The impact of a design change in an engineering development environment: A case study

The aim of this paper is to identify and analyze the impact of a design change in a concurrent systems engineering environment. A mathematical model has been developed to quantify the impact of a design change on a multi-layer, multi-component system. This model confirms that the system hierarchy design is very important to minimize the impact and subsequent development project risk should a design change be required for one of the system components. The mathematical model shows that a design change often has a detrimental effect on project cost and schedule due to the ripple effect of forced design changes to all other functionally coupled system elements. In practice, design modifications/changes particularly during system integration of a complex multi-hierarchical system are virtually unavoidable. The impact of forced changes can only be improved by optimizing the system architecture to keep the system data content or functional couplings to a minimum. The actual impact of a design change in a real system under development can by means of the model be calculated in order to assess the feasibility of allowing the design change or to rather look for alternative lesser development project intrusive solutions to the problem at hand. The model shows that early system engineering to optimize the system architecture with the objective of reducing the system information content is beneficial. This will reduce development project risk as result of unexpected forced design changes in a concurrent engineering development environment. The paper shows that in order to reduce system development project risk, it is important to minimise the system data content (functional couplings) and mature each system element design before integration.