Effective management of product requirements is critical for designers to deliver a quality design solution in a reasonable range of cost and time. The management depends on a well-defined classification and a flexible representation of product requirements. This article proposes two classification criteria in terms of different partitions of product environment based on a formal structure of product requirements. The first criterion classifies the product requirements by partitioning product environment in terms of the product life cycle whereas the second classifies them by partitioning the product environment into natural, built, and human environments. A case study is used to show the feasibility of this approach. This research is the core of a web-based distributed product management system.

In engineering design, customers usually provide product requirements in the form of a natural language while computer-aided design systems may prefer more formal and structured specifications. In this paper, a formalisation process is proposed to transform product requirements from its natural language descriptions to a formal specification. The formal specification is based on the product environment and the formulation of design problem, which identifies the components included in a design problem in terms of the product environment. Through the lexical, syntactic, and structure analysis of natural language descriptions of a design problem, the formalisation process identifies the product to be designed, its environment components, and their relations. A software prototype is developed to validate the formalisation process. An example of rivet setting tool design shows that both the formalisation process and software prototype are feasible.