Product Functional Requirements Research Articles

MITIGATING UNCERTAINTY IN CONCEPTUAL DESIGN USING OPERATIONAL SCENARIO SIMULATIONS: A DATA-DRIVEN EXTENSION OF THE EVOKE APPROACH

AbstractThe paper presents an approach where the iterative replication of Discrete Event Simulations on future operational scenarios is used to derive data-driven design merit functions. The presented contribution proposes an extension of the EVOKE (Early Value Oriented Design Exploration with Knowledge Maturity) approach determining when and how the experience-based judgment about maximization, minimization, optimization, and avoidance functions, correlating value drivers and quantified objectives, can be substituted by data-driven mathematical functions obtained by scenarios simulations. The approach is described through a simplified case concerning the development of autonomous electric vehicles to complement the public transport system in the city of Karlskrona in Sweden. The consideration of value drivers and quantified objectives presented is meant to support a preliminary screening of potential design configurations to support the definition of high-level product and system-related functional requirements, to be run before a more detailed conceptual design analysis.

Multidimensional evaluation method and application based on life cycle carbon efficiency considering carbon emission, cost, and function.

Low carbon research has currently become the most discussed environmental issue. Current comprehensive evaluation methods for low carbon consider carbon emission, cost, process parameters, and resource utilization, but the realization of low carbon may lead to cost fluctuations and functional changes and lack consideration of product functional requirements. Hence, this paper developed a multidimensional evaluation method for low-carbon research based on the association among three dimensions, namely, carbon emission, cost, and function. This multidimensional evaluation method was named life cycle carbon efficiency (LCCE), which is defined as the ratio between the value in the life cycle and the carbon emissions generated. The LCCE model was established, and then carbon emission calculation, cost assessment, and function quantification of the life cycle were performed according to the three dimensions. Case study and sensitivity analysis verified the feasibility of the proposed method. The method had comprehensive and accurate evaluation results, which provided theoretical support and optimized the low-carbon design.

Conduction Transformation-Based Coordination Method for Conflict in Product Adaptive Design Driven by Functional Requirements

A conduction transformation-based coordination method for product structure optimization design was proposed for the conflict between satisfying product functional requirements and realizing adaptive modification. Customer functional requirements were analyzed hierarchically, the extension domains that indicated the matching degree between customer requirement and product function were delimited; and then a multi-layer function-behavior-structure (FBS) mapping model was established. Product function-structure correlation analysis was carried out in two dimensions, i.e., “structure-structure”, and “structure-function”; a product structure behavior function (SBF) reverse conduction model was constructed based on FBS decomposition model; thus, to realize reverse conduction from structure layer to function layer. For conflict coordination in structure modification, extension transformation operations were created, the conduction transformation trigger unit was extracted, and the trigger condition was also clarified; thus, the coordination strategy for the contradiction in adaptive design could be generated by conducting active and conduction transformations. Finally, the effectiveness and feasibility of this method were verified with the structure optimization design of a delivery system of cutting machine as an example; and the discussion section emphasized that this proposed method used conduction transformation to address design conflict, instead of generating the optimal change propagation path, and how to obtain innovation inspiration.

Developing a knowledge-based system for the design of innovative product creation processes for network enterprises

The relevance of developing knowledge-based systems used to support innovative processes for creating products and services is related to the objective need to reduce the life cycle of products under the influence of modern digital technologies in developing network enterprises. Well-known research results in the field of model-oriented design of products, processes, systems and enterprises do not fully provide semantic interoperability in the interaction of stakeholders in the innovation process. The aim of this work is to build a knowledge-based system architecture that implements semantic interoperability of network enterprise participants at various stages of the product lifecycle. The work is based on the use of a model-oriented approach to building a digital thread at all stages of the product lifecycle, an ontological approach to semantic modeling of a distributed knowledge base and a multi-agent approach to organizing interaction between interested participants in the innovation process. The paper proposes a functional architecture of a knowledge-based system that includes modules for planning the innovation process, forming product value characteristics and functional requirements, construction and value chain design. A multi-level system of ontologies of the innovation process is also developed and its application in the work of functional modules that provide access to associated knowledge bases is described. The development of knowledge-based systems based on the results obtained will allow us to find the best design solutions for the configuration of products and corresponding value chains due to the possible iteration of the innovation process and increasing the semantic interoperability of network enterprise stakeholders.

Computational model for generating interactions in conversational recommender system based on product functional requirements

Conversational recommender system is a tool to help customer in deciding products they are going to buy, by conversational mechanism. By this mechanism, the system is able to imitate natural conversation between customer and professional sales support, for eliciting customer preference. However, many customers are not familiar with the technical features of multi-function and multi-feature products. A more natural way to explore customer preferences is by asking what they want to use with the product they are looking for (product functional requirements). Therefore, this paper proposes a computational model incorporating product functional requirements for interaction. The proposed model covers ontology and its structure as well as algorithms for generating interaction that comprises asking question, recommending products and presenting explanation of why a product is recommended. Based on our user studies, both expert users (familiar with product technical features) and novice users (not familiar with product technical feature) prefer our proposed interaction model than that of the flat interaction model (interaction model based on technical features). Meanwhile, functional requirements-based explanation is able to improve user trust in recommended products by 30% for novice users and 17% for expert users.

Analysis Line Approach for Assembly Tolerance Analysis

This work presents the analysis line approach for assembly tolerance analysis. Firstly, the product functional requirements and geometric variations of part positioning features can be converted into small displacements of a series of analysis points along the specified analysis directions. The small displacement torsor (SDT) theory is employed to establish the mathematical relations between the displacements of these analysis points. And then, the variation transfer relations and tolerance accumulation calculations of various orthogonal joints between different parts are studied to determine the maximum displacement of the analysis points on the functional surface. The final displacement accumulation results of the functional surface are compared with the geometric functional requirements of the product, so as to judge whether the product functional requirements are met. Finally, an example is given to demonstrate the effectiveness of the proposed analysis line approach.

Concurrent design and process tolerances determination in consideration of geometrical tolerances

Concurrent design and process tolerances determination may ensure the manufacturability of products, improve the design efficiency, lower the overall production cost, reduce the quantity of unqualified products, and shorten product development cycle. Yet most of the current concurrent tolerancing models focus on the concurrent design of dimensional tolerances without taking into consideration geometrical tolerances. The objective of this study is to extend the concurrent tolerancing model to consider geometrical tolerance requirements. Firstly, the geometrical tolerances are either converted into equivalent dimensional tolerances or only treated as additional machining constraints based on their respective characteristics. Then, a concurrent tolerancing model is established based on ensuring the fulfillment of the product's functional requirements, taking the combination of expected quality loss and manufacturing cost as target function, and taking the functional constraints, geometrical tolerance constraints and process bound constraints as the constraint conditions. After having established the concurrent tolerancing model, the nonlinear programming technique is employed to solve this model to gain the optimal design and process tolerances. Finally, an example of wheel assembly is given to illustrate the validity of the suggested method.

Personalized recommender systems for product-line configuration processes

Product lines are designed to support the reuse of features across multiple products. Features are product functional requirements that are important to stakeholders. In this context, feature models are used to establish a reuse platform and allow the configuration of multiple products through the interactive selection of a valid combination of features. Although there are many specialized configurator tools that aim to provide configuration support, they only assure that all dependencies from selected features are automatically satisfied. However, no support is provided to help decision makers focus on likely relevant configuration options. Consequently, since decision makers are often unsure about their needs, the configuration of large feature models becomes challenging. To improve the efficiency and quality of the product configuration process, we propose a new approach that provides users with a limited set of permitted, necessary and relevant choices. To this end, we adapt six state-of-the-art recommender algorithms to the product line configuration context. We empirically demonstrate the usability of the implemented algorithms in different domain scenarios, based on two real-world datasets of configurations. The results of our evaluation show that recommender algorithms, such as CF-shrinkage, CF-significance weighting, and BRISMF, when applied in the context of product-line configuration can efficiently support decision makers in a most efficient selection of features.

Tolerance Analysis Supports Tolerance Assignment

This work presents a method to support product design, since it shows how to use together tolerance assignment and analysis for choosing among different set of tolerances assigned to the same product. It starts from tolerance assignment that produces different sets of tolerances for the product components which are all acceptable from a functional point of view. It translates each assigned set of tolerances into one or more groups of tolerances that are recognized by the software used for tolerance analysis. Therefore, the software for tolerance analysis is applied to each group of tolerances by means of a Monte Carlo simulation approach. Finally, the obtained results are intersected or compounded to obtain the trend of product functional requirements that allows to identify the best set of tolerances assigned to the product components. The developed method was applied to a skillet, a platform of an industrial plant that is made of five parts connected by screws. The obtained results show how the developed new method is a valid tool to support design for industrial application.

Factors Influencing User’s Adoption of Conversational Recommender System Based on Product Functional Requirements

Conversational recommender system (CRS) helps customers get products fitted their needs by repeated interaction mechanisms. When customers want to buy products having many and high tech features (e.g., cars, smartphones, notebook, etc.), most users are not familiar with product technical features. The more natural way to elicit customers’ needs is by asking what they really want to use with the product they want (we call as product functional requirements). In this paper, we analyze four factors, e.g., perceived usefulness, perceived ease of use, trust and perceived enjoyment associated to user’s intention to adopt the interaction model (in CRS) based on product functional requirements. Result of experiment using technology acceptance model (TAM) indicates that, for users who aren’t familiar with technical features, perceives usefulness is a main factor influencing users’ adoption. Meanwhile, perceived enjoyment plays a role on user’s intention to adopt this interaction model, for users who are familiar with technical features of product.

Design Record Graph and Axiomatic Design for Creative Design Education

The authors have been offering a graduate level design course at the University of Tokyo. The students form groups of about 5 members to identify their own design goals and construct creative solutions to meet the product functional requirements (FRs). The course teaches Design Record Graph (DRG), a network diagram that starts with the product FR that divides into a number of sub-functions. The division continues until all functional elements are identified, and when every element functional requirement maps to a single element design parameter (DP), the design meets the independence axiom. The projects often start with heavily coupled designs that gradually turn into clean solutions towards their finalized design. The graph expression is easier for design students to get started with functional decomposition without having to work with design matrices.

A Concurrent Approach to Reducing Environmental Impact of Product Development at the System Design Stage

This paper presents a computational framework for reducing environmental impact of product development in consideration of product design, manufacturing, and the supply chain concurrently. This framework incorporates a number of factors that ecologically influence the product lifecycle activities into product architecture design. They allow a systematic variation of manufacturing bill of materials. CAD-based functions are developed to ensure that the variation results satisfy product functional requirements and are interference-free during assembly. A cradle-to-gate lifecycle assessment is conducted on the bill of materials. Optimization schemes are integrated with the variation process to search for optimal results. This work realizes sustainable product development by offering a tool of ecological decision making in the system design stage.

Relating additive and subtractive processes in a teleological and modular approach

PurposeThe purpose of this paper is to relate additive manufacturing (AM) and machining (CNC) synergistically in a modular approach in the design and manufacturing domains, to generate value for end‐users and manufacturers (a teleological system).Design/methodology/approachThe research methodology decomposes a part into modules, by employing a teleological systems theory approach paired with principles of modular design. Modules are manufactured with either additive manufacturing (fused deposition modeling, FDM) or machining (CNC). Process selection is determined by a decision‐making framework that quantifies strength and weakness comparisons of FDM and CNC machining processes, accomplished using the analytic hierarchy process (AHP).FindingsThe developed methodology and decision‐making framework is successfully applied to the design and manufacturing of a large, complex V6 engine section sand casting pattern. This case study highlights the merits of the research.Research limitations/implicationsThe research assumes that the processes being considered are capable of meeting the product functional requirements. The proposed methodology can be extended to evaluate additional processes.Practical implicationsValue is assessed in this research relative to: time and cost opportunities, managing knowledge limitations of a process by leveraging hybrid options, and aligning design and manufacturing to create a product that accomplishes the goals of the end‐user (teleological effectiveness).Originality/valueUtilizing the AHP process and a teleological perspective are new, and proven effective, approaches in relating additive and subtractive processes in a hybrid approach with end‐user perspectives. The research demonstrates a systematic methodology to quantify additive and subtractive process selection.

Model-driven approach to developing domain functional requirements in software product lines

Existing product requirements form a rich source for domain requirements analysis in software product lines (SPLs). Most existing domain analysis techniques depend on domain experts’ experience and manual operation to identify the commonalities and variabilities of product requirements. They often demand a high level of manual effort and a large up-front investment, which can present a prohibitive barrier for SPL adoption. This study proposes a model-driven approach to semi-automatically derive domain functional requirements (DFRs) from product functional requirements (PFRs). Based on the linguistic characterisation of a domain's action-oriented concerns, the authors apply Fillmore's semantic framework to functional requirements and define metamodels for PFRs and DFRs. Functional requirements of existing products are constructed as corresponding PFR models. Following the proposed merging and refinement rules, the authors approach automates the transformation from PFR models into DFR models by merging the same or similar PFRs and analysing their commonality and variability. The resulting DFR models can serve as an initial basis of the SPL. The authors demonstrate the authors approach using an example of a home security system (HSS) SPL and give a preliminary evaluation. The authors approach provides a rigorous model-based support for DFRs development and complements existing domain analysis techniques with less time and effort.

Research on Operational Model of New-Generation GPS Based on Dynamic Description Logic

Operation and Operator are the key technologies in the new-generation geometrical product specification and verification (GPS). In order to solve the geometrical specification problems of product functional requirements and the ambiguity problems of product specification, this paper utilizes a new method based on dynamic description logic to describe the fundamental concepts of geometrical specification. It analyzes the geometrical features of geometrical product functional specification. By establishing the model of the operations, describing the input and output parameters in the specification and verification process, and analyzing the preconditions and results of the executions of specification operator and verification operator, the paper simplifies the operation results and overcomes the shortcomings of ambiguity and inconsistency in product specification process. Finally, it takes the specification process of perpendicularity as an example to prove the feasibility and validity of this method.

3.2.1 Proposal of method to estimate of the probability to fulfillment product's functional requirements

AbstractThis work proposes a method to estimate the probability of meeting functional requirements of complex products. The method uses concepts and techniques from Systems Engineering and from Reliability. Functional interactions represented in the Functional Flow Block Diagrams (FFBD) are translated into a correspondent configuration of the reliability block diagram (RBD), according to the method's conventions. After that, a reliability value is attributed to each component block, and using reliability evaluation methods the probability of meeting a particular functional requirement is estimated. An application example is presented by missile's subsystem.

Tolerance allocation for compliant beam structure assemblies

This paper presents a tolerance allocation methodology for compliant beam structures in automotive and aerospace assembly processes. The compliant beam structure model of the product does not require detailed knowledge of product geometry and thus can be applied during the early design phase to develop cost-effective product specifications. The proposed method minimizes manufacturing costs associated with tolerances of product functional requirements (key product characteristics, KPCs) under the constraint(s) of satisfying process requirements (key control characteristics, KCCs). Misalignment and fabrication error of compliant parts, two critical causes of product dimensional variation, are discussed and considered in the model. The proposed methodology is developed for stochastic and deterministic interpretations of optimally allocated manufacturing tolerances. An optimization procedure for the proposed tolerance allocation method is developed using projection theory to considerably simplify the solution. The non-linear constraints, that ellipsoid defined by (stochastic case) or rectangle defined by T x (deterministic case) lie within the KCC region, are transformed into a set of constraints that are linear in σ (or T x )-coordinates. Experimental results verify the proposed tolerance allocation method.

Simultaneous optimal selection of design and manufacturing tolerances with different stack-up conditions using genetic algorithms

Tolerance design is one of the most critical aspects of product design and development process as it affects both the product's functional requirements and manufacturing cost. Unnecessarily tight tolerances lead to increased manufacturing cost, while loose tolerances may lead to malfunctioning of the product. Traditionally, this important phase of product development is accomplished intuitively to satisfy design constraints, based on handbooks' data and/or skill and experience of the designers. Tolerance design carried out in this manner does not necessarily lead to an optimum design. Research in this area indicates that, in general, tolerance design is carried out sequentially in two steps; (1) tolerance design in CAD to obtain design or functional tolerances and (2) tolerance design in CAPP to obtain manufacturing tolerances. Such a sequential approach to tolerance design suffers from several drawbacks, such as more time consumption, suboptimality and unhealthy working atmosphere. This paper reports on an integrated approach for simultaneous selection of design and manufacturing tolerances based on the minimization of the total manufacturing cost. The nonlinear multivariable optimization problem formulated in this manner may result in a noisy solution surface, which can effectively be solved with the help of a global optimization technique. A solution methodology using genetic algorithms and applying penalty function approach with proper normalization of the penalty terms for handling the constraints is proposed. The application of the proposed methodology is demonstrated on a simple mechanical assembly with different tolerance stack-up conditions.

Requirements management: a representation scheme for product specifications

Product definition processes take a product specification (defining the requirements that the product must satisfy) and transform it into a product definition (defining, at least, the shape and material of the required product so that it can be manufactured). Recent advances in computer aided design technology have allowed product definitions to be captured electronically. Currently the resulting electronic product definitions are centred around representations of physical product structures and shape-related properties. The industrial need is now moving towards a desire to manage requirements in a plausible architecture. From this basis the product's functional requirements can be identified and converted into physical elements which can be related to design intent/rationale; this requires the linking of elements of physical product structure and shape with elements of an electronic product specification. The research reported in this paper is focussed on the realisation of an electronic product specification. Such a specification must be defined in a way that allows relationships to electronic product definitions to be established. A product data model that supports the description of mechanical product specifications is presented and its functionality is demonstrated through a case study.

A Systems Engineering Environment For Integrated Automotive Powertrain Development

Automotive powertrain control system (PCS) development faces tightening environmental requirements, shortening development cycle times and growing complexity. To cope with such an environment, PCS development is moving from a traditional evolutionary to a structured approach. The structured approach is supported by computerised structured analysis methods. However, these methods concentrate on the functional and interface requirements of the product. This paper aims to describe how a systems engineering environment (SEE) can be used for integrated PCS development by addressing not only product functional and interface requirements but also life cycle process and organisational requirements. The particular SEE used, a commercial software package, provides: · notations from different modelling paradigms, used for integrated functional, product, process and organisational modelling; · cross-references, used to link functional, product and life-cycle processes attributes; · frames to capture further information about each data items (e.g. CAD drawings). A major benefit of the application of the SEE for an integrated PCS development is the ability to investigate early in the product development/evolution process the interactions between requirements and attributes not only of the product but also of its life cycle processes and development organisation. It is demonstrated how an SEE can be used to provide better product quality, lower life cycle cost and shorter development time. The application of a systems engineering approach to a product, its life cycle processes and its development organisation in an integrated manner encompasses concurrent engineering. It provides a much broader scope for product development, in this case, the PCS subsystem.