A strategy for modelling the design-development phase of a product

Abstract

This thesis describes a strategy for modelling the design-development phase of a product. Specifically, the aim is to provide product development organisations with a strategy for modelling and optimising sequences and schedules of design-development activities such that this phase of a product's life cycle can be managed and controlled in a more effective manner than before. This helps to ensure that product cost can be minimised, product quality can be maximised and the product's time to market can be reduced. The proposed strategy involves carrying out five strategic functions, namely; (1) create a product design-work breakdown structure of design-development activities; (2) model the activities and their data-dependencies; (3) derive a near optimal sequence of activities; (4) derive an activity network diagram; and, (5) derive a resource-constrained schedule of activities. The five strategic functions involve the use of a number of modelling and optimisation techniques. In particular, the thesis describes; (i) an enhanced version of a matrix-based modelling technique, namely the design structure matrix (DSM), which is used to model design-development activities and their data-dependencies; (ii) a newly created optimisation search procedure which combines a genetic algorithm with a heuristic-based local search to derive a near optimal sequence of activities; (iii) a newly created procedure which, based on the resolution of a matrix-model of activities linked by their mutual dependence on one another for data, is used to derive an activity network diagram of activities and precedence relationships; and, (iv) the development of a multiple-criteria genetic algorithm which is used to derive a near optimal resource-constrained schedule of activities. Near optimal sequences are derived using objectives such as minimising iteration and maximising concurrency whilst near optimal schedules are derived using objectives such as minimising the time taken to complete all activities and maximising the utilisation of scarce resources. At the same time, throughout the thesis, a number of related concepts are discussed and developed. In particular, the thesis addresses concurrent engineering, a systems approach to business processes and design reuse. In order to demonstrate how the modelling strategy can be applied, an industrial case study based on the design-development of a warship has been included.