Enabling exploration in the conceptual design and optimisation of complex systems

Abstract

In this paper, a design support framework for handling complexity associated with design exploration is presented. Two enabling methods are proposed. The first is a novel algorithm for dependency analysis of computational workflows. It provides a means for guiding the designer in adequately reversing the inputs and outputs of models and workflows, depending on the particular formulation(s) of the design studies to be conducted. Ultimately, the algorithm is intended to enable the (re)configuration of workflows while guaranteeing solvability. A method for supporting the investigation of what-if studies is also proposed. It is based on a generalisation of the isocontour method aimed at analysing the effects of different definitions of the design variable bounds on the topology of the feasible design space. The methodology is demonstrated by an industrially relevant test case concerning aircraft early conceptual design. The example demonstrates how different options for adequately reformulating optimisation studies are proposed to the designer for further exploration of design alternatives that guarantee the satisfaction of the entire set of constraints.

Set-Based Approach to Passenger Aircraft Family Design

“…Past knowledge and experience is the key in determining domains of the design variables sets. In the case of lack of knowledge, the initial domains of the design variables sets are assigned arbitrarily and therefore other exploration means need to be applied for a more precise definition [114]. The general form of the design variable set V i , ∀i = 1, n v is given by Equation (3.2) where D i is the domain of the ith design variable, and n v is the total number of design variables.…”

“…The analysis involves simulating physical behaviour of the set of aircraft using computational models. The "dynamic workflow creation" method [122] [123] [124] enables the designers to dynamically configure the computational workflows depending on the designers' request for input and output variables, hence providing environment where a large number of aircraft can be analysed quickly.…”

“…but In the next subsection, the proposed methodology for designing passenger aircraft families will be executed for the application case-study. The nomenclature used for the application case-study is listed in [124]. It is important to emphasize that the tools or enablers used in this section are not exclusive.…”

Supporting design via the System Operational Dependency Analysis methodology

“…However, the qualitative considerations on risk and utility are based on classical systems engineering methodology and do not account for some complex features, for example, operational dependencies. Other authors include dependencies between variables in conceptual design (Nunez et al 2012), or in change propagation (Hamraz et al 2012), but only as a qualitative flow, or very simple model of binary or qualitative interdependencies (Augustine et al 2012), or with probabilistic assessments requiring many simulations (Clarkson et al 2004). SODA is a valid alternative to existing parametric models or to simulation-based models.…”

Exploring the Effectiveness of Using Graveyard Data When Generating Design Alternatives

“…Further, design steering provides an environment where the designer (or the human) stays "in-the-loop" throughout the selection process. This is especially important at the earliest stages of design, as designers often work with system models that have imprecision or uncertainty [16][17][18][19][20][21]. Additionally, many models cannot, or do not, model all factors that may impact performance or a designer's overall preference structure for a design [22,23].…”