Reliabilitybased design optimization strategies based. The objective in this strategic decision area is to develop products that suit the organization. In system reliability design, there are two typical approaches that can enhance system reliability, namely. Several such tools are discussed in references 1 and 2. Comparing robust design optimization and reliability based. A survey on approaches for reliabilitybased optimization. Schematic illustration of the relation between a design variable x and the production cost, failure cost, and total cost of a product, respectively. Reliabilitybased design optimization for problems with interval distribution parameters article pdf available in structural and multidisciplinary optimization 1 june 2016 with 280 reads. Pdf threshold shift method for reliabilitybased design. Reliabilitybased design optimization method of turbine disk. Reliabilitybased design optimization strategies based on. About unilever unilever it is an multinational company, which includes dutch unilever nv in rotterdam and the british unilever plc, based in london. A multitude of methods have been proposed to alleviate this computational burden.
Unilever sees cae driven design and optimization as a means of ensuring the best technologies are adopted for meeting future challenges. Original contributions of this research are the development of a novel efficient and robust unilevel methodology for reliability based design optimization, the development of an innovative decoupled reliability based design optimization methodology, the application of homotopy techniques in unilevel reliability based design optimization. Reliability baseddesign optimization using the directional. On the other hand reliability based design optimization rbdo formulations have been using methods like first order reliability method form or second order reliability method sorm which require nested optimization to evaluate joint probability distribution and reliability factor. Dec 06, 20 unilever is a global consumer products manufacturer that achieved euro 50 billion turnover with over 173,000 employees in 2012 and its portfolio includes such famous brand names as dove, magnum, knorr, pg, hellmanns and others annual report and accounts, 2012. Homotopy methods for constraint relaxation in unilevel reliability based design optimization. Reliabilitybased design optimization rbdo has been used for optimizing engineering systems with uncertainties in design variables and system parameters. Pdf hybrid analysis method for reliabilitybased design.
Reliability based design optimization rbdo uses the mean values of the random system parameters as design variables, and optimizes the objective function subject to predefined probabilistic constraints such as failure probability or reliability index. Abstract in this paper, an algorithm for reliability based design optimization rbdo is presented. Reliability based optimization rbo for engineering design deals mainly with two design attributes, namely the merit, for example cost, and the reliability of the design. Unilever specifies its purpose as to make sustainable living commonplace. Its main feature is that it allows determining the best design solution with respect to prescribed criteria while explicitly considering the unavoidable effects of uncertainty. Structural optimization design considering reliability. Delivering innovation and intelligence in product design. Reliability based design optimization rbdo evaluates variation of output induced by uncertainties of design variables and results in an optimal design while satisfying the reliability requirements. A unilevel method for reliability based design optimization. Dimension reduction method for reliabilitybased robust. Reliabilitybased design optimization using a moment method and a. Chapter 1 reliability engineering basics and optimization techniques table of contents s.
We present a novel approach, referred to as the threshold shift method tsm, for reliability based design optimization rbdo. Confidencebased method for reliabilitybased design. Dimension reduction method for reliability based robust design optimization ikjin lee a, k. Reliabilitybased design optimization of a carbon fiberreinforced polymer bridge by. A multiobjective, reliabilitybased design optimization technique of a.
Reliability based optimization within the cad environment. Unilevers operations management considers the 10 strategic decisions for optimal productivity in all areas of the consumer goods business. Swot analysis of unilever name of the presenter md ikbal hussain anna dziegielewska kumrun nahar udara chinthaka fernando weerahannadige 2. In general, the application of this methodology is numerically involved, as it implies the simultaneous solution. Mar 23, 2007 a sequential optimization and reliability analysis strategy is used to solve rbdo with physics. The proposed method is illustrated by a mathematical example and a two. The objective of reliability based design optimization rbdo is to optimize structures guaranteeing that a minimum level of reliability, chosen a priori by the designer, is maintained.
Unilevers organizational culture of performance panmore. Here, the fast probabilistic integrator fpi module of the nessus. The unilever building and marco polo tower in hafencity, hamburg, germany in 2011. The resulting high performance ensures unilever s longterm success in the global consumer goods market. Robustnessbased design optimization under data uncertainty. A comparison between the results of the stochastic reliabilitybased method, the safety factorbased method, and the deterministic method show that the. Reliability baseddesign optimization rbdo is a methodology used in. However, simulation based optimization generates deterministic optimum. A reliability based optimization method for minimization the weight of tophat stiffened composite panels with probabilistic deflection constraints is presented in this paper. The optimization tools were coupled with models for multiphase fluid flow in reservoirs and surface pipeline networks through a commercial reservoir simulator.
In the 10 strategic decision areas of operations management, unilever focuses on high productivity through effectiveness and efficiency in business processes. Reliabilitybased design optimization for crashworthiness of. Reliabilitybased design optimization rbdo is a technique used for engineering design when uncertainty is being considered. Choi a, liu du a, david gorsich b a department of mechanical and industrial engineering, college of engineering, the university of iowa, iowa city, ia 52241, united states. Post optimization for accurate and efficient reliability.
The objective of this paper is the demonstration of an integrated cad based computeraided engineering process to effectively carry out design optimization for structural durability, yielding a durable and costeffectively manufacturable product. Methods for reliability based design optimization of structural components x failure cost production cost total cost cost design domain figure 2. Input model uncertainty and reliablity based design optimization with associated confidence level by yoojeong noh a thesis submitted in partial fulfillment of the requirements for the doctor of philosophy degree in mechanical engineering in the graduate college of the university of iowa december 2009 thesis supervisor. Pdf reliabilitybased design optimization for problems with. In this paper, we propose robustness based design optimization formulations that work under both aleatory and epistemic uncertainty using probabilistic representations of. Zeng meng, dixiong yang, huanlin zhou and bo yu, an accurate and efficient reliability based design optimization using the second order reliability method and improved stability transformation method, engineering optimization, 10. Reliability based design optimization rbdo methods are optimization algorithms that utilize reliability methods to evaluate probabilistic constraints andor objective functions used to prescribe. It has been widely recognized that engineering design should account for the stochastic nature of random parameters in engineered systems.
This is an active research topic and many authors have contributed so far. The traditional reliability based design optimization rbdo method deals with the uncertainties in product design variables by treating them as random variables and by formulating a probabilistic constraint on product performance function so as to satisfy its reliability or safety requirement. Reliabilitybased optimization is a most appropriate and advantageous methodology for structural design. In this work the class of design problems which are considered, are designs characterized by a minimum merit function and that satisfy certain reliability constraints. Enhancing product robustness in reliabilitybased design. Hybrid analysis method for reliability based design optimization.
For example, the results of evaluations are used for guiding hr practices that reinforce unilevers organizational culture of performance and quality. Unilever s operations management, 10 decision areas. These uncertainties play a dominant role in structural performance and the reliability based design optimization is a useful method to assess the uncertainty influence. Mar 25, 2017 unilever reinforces the corporate culture of performance and quality through leaders regular monitoring and evaluations, as well as commitment and support. Public domain unilevers operations management om is responsible for keeping high productivity throughout. A singleloop deterministic method for reliabilitybased design. The proposed approach is similar in spirit with the sequential. Input model uncertainty and reliabilitybased design. Timedependent reliability based design optimization rbdo has been acknowledged as an advance optimization methodology since it accounts for timevarying stochastic nature of systems. Stochastic subset optimization sso is a simulationbased approach recently proposed by ta. Compared to the basic deterministic based optimization problem, the latter considers additional nondeterministic constraint functions and will provide the structure more safety.
This paper proposes a timedependent rbdo method considering both of the timedependent kinematic reliability and the timedependent structural reliability as constrains. A thesis entitled an efficient method for reliability based design optimization when the design variables are random by zhong ren submitted to the graduate. Reliabilitybased design optimization of a composite airframe. Reliabilitybased design optimization using efficient global. Methods for reliability based design optimization of. Timedependent reliabilitybased design optimization. The practical application of reliabilitybased design optimization rbdo requires both. Therefore, there is a need for an efficient robust design optimization methodology that deals with both aleatory and epistemic uncertainty. In addition, the use of surrogate models andor multifidelity techniques. Reliabilitybased design optimization of a transonic. Reliabilitybased analysis and design optimization for.
Techniques for decoupling the optimization loops may be divided in two groups. Reliability based design optimization with experiments ondemand. Reliability based multiobjective optimization rbmo is a method that integrates multiobjective optimization with a reliability analysis. Since reliability analysis using the first order reliability method form is an optimization procedure itself. Reliabilitybased design optimization of wind turbine blades. Reliability index approach for a reliability based design, a performance function can be defined as g r s where r and s are. This paper presents a general approach for the probabilistic constraint evaluation in. Unilever is a global consumer products manufacturer that achieved euro 50 billion turnover with over 173,000 employees in 2012 and its portfolio includes such famous brand names as dove, magnum, knorr, pg, hellmanns and others annual report and accounts, 2012. Pdf benchmark study of numerical methods for reliability. Reliability based design optimization requires a probabilistic analysis tool.
Once again, most of them are based upon the assumption that the mpfp exists and that it is unique. Threshold shift method for reliabilitybased design optimization. The method is useful for a large or complicated design. Wind turbine blade, reliability based design optimization, fatigue life, wind load uncertainty 3. Benchmark study of numerical methods for reliability based design optimization. A new efficient unilevel formulation for reliability based design optimization was developed by the authors in earlier studies, where the lowerlevel optimization was replaced by its corresponding. Reliabilitybased optimization of the coupled structural. Reliabilitybased optimization for multidisciplinary system. Using the sampling based method, rbdo of the 5mw wind turbine blade is carried out starting at the ddo optimum design to meet the target probability of failure of 2. An energy based grillage method is developed for the investigation of buckling problems under bidirectional inplane loads. The reliability based design optimization rbdo methodologies not only provide improved designs but also a confidence range of the simulation based optimum designs.
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