Product families are frequently used to provide consumers with a variety of appealing products and to help maintain reasonably low production costs for manufacturers. Three common objectives in the design of product families are used to balance the interests of both consumers and manufacturers. These objectives are to maximize (i) product performance, (ii) product distinctiveness as perceived by the consumer, and (iii) product commonality as seen by the manufacturer. In this thesis, three methods are introduced that use multiobjective optimization and Smart Pareto filtering to satisfy the three objectives of product family design. The methods are progressive in nature and begin with the selection of product family members using Smart filtering and develop through the establishment of scale- based product platforms to the design of combined scale- based and module-based product platforms. Each of the methods is demonstrated using a well-know universal electric motor example problem. The results of each method are then compared to a benchmark electric motor product family that was previously defined in the literature. Additionally, a pressure vessel example problem is used to further demonstrate the first of the three methods.

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In software product line engineering, the construction of an architecture for a product family is still an outstanding engineering challenge. In current practice, a framework is used for configuring individual products by combining solution space artefacts into products with specified features according to a feature model. No architectures are created. In contrast, an architecture for a product family would define the architectures for all the products in the family, allowing engineers to reason at a higher level of abstraction. In this thesis, we present a component model that can be used to define architectures for product families, by incorporating explicit variation points.

<p>Some products share one or two modules and while developing these products, structural optimization with stiffness as the objective function can be a useful tool. There might be no or very little CAD-data available in the pre-development phase and it is not certain that existing designs can be, or is desirable to use as a reference. The main objective of this thesis is to establish an accurate and fast-to-use methodology which can be utilized while developing new cars.</p><p>In this thesis, the Volvo products S40, V50 and C70 serve as a basis for this case study. All the models are beam structures and the masses of components are added as point and line masses. Several optimization analyses are performed on one or three products exposed to seven load cases. Additional analyses with shell elements, more simplified models and changed load case balance achieved by normalization of the different load case compliances are also studied to investigate how these factors influence the results.</p><p>Analyses show that front crash to a great extent dominates the results while normalization increases the influence of the remaining load cases. Since front crash is dominating and the front area is shared in all products, the performance is remarkably similar when three products are optimized compared to separate analyses of one product. Analysis of models without added point or line masses gives a result which greatly differs from previous results and therefore shows that added masses are required. The methodology is applicable to develop products and detect new load paths through the car.</p>

Some products share one or two modules and while developing these products, structural optimization with stiffness as the objective function can be a useful tool. There might be no or very little CAD-data available in the pre-development phase and it is not certain that existing designs can be, or is desirable to use as a reference. The main objective of this thesis is to establish an accurate and fast-to-use methodology which can be utilized while developing new cars. In this thesis, the Volvo products S40, V50 and C70 serve as a basis for this case study. All the models are beam structures and the masses of components are added as point and line masses. Several optimization analyses are performed on one or three products exposed to seven load cases. Additional analyses with shell elements, more simplified models and changed load case balance achieved by normalization of the different load case compliances are also studied to investigate how these factors influence the results. Analyses show that front crash to a great extent dominates the results while normalization increases the influence of the remaining load cases. Since front crash is dominating and the front area is shared in all products, the performance is remarkably similar when three products are optimized compared to separate analyses of one product. Analysis of models without added point or line masses gives a result which greatly differs from previous results and therefore shows that added masses are required. The methodology is applicable to develop products and detect new load paths through the car.

The recent trend of mass customization has redefined the way companies do business. Each individual customer is now their own market, requiring products specific to their wants and needs at mass production prices. This need for ever-increasing variety is a significant challenge for industry that many times leads to ballooning manufacturing costs and lower product performance. One approach that has received widespread attention and implementation is to develop families of products from standardized product platforms. While, many methods have been developed to address different challenges within product platform design, they are not without their limitations/tradeoffs and therefore leave much room for development and improvement. The Product Platform Constructal Theory Method (PPCTM), developed by Dr. Gabriel Hernandez, is a novel approach for developing product platforms that enable customizable products. Rooted in the tenants of hierarchic systems theory and constructal theory, the PPCTM solves for the product platform as a problem of optimization of access in a geometric space. The result is a hierarchical organization of the modes for managing variety and the specification of their commonality across the product platform. Overall, the PPCTM offers an extremely comprehensive product platform design method, with the ability to accommodate multi-platform design, multiple design specifications, non-uniform demand modeling, and multi-objective decision-making. One limitation of this method is that the selection of platform variables and the modes for managing product variety must be pre-specified or determined ad hoc by the designer. This thesis seeks to address this limitation through the integration of a sensitivity-based analysis method to determine the effect of platform variable variation on the family performance. The result of this work is a Sensitivity-based PPCTM that facilitates the selection of common platform variables, such that modes for managing variety can be ranked and applied to the space element hierarchy. The proposed method is illustrated with three examples: the design of a line of customizable pressure vessels, universal electric motors, and finger pumps.

Engineered to Order (ETO) products can benefit from the concepts and tools offered by Product and Platforms Line Engineering (PLE) (such as increased variety offer and efficient use of resources), and CAD/PLM (Computer Aided Design/Product Life-cycle management) in order to gain competitiveness. This paper portrays a framework for describing and measuring the processes that conform that connection between PLE and CAD; presents a description of the key components of the entire process, their relationships, as well a set of metrics for assessing the ability of a process for creating Geometrical CAD Platforms. A case study of an ETO product development with the implementation of this framework is presented in two different scenarios for validating the concepts exposed and demonstrating the use of the framework for assessing the capability of an organization for creating 3DCAD platforms for ETO Products.

<p>The set of related products is referred to as a product family, and feature-modeling is a widely used technique to capture the commonalities and variabilities of a product family in terms of "features". With the growing complexity of software product families in several software industries, the development, maintenance and evolution of complex and large feature models are among the main challenges faced by feature-modeling practitioners. In particular, more sophisticated feature-modeling techniques are required to address the problems caused by unanticipated changes and crosscutting concerns in feature models.</p> <p>This thesis tackles the above challenges in feature-modeling by adopting the aspect-oriented paradigm at the feature-modeling level. I first introduce a specification language, called AO-PFA, which is an extension of the Product Family Algebra (PFA) language. I then proposed a formal verification technique to check the compatibility of aspects with their base specifications in AO-PFA. In the aspect-oriented paradigm, the process of combining aspects with base specifications is referred to as the weaving process. I finally discussed how to perform the weaving process in AO-PFA. By proposing a systematic approach to extend product family algebra with the abilities of specifying, verifying, and weaving aspects, we are able to handle the difficulties that arise from crosscutting concerns and unanticipated changes in large-scale feature models.</p> / Doctor of Philosophy (PhD)

In today's market, companies are faced with pressure to increase variety in product offerings. While increasing variety can help increase market share and sales growth, the costs of doing so can be significant. Ultimately, variety causes complexity in products and processes to soar, which negatively impacts product development, quality, production scheduling, efficiency and more. Product variety is just one common cause of product complexity, a topic that several researchers have tackled with several sources of product complexity now identified. However, even with such progress, product complexity continues to be a theoretical concept, making it difficult for companies to fully implement advances and fully manage product complexity. More and more companies are relying on product family design to handle product variety. Broadly, a product family can be defined as a group of products sharing common elements. The advantages for companies using product family strategies can be significant: they enable efficient derivation of product variants, reduce inventory and handling costs, as well as setup and retooling time. The design challenge however, is to select the product platform to generate a variety of products with minimum deviation from individual requirements. Accordingly, the structure of product families makes designing and evaluating them a challenging process. In order to fully embrace the relationships between variety, product complexity, and product families an understanding of product complexity causes and impacts is essential. This research begins by introducing four main dimensions of product complexity within the context of a generalized definition. Product complexity indicators suitable in product design, development and production are derived. By establishing measurements for the identified indicators and using clustering techniques, a complexity evaluation approach for product family designs is also developed in this research. The evaluation approach is also applied on a component basis, to identify Critical Components that are main sources and contributors of complexity within product families. By standardizing identified Critical Components, product complexity levels and associated costs can be managed. A case application of three product families from a tire manufacturing company is used to verify that this research approach is suitable for evaluating and managing product complexity in product families. / Ph. D.

This thesis work is based on the previous researches in design automation at Sandvik Coromant. The concept of product family description (PFD) has been introduced to the company to improve documentation of knowledge in engineering design process. Current documentation at the company for engineering design covers mostly the design definition part of the knowledge. PFD is constituted by design definition and completed by design rationale. This kind of documentation improves reusing, revising and expanding the knowledge at the company. On the other side, PFD is an input for design programming and a good engineering design description for a product provides more efficiency in design programming. The project is started by a survey for several principles and applications for knowledge modelling. Product variant master (PVM) and Semantic MediaWiki are selected by the results of the survey. To show the concept of PVM, modelling of a test product is done in product model manager (PMM) software. The main part of the project is setting up product family description (PFD) by capturing design rationale for the test product, implementing in Semantic MediaWiki. Since the design rationale is not documented, it was recorded during several meetings with the designer of the test product. The description is completed by including the argumentations about the rules, figures, dimensions and etc. Also in the project has been tried to improve and revise the description to make it more simple and efficient. Another objective of the project is to show Semantic MediaWiki as a candidate application for modelling knowledge at the company. In this step the applicability and functionality of both PFD and Semantic MediaWiki is seen. In the next stage the project findings and company documentation are evaluated. In this step has been tried to show the pros and cons of the project. The emphasis of the evaluation is on PFD and the alternative application. In the end a conclusion of the whole methods and findings of the project comes with discussion with people who were involved in this work.