Reliability and Robustness Based Design Attributes for Multi-Criteria Decision Making

2013 ◽  
Author(s):  
Vedran Žanić ◽  
Karlo Pirić ◽  
Stanislav Kitarović
Keyword(s):  
Design Methodology ◽  
Structural Model ◽  
Design Procedure ◽  
Design Parameters ◽  
Design System ◽  
Concept Design ◽  
Design Attributes ◽  
Standard Design ◽  
Reliability And Robustness ◽  
Panel Design

Novel design methodology with inclusion of reliability and robustness-based design criteria is presented. Robustness is defined as the insensitivity of a design attribute to uncontrollable design parameters. The developed design procedure for the concept design phase is divided into two basic, coordinated tasks: (1) multi-criteria topology/geometry optimization of the ship structural model; (2) scantlings / material multi-criteria optimization of structural panels. Reliability criteria and robustness of design attributes are applied as relative measures of quality, besides standard design attributes such as costs and weight. They are used in generation of Pareto-optimal design variants. Reliability attributes used for the panel design are compared with respect to fidelity and computational efficiency. A novel method for fast reliability calculations is presented using dimension reduction method (DRM) as implemented into FASTREL software. The method is verified with respect to accuracy and speed on the box girder design and panel design with CalREL methods (MC, FORM). The design procedure steps are executed in the predefined sequence of design sub-problems, using the fast and balanced collection of analysis and synthesis modules/methods of the MAESTRO/OCTOPUS design system. They are as follows: • Probabilistic determination of design loads; • Calculation of the structural serviceability and ultimate strength criteria on the panel (macro-element) level; • Calculation of the cross section ultimate longitudinal strength criterion; • Calculation of reliability and robustness measures on the panel level (safety) and on the global level. Other design attributes (initial cost, structural weight, etc.) are also determined; • Generation of the Pareto frontier for the selected test structure based upon the cost–safety design paradigm; • Generation of insight into the multilevel optimization process with graphic presentation of designs in design and attribute spaces. Practical application of the developed concept design methodology and of the design environment to the structural design of modern multi-deck ship elements (panels) is presented for verification/validation of accuracy and speed of FASTREL module.

Development and Application of a Multi-Disciplinary Multi-Regime Design Methodology of a Low-Noise Contra-Rotating Open-Rotor

2015 ◽  
Author(s):  
Michaël Leborgne ◽  
Timothée Lonfils ◽  
Ingrid Lepot
Keyword(s):  
Noise Reduction ◽  
High Speed ◽  
Design Methodology ◽  
Design Procedure ◽  
Low Noise ◽  
Design Parameters ◽  
Mechanical Constraints ◽  
Open Rotor ◽  
Mechanical Optimization ◽  
Lifting Line

This paper focuses on the development and exploitation of a multi-disciplinary, optimization-assisted, design methodology for contra-rotating open-rotors. The design procedure relies on a two-step approach. An aero-mechanical optimization is first performed to generate a geometry with good performances over several high-speed points representative of a mission. This geometry is subsequently used as the baseline of an aero-mechanical-acoustic optimization focusing on interaction noise reduction at Cutback and Sideline low-speed points. In terms of design parameters, both rotors are modified for the first phase but only the upper part of the front rotor is altered for the noise minimization. A fully-automatic high-fidelity aero-mechanical-acoustic computational chain with fluid-structure coupling is exploited in combination with evolutionary algorithms assisted by surrogate models for the constrained-optimization process. The acoustic footprint is estimated by a simplified but fast and relevant formulation combining an unsteady lifting-line and an acoustic propagation method. The best geometry of the first design gains 1.2pt in weighted efficiency while respecting all the aero-mechanical constraints. The acoustic optimization shows that noise reduction at Sideline and Cutback points is strongly antagonistic. However, significant Sideline noise reduction from 3.5 to 5.5dB depending on the harmonics is achieved while maintaining Cutback noise and without major degradation of high-speed efficiency.

Development of an Automated Preliminary Combustion Chamber Design Tool

2006 ◽  
Author(s):  
Nima Pegemanyfar ◽  
Michael Pfitzner ◽  
Ruud Eggels ◽  
Ralf von der Bank ◽  
Marco Zedda
Keyword(s):  
Combustion Chamber ◽  
Design Methodology ◽  
Design Tool ◽  
Design Parameters ◽  
Design System ◽  
Engineering System ◽  
Cad Model ◽  
Preliminary Design ◽  
Design Rules ◽  
Knowledge Based

The preliminary design of a new combustion chamber requires the combination of many elements of know-how in terms of combustor design rules, aerothermal calculations and preliminary design tools. To use this knowledge more efficiently pre-competitive work on an automated knowledge-based combustor design methodology is done within the European project INTELLECT D.M. (Integrated Lean Low Emission Combustor Design Methodology) in order to set up a KBE (Knowledge Based Engineering) system. In the method presented here, the rules and calculation routines are implemented into an automated preliminary design system using an Excel-driven database to generate a parametric Unigraphics CAD model. The utilized design rules represent state-of-the-art combustor design and will be extended later by lean combustion design rules, which are currently developed within INTELLECT D.M.. The database contains all design parameters and rules to provide CAD, CFD and optimization tools with the required information. Based on a set of performance parameters the system automatically generates the parametric geometry of a combustor containing the liners with cooling devices (optionally Z-ring or effusion cooling) and mixing holes, heat shield, cowl, casings and (pre)diffusor. To estimate the required cooling air, one-dimensional heat transfer equations including convection, radiation and conduction are solved. The generated CAD model visualizes the calculated combustor geometry and forms the basis for an automated CFD mesh generation utilizing the grid generator ICEM CFD.

Safety as Objective in Multicriterial Structural Optimization

2010 ◽  
Author(s):  
Vedran Zanic ◽  
Stanislav Kitarovic ◽  
Pero Prebeg
Keyword(s):  
Failure Modes ◽  
Design Procedure ◽  
Material Design ◽  
Design System ◽  
Stiffened Panel ◽  
Safety Measures ◽  
Multicriterial Optimization ◽  
Design Variables ◽  
Standard Design ◽  
Longitudinal Strength

Multicriterial design methodology with safety as one of the design objectives is presented. The aim of the paper is to analyze the influence of safety based design objectives on generated nondominated designs on the Pareto frontier. Possible improvements in nondominated designs are investigated by comparison to ones obtained with the standard design procedure when safety criteria are used as design constraints only. It is assumed that safety based objectives and targets act as attractors, driving nondominated designs along the constant cost/weight contours in design space towards its safer regions. Global safety objectives (for hogging/sagging modes), are based on the maximization of ultimate longitudinal strength in vertical bending calculated via the extended IACS incremental-iterative method. Applied compound safety measures for gross-panel (stiffened panel with associated girders) are based upon 34 failure modes, belonging to serviceability/collapse subsets. Objectives based on the maximization of safety measures are applied together with standard design objectives such as minimization of initial cost and weight. The following problems were solved with different sets of objectives: (a) minimize cost and weight objectives subject to safety constraints (used for reference), (b) only the maximization of local safety measures is added to (a) as additional objectives, (c) only the maximization of global safety measures is added to (a) as additional objectives, (d) maximization of safety measures ad (b) and (c) are added to (a) as additional objectives. For each of the problems (a–d) the developed design procedure is executed. It contains two basic tasks for structural design of realistic (non-academic) problems: (1) multicriterial optimization with topology / geometry design variables; (2) multicriterial optimization of gross-panels with scantling / material design variables. Design procedure steps are executed using a fast and balanced collection of analysis and synthesis modules/methods of the OCTOPUS design system: • Determination of design load sets; • MOGA / MOPSO based generation of nondominated designs for the selected ship structure; • For each design the following analysis blocks are executed: – calculation of ship’s primary and racking response fields, – calculation of ship’s ultimate longitudinal strength, – calculation of serviceability and collapse safety criteria on the gross-panel level. Comparisons of results, based on generated Pareto hyper-surfaces and on subset of preferred designs, are given for problems (a–d). Insights into the results of optimization process, using 5-D graphics for design and attribute spaces, are also presented. Design problems of modern RoPax and SWATH structures are used in case studies.

scholarly journals Rationality Analysis of High-rise Building Structure Calculation un- der SATWE Procedure

1970 ◽  
Vol 1 (1) ◽  
Author(s):  
Fan Guiqing
Keyword(s):  
Structural Design ◽  
Structural Model ◽  
Design Procedure ◽  
Design Parameters ◽  
Land Resources ◽  
High Rise ◽  
Structural Problems ◽  
Seismic Force ◽  
Structural Calculation ◽  
Capital Construction

In recent years, with the increasing shortage of land resources in our country, in or der to make full use of limited land resources, the development of construction industry is developing towards high-rise and super-high-rise buildings.This is based on the use of structural design and structural calculation of building structures with the higher requirement. For structural designers, the structural model is determined reasonably, the structural design procedure is used correctly, the design parameters and seismic force parameters are accurately input, the results are correctly analyzed and the structural calculation model is adjusted according to the calcu- lated results. Repeated adjustments in order to design safe high-rise buildings, so that the capital construction investmenthas been rationally used. In this paper, how to use the SATWE program developed by China Academy of Building Science to study the structural calculation and structural problems, how to analyze the calculation results and use the calculated results to reflect the problem and then adjust the structural model and other issues to study.

scholarly journals A modular design method based on TRIZ and AD and its application to cutter changing robot

2021 ◽  
Vol 13 (7) ◽  
pp. 168781402110343
Author(s):  
Mei Yang ◽  
Yimin Xia ◽  
Lianhui Jia ◽  
Dujuan Wang ◽  
Zhiyong Ji
Keyword(s):  
Modular Design ◽  
Design Method ◽  
Idea Generation ◽  
Design Parameters ◽  
Problem Analysis ◽  
Concept Design ◽  
Functional Requirements ◽  
Shield Tunneling ◽  
Structural Hierarchy ◽  
And Performance

Modular design, Axiomatic design (AD) and Theory of inventive problem solving (TRIZ) have been increasingly popularized in concept design of modern mechanical product. Each method has their own advantages and drawbacks. The benefit of modular design is reducing the product design period, and AD has the capability of problem analysis, while TRIZ’s expertise is innovative idea generation. According to the complementarity of these three approaches, an innovative and systematic methodology is proposed to design big complex mechanical system. Firstly, the module partition is executed based on scenario decomposition. Then, the behavior attributes of modules are listed to find the design contradiction, including motion form, spatial constraints, and performance requirements. TRIZ tools are employed to deal with the contradictions between behavior attributes. The decomposition and mapping of functional requirements and design parameters are carried out to construct the structural hierarchy of each module. Then, modules are integrated considering the connections between each other. Finally, the operation steps in application scenario are designed in temporal and spatial dimensions. Design of cutter changing robot for shield tunneling machine is taken as an example to validate the feasibility and effectiveness of the proposed method.

scholarly journals Robust H∞ Loop Shaping Controller Synthesis for SISO Systems by Complex Modular Functions

2021 ◽  
Vol 26 (1) ◽  
pp. 21
Author(s):  
Ahmad Taher Azar ◽  
Fernando E. Serrano ◽  
Nashwa Ahmad Kamal
Keyword(s):  
Design Methodology ◽  
Closed Loop ◽  
Complex Analysis ◽  
Controller Design ◽  
Filter Design ◽  
Design Procedure ◽  
Elliptic Functions ◽  
Loop System ◽  
Closed Loop System ◽  
Loop Shaping

In this paper, a loop shaping controller design methodology for single input and a single output (SISO) system is proposed. The theoretical background for this approach is based on complex elliptic functions which allow a flexible design of a SISO controller considering that elliptic functions have a double periodicity. The gain and phase margins of the closed-loop system can be selected appropriately with this new loop shaping design procedure. The loop shaping design methodology consists of implementing suitable filters to obtain a desired frequency response of the closed-loop system by selecting appropriate poles and zeros by the Abel theorem that are fundamental in the theory of the elliptic functions. The elliptic function properties are implemented to facilitate the loop shaping controller design along with their fundamental background and contributions from the complex analysis that are very useful in the automatic control field. Finally, apart from the filter design, a PID controller loop shaping synthesis is proposed implementing a similar design procedure as the first part of this study.

Acoustic meta-silencer: Toward enabling ultrawide-band air-permeable noise barrier

2021 ◽  
pp. 107754632110011
Author(s):  
Mohammad Javad Khodaei ◽  
Amin Mehrvarz ◽  
Reza Ghaffarivardavagh ◽  
Nader Jalili
Keyword(s):  
Heat Transfer ◽  
Design Methodology ◽  
Heat Transfer Performance ◽  
Transmission Loss ◽  
Design Parameters ◽  
Transfer Performance ◽  
Noise Mitigation ◽  
Acoustic Cavity ◽  
Road Map ◽  
Noise Barrier

In this article, we have first presented a metasurface design methodology by coupling the acoustic cavity to the coiled channel. The geometrical design parameters in this structure are subsequently studied both analytically and numerically to identify a road map for silencer design. Next, upon tuning the design parameters, we have introduced an air-permeable noise barrier capable of sound silencing in the ultrawide band of the frequency. It is has been shown that the presented metasurface can achieve +10 dB sound transmission loss from 170 Hz to 1330 Hz (≈3 octaves). Furthermore, we have numerically studied the ventilation and heat transfer performance of the designed metasurface. Enabling noise mitigation by leveraging the proposed metasurface opens up new possibilities ranging from residential and office noise reduction to enabling ultralow noise fan, propellers, and machinery.

scholarly journals A Two-Round Optimization Design Method for Aerostatic Spindles Considering the Fluid–Structure Interaction Effect

2021 ◽  
Vol 11 (7) ◽  
pp. 3017
Author(s):  
Qiang Gao ◽  
Siyu Gao ◽  
Lihua Lu ◽  
Min Zhu ◽  
Feihu Zhang
Keyword(s):  
Optimal Design ◽  
Optimization Design ◽  
Design Method ◽  
Fluid Structure Interaction ◽  
Design Procedure ◽  
Design Parameters ◽  
Geometrical Parameters ◽  
Fluid Structure ◽  
Structure Interaction ◽  
Aerostatic Spindle

The fluid–structure interaction (FSI) effect has a significant impact on the static and dynamic performance of aerostatic spindles, which should be fully considered when developing a new product. To enhance the overall performance of aerostatic spindles, a two-round optimization design method for aerostatic spindles considering the FSI effect is proposed in this article. An aerostatic spindle is optimized to elaborate the design procedure of the proposed method. In the first-round design, the geometrical parameters of the aerostatic bearing were optimized to improve its stiffness. Then, the key structural dimension of the aerostatic spindle is optimized in the second-round design to improve the natural frequency of the spindle. Finally, optimal design parameters are acquired and experimentally verified. This research guides the optimal design of aerostatic spindles considering the FSI effect.

scholarly journals Displacement-based design of precast hinged portal frames with additional dissipating devices at beam-to-column joints

2021 ◽  
Author(s):  
Andrea Belleri ◽  
Simone Labò
Keyword(s):  
Design Methodology ◽  
Linear Time ◽  
Design Procedure ◽  
Time History ◽  
Structural System ◽  
Additional Degree ◽  
Speed Up ◽  
Column Joint ◽  
Displacement Based ◽  
Mechanical Devices

AbstractThe seismic performance of precast portal frames typical of the industrial and commercial sector could be generally improved by providing additional mechanical devices at the beam-to-column joint. Such devices could provide an additional degree of fixity and energy dissipation in a joint generally characterized by a dry hinged connection, adopted to speed-up the construction phase. Another advantage of placing additional devices at the beam-to-column joint is the possibility to act as a fuse, concentrating the seismic damage on few sacrificial and replaceable elements. A procedure to design precast portal frames adopting additional devices is provided herein. The procedure moves from the Displacement-Based Design methodology proposed by M.J.N. Priestley, and it is applicable for both the design of new structures and the retrofit of existing ones. After the derivation of the required analytical formulations, the procedure is applied to select the additional devices for a new and an existing structural system. The validation through non-linear time history analyses allows to highlight the advantages and drawbacks of the considered devices and to prove the effectiveness of the proposed design procedure.

Momentum exchange impact damper design methodology for object-wall-collision problems

2017 ◽  
Vol 24 (14) ◽  
pp. 3206-3218
Author(s):  
Yohei Kushida ◽  
Hiroaki Umehara ◽  
Susumu Hara ◽  
Keisuke Yamada
Keyword(s):  
Optimal Design ◽  
Design Methodology ◽  
Design Parameters ◽  
Momentum Exchange ◽  
Impact Damper ◽  
One Dimensional ◽  
Practical Design ◽  
Wall Collision ◽  
Damper Design ◽  
And Control

Momentum exchange impact dampers (MEIDs) were proposed to control the shock responses of mechanical structures. They were applied to reduce floor shock vibrations and control lunar/planetary exploration spacecraft landings. MEIDs are required to control an object’s velocity and displacement, especially for applications involving spacecraft landing. Previous studies verified numerous MEID performances through various types of simulations and experiments. However, previous studies discussing the optimal design methodology for MEIDs are limited. This study explicitly derived the optimal design parameters of MEIDs, which control the controlled object’s displacement and velocity to zero in one-dimensional motion. In addition, the study derived sub-optimal design parameters to control the controlled object’s velocity within a reasonable approximation to derive a practical design methodology for MEIDs. The derived sub-optimal design methodology could also be applied to MEIDs in two-dimensional motion. Furthermore, simulations conducted in the study verified the performances of MEIDs with optimal/sub-optimal design parameters.

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