Towards Rules for Functional Composition

2008 ◽  
Author(s):  
Benjamin W. Caldwell ◽  
Gregory M. Mocko
Keyword(s):  
Conceptual Design ◽  
Functional Model ◽  
Functional Composition ◽  
Functional Decomposition ◽  
Functional Basis ◽  
Functional Models ◽  
Hierarchical Levels ◽  
Unknown Solution

Functional decomposition is used in conceptual design to divide an overall problem with an unknown solution into smaller problems with known solutions. The procedure for functional decomposition, however, has not been formalized. In a larger effort to understand and develop rules for functional decomposition, this paper develops rules for composition of reverse-engineered functional models. First, the functional basis hierarchy is used in an attempt to compose the functional model of a hair dryer, which does not produce the desired results. Second, a set of rules for composition is presented and applied to the hair dryer functional model. This composed functional model is more similar to the desired decomposition result than the functional model developed by changing hierarchical levels. Ten additional functional models are also composed and the results shown. The findings demonstrate that composition rules can be developed empirically through analysis of functional models.

A Theory for the Development of Conceptual Functional Models for Automation of Manual Processes

2007 ◽  
Author(s):  
Robert L. Nagel ◽  
Robert B. Stone ◽  
Daniel A. McAdams
Keyword(s):  
Conceptual Design ◽  
Functional Model ◽  
Process Models ◽  
Functional Modeling ◽  
Functional Basis ◽  
Functional Models ◽  
Electromechanical Products ◽  
The Creation

Conceptual design is a vital stage in the development of any product, and its importance only increases with the complexity of a design. Functional modeling with the Functional Basis provides a framework for the conceptual design of electromechanical products. This framework is just as applicable to the conceptual design of automated solutions where an engineered product with components spanning multiple engineering domains is designed to replace or aid a human and his or her tools in a human-centric process. This paper presents research toward the simplification of the generation of conceptual functional models for automation solutions. The presented methodology involves the creation of functional and process models to fully explore existing human operated tasks for potential automation. Generated functional and process models are strategically combined to create a new conceptual functional model for an automation solution to potentially automate the human-centric task. The presented methodology is applied to the generation of a functional model for a conceptual automation solution. Then conceptual automation solutions generated through the presented methodology are compared to existing automation solutions to demonstrate the effectiveness of the presented methodology.

Development of a Functional Basis for Design

1999 ◽  
Author(s):  
Robert B. Stone ◽  
Kristin L. Wood
Keyword(s):  
Classification Scheme ◽  
Mechanical Design ◽  
Functional Model ◽  
Coding System ◽  
Structure Generation ◽  
Functional Basis ◽  
Product Function ◽  
Functional Models ◽  
Functional Representations ◽  
Architecture Development

Abstract Functional models represent a form independent blueprint of a product. As with any blueprint or schematic, a consistent language or coding system is required to ensure others can read it. This paper introduces such a design language, called a functional basis, where product function is characterized in a verb-object (function-flow) format. The set of functions and flows is intended to comprehensively describe the mechanical design space. Clear definitions are provided for each function and flow. The functional basis is compared to previous functional representations and is shown to subsume these attempts as well as offer a more consistent classification scheme. An example is provided for using the functional basis to form a functional model. Applications to the areas of product architecture development, function structure generation, and design information archival and transmittal are discussed.

Toward a Generative Human-in-the-Loop Approach for Conceptual Design Exploration Using Flow Failure Frequency in Functional Models

2018 ◽  
Author(s):  
Ryan M. Arlitt ◽  
Douglas L. Van Bossuyt
Keyword(s):  
Risk Assessment ◽  
Conceptual Design ◽  
Electrical Power ◽  
Functional Model ◽  
Flow Distribution ◽  
Heat Extraction ◽  
System Failure ◽  
Electrical Power System ◽  
Human In The Loop ◽  
Functional Models

A challenge systems engineers and designers face when applying system failure risk assessment methods such as Probabilistic Risk Assessment (PRA) during conceptual design is their reliance on historical data and behavioral models. This paper presents a framework for exploring a space of functional models using graph rewriting rules and a qualitative failure simulation framework that presents information in an intuitive manner for human-in-the-loop decision-making and human-guided design. An example is presented wherein a functional model of an electrical power system is iteratively perturbed to generate alternatives. The alternative functional models suggest different approaches to mitigating an emergent system failure vulnerability in the electrical power system’s the heat extraction capability. A preferred functional model configuration that has a desirable failure flow distribution can then be identified. The method presented here helps systems designers to better understand where failures propagate through systems and guides modification of systems functional models to adjust the way in which systems fail to have more desirable characteristics.

A Semantic Framework to Integrate Healthcare and Clinical Knowledge in Medical Device Innovation and Design

2014 ◽  
Author(s):  
Thomas J. Hagedorn ◽  
Ian R. Grosse ◽  
Sundar Krishnamurty ◽  
Jack C. Wileden
Keyword(s):  
Engineering Design ◽  
Medical Device ◽  
Functional Model ◽  
Medical Knowledge ◽  
Medical Procedure ◽  
Clinical Knowledge ◽  
Functional Basis ◽  
Functional Models ◽  
Effective Transfer ◽  
Early Phases

Within the medical field, there has been significant progress in the development of ontologies and their subsequent use to represent and utilize knowledge more effectively. These have culminated in the creation of large, curated medical ontologies for use in a wide array of applications, as well as higher level frameworks to organize and mitigate conflicts between disparate ontologies. While the engineering field has not been a similar progress in developing and adopting curated ontologies, there has been extensive research into how to effectively use semantic frameworks in engineering knowledge management and design in general, and specifically for the effective creation and documentation of functional basis models. Functional models are a useful tool in the early phases of product design, as they can help more effectively define goals and represent how a product must behave to accomplish these goals. In the specific realm of medical device design however, this process is complicated by a number of factors, including the complexity of the healthcare system and clinical knowledge, as well as a lack of domain specific expertise in the engineering field. Because of these challenges, effective transfer of information from medical domain experts to an engineering context and subsequent utilization of this information are essential to the success of a medical device innovation project. Despite the magnitude and importance of this challenge, few tools exist to help designers record, contextualize, and utilize medical knowledge for the specific purpose of engineering design. In this paper, we present a framework for directly integrating clinical knowledge relating to medical science and practice into the early phases of the engineering process to assist in medical device innovation and design. To accomplish this, existing medical and engineering ontologies were researched, obtained, and interlinked so as to explicitly tie functional models of medical device designs to the underlying medical clinical knowledge and procedures that define a product’s operational environment. The result is a framework that unifies the knowledge embodied in large medical ontologies with the functional basis ontology. This integration facilitates the effective preservation and use of medical knowledge in functional model creation and in the engineering design innovation process in general. To demonstrate the potential usefulness of this framework, we present a simple example of how our framework can be used to associate a functional model with a deconstructed medical procedure, thus enabling the seamless integration of a medical perspective directly into an engineering model.

A Model-Based Functional Modeling and Library Approach for Mechatronic Systems in SysML

2012 ◽  
Author(s):  
Benjamin Kruse ◽  
Clemens Münzer ◽  
Stefan Wölkl ◽  
Arquimedes Canedo ◽  
Kristina Shea
Keyword(s):  
Functional Model ◽  
Mechatronic Systems ◽  
Component Structure ◽  
Functional Basis ◽  
Model Based ◽  
Modeling Approach ◽  
Electric Car ◽  
Functional Models ◽  
Computer Based ◽  
Early Phases

Even though the concept development phase in product development is arguably the most important phase in mechanical and mechatronics design, the available computer-based support for this stage is marginal. This paper presents a new computational model-based method to improve the early phases of mechatronic product design and to facilitate the application from early designs to detailed designs. The paper focuses on model-based Function-Behavior-Structure (FBS) libraries in SysML to support both the manual and computational generation of standard and innovative concepts. In this paper, an approach to re-usable functional models in SysML is presented. The method uses an operator-flow formulation of functions, based on the NIST functional basis, and is validated against a model of an electric car. The generated functional models are validated with respect to the consistency of the flows and tested by associating the functional model directly to the target product component structure. The results of the research are a new modeling approach for function and component libraries in SysML, an associated workflow for modeling of mechatronic systems, and the necessary extensions of the NIST functional basis. The modeling approach provides means for formal functional decomposition followed by an allocation of the functions to structural components that form the target structure.

A Generative Human-in-the-Loop Approach for Conceptual Design Exploration Using Flow Failure Frequency in Functional Models1

2019 ◽  
Vol 19 (3) ◽  
Author(s):  
Ryan M. Arlitt ◽  
Douglas L. Van Bossuyt
Keyword(s):  
Risk Assessment ◽  
Conceptual Design ◽  
Electrical Power ◽  
Functional Model ◽  
Flow Distribution ◽  
Heat Extraction ◽  
System Failure ◽  
Electrical Power System ◽  
Human In The Loop ◽  
Functional Models

A challenge systems engineers and designers face when applying system failure risk assessment methods such as probabilistic risk assessment (PRA) during conceptual design is their reliance on historical data and behavioral models. This paper presents a framework for exploring a space of functional models using graph rewriting rules and a qualitative failure simulation framework that presents information in an intuitive manner for human-in-the-loop decision-making and human-guided design. An example is presented wherein a functional model of an electrical power system testbed is iteratively perturbed to generate alternatives. The alternative functional models suggest different approaches to mitigating an emergent system failure vulnerability in the electrical power system's heat extraction capability. A preferred functional model configuration that has a desirable failure flow distribution can then be identified. The method presented here helps systems designers to better understand where failures propagate through systems and guides modification of systems functional models to adjust the way in which systems fail to have more desirable characteristics.

scholarly journals Supporting resilient conceptual design using functional decomposition and conflict resolution

2021 ◽  
Vol 48 ◽  
pp. 101262
Author(s):  
Xin Guo ◽  
Ying Liu ◽  
Wu Zhao ◽  
Jie Wang ◽  
Ling Chen
Keyword(s):  
Conflict Resolution ◽  
Conceptual Design ◽  
Functional Decomposition

Applying Function-Based Failure Propagation in Conceptual Design

2007 ◽  
Author(s):  
Daniel Krus ◽  
Katie Grantham Lough
Keyword(s):  
Risk Analysis ◽  
Product Design ◽  
Conceptual Design ◽  
Functional Model ◽  
Thermal Control ◽  
Design Phase ◽  
Historical Knowledge ◽  
Conceptual Design Phase ◽  
Failure Propagation ◽  
Potential Risks

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.

Functional Models With Inherent Behavior: Towards a Framework for Safety Analysis Early in the Design of Complex Systems

2016 ◽  
Author(s):  
Matthew G. McIntire ◽  
Elham Keshavarzi ◽  
Irem Y. Tumer ◽  
Christopher Hoyle
Keyword(s):  
Design Process ◽  
Functional Model ◽  
Behavioral Model ◽  
Safety Analysis ◽  
State Machine ◽  
System Component ◽  
State Transitions ◽  
Failure Behavior ◽  
State Machines ◽  
Functional Models

This paper represents a step toward a more complete frame-work of safety analysis early in the design process, specifically during functional modeling. This would be especially useful when designing in a new domain, where many functions have yet to be solved, or for a problem where the functional architecture space is large. In order to effectively analyze the inherent safety of a design only described by its functions and flows, we require some way to simulate it. As an already-available function failure reasoning tool, Function Failure Identification and Propagation (FFIP) utilizes two distinct system models: a behavioral model, and a functional model. The behavioral model simulates system component behavior, and FFIP maps specific component behaviors to functions in the functional model. We have created a new function-failure reasoning method which generalizes failure behavior directly to functions, by which the engineer can create functional models to simulate the functional failure propagations a system may experience early in the design process without a separate behavioral model. We give each basis-defined function-flow element a pre-defined behavior consisting of nominal and failure operational modes, and the resultant effect each mode has on its functions connected flows. Flows are represented by a two-variable object reminiscent of a bond from bond graphs: the state of each flow is represented by an effort variable and a flow-rate variable. The functional model may be thought of as a bond graph where each functional element is a state machine. Users can quickly describe functional models with consistent behavior by constructing their models as Python NetworkX graph objects, so that they may quickly model multiple functional architectures of their proposed system. We are implementing the method in Python to be used in conjunction with other function-failure analysis tools. We also introduce a new method for the inclusion of time in a state machine model, so that dynamic systems may be modeled as fast-evaluating state machines. State machines have no inherent representation of time, while physics-based models simulate along repetitive time steps. We use a more middle-ground pseudo time approach. State transitions may impose a time delay once all of their connected flow conditions are met. Once the entire system model has reached steady state in a timeless sense, the clock is advanced all at once to the first time at which a reported delay is ended. Simulation then resumes in the timeless sense. We seek to demonstrate this modeling method on an electrical power system functional model used in previous FFIP studies, in order to compare the failure scenario results of an exhaustive fault combination experiment with similar results using the FFIP method.

A Mathematical Functional Decomposition Approach Through Granularity Partition Process in Quotient Space

2018 ◽  
Author(s):  
Y. T. Li ◽  
Y. X. Wang
Keyword(s):  
Conceptual Design ◽  
Quotient Space ◽  
Lower Layer ◽  
Solution Space ◽  
Decomposition Process ◽  
Decomposition Approach ◽  
Functional Decomposition ◽  
Topological Structures ◽  
Functional Reasoning ◽  
Partition Process

Over the past decades, several methodologies have coalesced around the functional decomposition and partial solution manipulation techniques. These methodologies take designers through steps that help decompose a design problem and build conceptual solutions based on the intended, product functionality. However, this kind of subjective decomposition restricts solutions of conceptual design within designers’ intended the local, rather the whole, solution space. In such cases, the ability for AI-based functional reasoning systems to obtain creative conceptual design solutions is weakened. In this paper, a functional decomposition model based on the domain decomposition theory in quotient space is proposed for carrying out functional decomposition without needing functional reasoning knowledge to support. In this model, the functional decomposition is treated as a granularity partition process in quotient space composed of three variables: the domain granularities, the attribute properties, and the topological structures. The closeness degrees and the attribute properties in fuzzy mathematics are utilized to describe the fuzzy equivalence relations between the granularities in the up-layer and in the lower-layer of the functional hierarchies. According to the order characteristics in the partially sequential quotient space, based on the homomorphism principle, the attribute properties and the topological structures corresponding to the lower-layer of the functional hierarchies are constructed then. Here, the attribute properties are expressed with membership functions pointed to the lower-layer from the up-layer of the functional hierarchies, and the topological structures are expressed with matrixes and the directed function network represent the topological connections among the subfunctions in the lower-layer of the functional hierarchies. Through refining the functional decomposition process step by step, and traversing all tree branches and leaf nodes in the functional decomposition tree, the functional hierarchies are obtained. Since the functional decomposition process not need the user to indicate or manage desired functionality, the model presented in this paper can reduce designers’ prejudices or preconceptions on the functional hierarchies, as well as extend the solution space of conceptual design.

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