Functional analysis is a crucial step in engineering that aims to define the functions that each part of a system should perform, without specifying how the design or solution should be implemented. This analysis plays a vital role in translating system-level requirements into detailed functional and performance design criteria. The result of this process is a well-defined functional architecture with allocated system requirements that can be traced to each system function.
Key Facts
- Purpose: Functional analysis aims to define the functions that each part of a system should perform, without specifying how the design or solution should be implemented.
- System Decomposition: Functional analysis involves decomposing a system into lower-level functions that can accomplish the higher-level functional requirements.
- Allocation of Requirements: All requirements of the top-level functions must be allocated to lower-level functions. This ensures traceability and allows system engineers to understand the effects of proposed changes in requirements on related requirements at any system level.
- Functional Architecture: Functional analysis helps in defining an integrated functional architecture that supports the synthesis of solutions in terms of people, products, and processes. It also allows for the identification and management of associated risks.
System Decomposition
Functional analysis involves decomposing a system into lower-level functions that can accomplish the higher-level functional requirements. This decomposition process is iterative, and alternate lower-level functional solutions are proposed and evaluated to determine the best fit to the parent requirements and the optimal balance between conflicting ones. The initial decomposition serves as the starting point for developing the functional architecture and allocating requirements to the lower functional levels. Adjustments to the decomposition strategy may be necessary as details are developed.
Allocation of Requirements
All requirements of the top-level functions must be allocated to lower-level functions. This allocation ensures traceability and allows system engineers to understand the effects of proposed changes in requirements on related requirements at any system level. The allocated requirements must be defined in measurable terms, contain applicable go/no-go criteria, and be in sufficient detail to be used as design criteria in subsequent synthesis activities.
Functional Architecture
Functional analysis helps in defining an integrated functional architecture that supports the synthesis of solutions in terms of people, products, and processes. It also allows for the identification and management of associated risks. The functional architecture and its companion functional requirements serve as inputs to the synthesis activity. Completing the design loop, the detailed results of the synthesis are compared to the candidate architecture(s) and allocated requirements to help determine the optimal approach and ensure that all proposed solutions meet established requirements.
Conclusion
Functional analysis is a critical step in engineering that bridges the gap between high-level system requirements and constraints and the detailed set required to develop or purchase systems and implement programs. It is an iterative process that interacts and reacts to ongoing activities in both the requirements and design loops. By decomposing the system into lower-level functions, allocating requirements, and defining a functional architecture, functional analysis provides a solid foundation for the subsequent synthesis of solutions and the overall success of the engineering project.
References
- Functional Analysis & Allocate Requirements – Wikibooks, open books for an open world
- Functional Analysis and Allocation – AcqNotes
- Functional analysis in systems engineering with IBM Engineering Systems Design Rhapsody
FAQs
What is the purpose of functional analysis in engineering?
- Functional analysis aims to define the functions that each part of a system should perform, without specifying how the design or solution should be implemented.
What is system decomposition in functional analysis?
- System decomposition involves breaking down a system into lower-level functions that can accomplish the higher-level functional requirements.
What is the significance of allocating requirements in functional analysis?
- Allocating requirements ensures traceability and allows engineers to understand the impact of changes in requirements on related requirements at any system level.
What is the role of functional architecture in functional analysis?
- Functional architecture defines an integrated framework that supports the synthesis of solutions and helps identify and manage associated risks.
How does functional analysis contribute to the overall engineering process?
- Functional analysis provides a solid foundation for subsequent synthesis of solutions and contributes to the overall success of the engineering project.
What are some key considerations in defining lower-level functions during functional analysis?
- Alternate lower-level functional solutions should be evaluated to determine the best fit for parent requirements and balance conflicting objectives.
Why is traceability important in functional analysis?
- Traceability allows engineers to track the pedigree of requirements imposed on system and subsystem elements, ensuring a clear understanding of how requirements are derived and allocated.
How does functional analysis interact with other phases of the engineering process?
- Functional analysis is an iterative process that interacts with both the requirements and design loops, ensuring that details are continually validated against each other.