Risk assessments are necessary to anticipate and prevent accidents from occurring or repeating. Current probabilistic risk assessment methods require mature design proposals to analyse. Since product safety and reliability are affected the most by decisions made during the early design phases, a risk assessment that can be performed with less mature data during these design phases is needed. This study focuses specifically on the relationship between function and risk in early design by presenting a mathematical mapping from product function to risk assessments that can be used in the conceptual design phase. An investigation of a spacecraft orientation subsystem is used to demonstrate the mappings. The results from the study and its spacecraft application yield a preliminary risk assessment method that can be used to identify and assess risks as early as the conceptual phase of design. The preliminary risk assessment presented in this paper is a tool that will aid designers by identifying risks as well as reducing the subjectivity of the likelihood and consequence value from a risk element, will provide four key risk element properties (design parameter, failure mode, likelihood, and consequence) for numerous risk elements with simple calculations, and will provide a means for inexperienced designers to effectively address risk in the conceptual design phase.

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Risk assessments are necessary to anticipate and prevent accidents from occurring or repeating. This paper focuses specifically on the relationship between function and risk by presenting a mathematical mapping from product function to risk likelihood. This type of mapping will aid designers by removing the subjectivity of the likelihood value from a risk element, provide three key risk element properties (design parameter, failure mode, and likelihood) for numerous risk elements with one simple mathematical calculation, and provide a means for inexperienced designers to effectively address risk in the conceptual design phase. In addition, the level of detail a functional model should be written in to produce adequate likelihood risk assessments is examined. Three case studies are used to validate the proposed mapping: A spacecraft orientation subsystem, a subsystem to guide science instruments on an extraterrestrial, and subsystems from a Bell 206 rotorcraft. The work described in this paper continues is part of ongoing research relating function to failure.

When designing a product, the earlier the potential risks can be identified, the more costs can be saved, as it is easier to modify a design in its early stages. Several methods exist to analyze the risk in a system, but all require a mature design. However, by applying the concept of "common interfaces" to a functional model and utilizing a historical knowledge base, it is possible to analyze chains of failures during the conceptual phase of product design. This paper presents a method based on these common interfaces to be used in conjunction with other methods such as risk in early design to allow a more complete risk analysis during the conceptual design phase. Finally, application of this method is demonstrated in a design setting by applying it to a thermal control subsystem.

When designing a product, the earlier the potential risks can be identified, the more costs can be saved, as it is easier to modify a design in its early stages. Several methods exist to analyze the risk in a system, but all require a mature design. However, by applying the concept of “common interfaces” to a functional model and utilizing a historical knowledge base, it is possible to analyze chains of failures during the conceptual phase of product design. This paper presents a method based on these “common interfaces” to be used in conjunction with other methods such as Risk in Early Design in order to allow a more complete risk analysis during the conceptual design phase. Finally, application of this method is demonstrated in a design setting by applying it to a thermal control subsystem.