Product Lifecycle Management (PLM) promises to further a holistic consideration of product design, emphasizing integration, interoperability, and sustainability throughout a product’s lifecycle. Thus far, efforts have focused on addressing lifecycle concerns from a product-centric perspective by exploiting the reusability and scalability of existing products through product platform and product family design. Not much attention has been paid to leveraging the design process and its design in addressing lifecycle considerations, however. In striving for sustainability, it is the design process that should be considered to constitute an engineering enterprise’s primary resource commitment. In this paper, an overview of the challenges inherent in designing design processes is provided. These challenges are subsequently illustrated with regard to several design scenarios of varying complexity, using an example involving the design of Linear Cellular Alloys. A distinction is made between product related requirements/goals and design process related requirements/goals. Requirements, research issues, and strategies for addressing the diverse needs of modeling design processes from a decision-centric perspective are established. Finally, key elements for enabling the integrated design of products and their underlying design processes in a systematic fashion are provided, motivating the extension of PLM to include the lifecycle considerations of design processes, thereby moving towards Design Process Lifecycle Management (DPLM).

Multi-functional design problems are characterized by strong coupling between design variables that are controlled by stakeholders from different disciplines. This coupling necessitates efficient modeling of interactions between multiple designers who want to achieve conflicting objectives but share control over design variables. Various game-theoretic protocols such as cooperative, non-cooperative, and leader/follower have been used to model interactions between designers. Non-cooperative game theory protocols are of particular interest for modeling cooperation in multi-functional design problems. These are the focus of this paper because they more closely reflect the level of information exchange possible in a distributed environment. Two strategies for solving such non-cooperative game theory problems are: a) passing Rational Reaction Sets (RRS) among designers and combining these to find points of intersection and b) exchanging single points in the design space iteratively until the solution converges to a single point. While the first strategy is computationally expensive because it requires each designer to consider all possible outcomes of decisions made by other designers, the second strategy may result in divergence of the solution. In order to overcome these problems, we present an interval-based focalization method for executing decentralized decision-making problems that are common in multi-functional design scenarios. The method involves propagating ranges of design variables and systematically eliminating infeasible portions of the shared design space. This stands in marked contrast to the successive consideration of single points, as emphasized in current multifunctional design methods. The key advantages of the proposed method are: a) targeted reduction of design freedom and b) non-divergence of solutions. The method is illustrated using two sample scenarios — solution of a decision problem with quadratic objectives and the design of multi-functional Linear Cellular Alloys (LCAs). Implications include use of the method to guide design space partitioning and control assignment.

Often, design problems are coupled and their concurrent resolution by interacting stakeholders is required. The ensuing interactions are characterized predominantly by degree of interdependence and level of cooperation. Since tradeoffs, made within and among sub-systems, inherently contribute to system level performance, bridging the associated gaps is crucial. With this in mind, effective collaboration, centered on continued communication, concise coordination, and non-biased achievement of system level objectives, is becoming increasingly important. Thus far, research in distributed and decentralized decision-making has focused primarily on conflict resolution. Game theoretic protocols and negotiation tactics have been used extensively as a means of making the required tradeoffs, often in a manner that emphasizes the maximization of stakeholder (personal) payoff over system level performance. More importantly, virtually all of the currently instantiated mechanisms are based upon the a priori assumption of the existence of solutions that are acceptable to all interacting parties. No explicit consideration has been given thus far to ensuring the convergence of stakeholder design activities leading up to the coupled decision and the associated determination of values for uncoupled and coupled design parameters. Consequently, unnecessary and costly iteration is likely to result from mismatched objectives. In this paper, we advocate moving beyond strategic collaboration towards co-design. We present an alternative coordination mechanism, centered on sharing key pieces of information throughout the process of determining a solution to a coupled system. Specifically, we focus on (1) establishing and assessing collaborative design spaces, (2) identifying and exploring regions of acceptable performance, and (3) preserving stakeholder dominion over design sub-system resolution throughout the duration of a given design process. The fundamental goal is to establish a consistent framework for goal-oriented collaboration that (1) more accurately represents the mechanics underlying product development and (2) facilitates interacting stakeholders in achieving their respective objectives in light of system level priorities. This is accomplished via improved utilization of shared resources and avoidance of unnecessary reductions in design freedom. Comparative performance of the proposed method is established using a simple example, involving the resolution of a tradeoff with respect to a system of non-linear equations.

Different products necessitate different design processes. Determining which such process is most appropriate for a particular product, in turn, requires its delineation before the design of the product under consideration. The phase where design processes are composed is called meta-design. Despite its importance, current simulation-based design frameworks such as FIPER, ModelCenter, and iSIGHT do not support meta-design. This oversight can be attributed at least in part to the fact that these frameworks capture information about products, design processes, and the associated tools in a lumped fashion. Processes are captured in terms of the specific tools employed and the product information, associated with their use, thereby restricting the re-utilization (i.e., reuse via adaptation or customization) of instantiated processes for designing different products. This inherent inability to separate product and process information hinders the exploration of different design process options for designing a product at a fundamental level, thereby restricting meta-design. In order to address this challenge, we propose an approach for distinctly capturing and processing three key components of design related information - a) design problem, b) design process, and c)product. We term this approach, rooted in decision-based design, modularity, and separation of declarative and procedural information, 3-P. The modular separation of information associated with problem, product, and process enables designers to utilize existing knowledge, captured in the form of pre-defined process configurations, for more effectively designing a given product. The proposed approach facilitates the efficient exploration and reconfiguration of design processes, furnishing a much needed and essential basis for meta-design.

In product development, the interfaces between distinct phases of a design process are not well defined and largely misunderstood. The same ambiguity holds true for interactions among distributed stakeholders engaged in shared, concurrent design tasks. Such vagueness fosters poor communication, problematic changeovers, and hard-to-manufacture designs. Resulting design processes tend to be iterative and not only increase product development costs and extend time-to-market, but also ultimately impede collaboration. What is needed is the ability to propagate decision-critical, up-to-date information alongside design knowledge for both sequential and concurrent design tasks. This is particularly important for dependent and interdependent decisions that cannot be made in isolation. To address this need, digital interfaces are being developed as key components to successful collaboration in distributed design and manufacture applications. Such digital interfaces will constitute a means of communicating critical information and will address the need for allocating responsibility for decisions. The potential implementation of a digital interface is illustrated in an example focusing on the production of a functional prototype of a disposable camera spool.