimental data and the lack of human experiences. To make the CBR tool to be more efficient, a new method for the best choice among the feasible schemes based on the Fuzzy AHP using Fuzzy numbers （FFAHP） is proposed. Since the final results become a problem of ranking the mean of fuzzy numbers by the optimism of decision-maker using the FFAHP, its execution is much more intuitive and effective than with the traditional method.

Web-Based Interactive VR-CAD System for Conceptual Design and Analysis

To overcome the bottleneck of the one-way translation from VR （ virtual reality） to CAD in VR-based CAD system, this paper proposes a Web-based VR-CAD system WVCD （ Web-based virtual conceptual designer） to support both customers＇and design team members＇involvement in the conceptual design and analysis activity over the Internet. It provides users with both parametric and freehand methods to create and edit 3D conceptual models with different levels of complexity in a VR environment intuitively without the need of switching between the VR environment and CAD tools. As a simple and low-cost VR-CAD system, WVCD can help to popularize and improve the Web-based collaborative conceptual design.

Analysis of solution findings in the conceptual design of function structures

In the conceptual stage the function design process is realized by the computer aided application. After surveying on the function specification methods and the function modeling, a computer aided function design environment is analyzed. Subsequently based on a module library and principle catalogue, a solution finding process as a part of conceptual design is proposed for a creative design. In addition, a search algorithm to find the solution of adaptable function structure is also discussed. The concepts proposed in this paper can support the subsequent design stages, especially simulation for checking the function structure defects.

Integration of axiomatic design and theory of inventive problem solving for conceptual design

Axiomatic design (AD) and theory of inventive problem solving (TRIZ) are widely used in conceptual design. Both of them have limitations, however. We presented an integrated model of these two methods to increase the efficiency and quality of the problem solving process for conceptual design. AD is used for systematically defining and structuring a problem into a hierarchy. Sometimes, the design matrix is coupled in AD which indicates the functional requirements are coupled. TRIZ separation principles can be used to separate non-independent design parameters, which provide innovative solutions at each hierarchical level. We applied the integrated model to the heating and drying equipment of bitumen reproduction device. The result verifies that the integrated model can work very well in conceptual design.

Application of Hopfield Neural Networks Approach in Solar Energy Product Conceptual Design

A new product conceptual design approach is put forward based on Hopfield neural networks models. By research on the mechanisms of Hopfield neural networks, the associative simulation approaches are proposed. The approach is given by Hebb learn- ing law, Hopfield neural networks and crossover and mutation. The calculating models and the calculating formulas for the concep- tual design are put forward. Finally, an example for the conceptual design of a solar energy lamp is given. The better results are ob- tained in the conceptual design.

A Multidisciplinary Design Optimization Model for AUV Synthetic Conceptual Design

Autonomous undersea vehicle (AUV) is a typical complex engineering system. This paper studies the disciplines and coupled variables in AUV design with multidisciplinary design optimization (MDO) methods. The framework of AUV synthetic conceptual design is described first, and then a model with collaborative optimization is studied. At last, an example is given to verify the validity and efficiency of MDO in AUV synthetic conceptual design.