Engineering Design and Product Development

Product development is challenging for companies developing complex products, such as aircrafts, cars, trucks and big civil infrastructures. These types of products are composed of many multidisciplinary systems. Such systems are constructs of interrelated parts forming a complex whole (Blanchard and Fabrycky 2006), functioning together to achieve goals which cannot be attained by the elements alone (Clayton and Backhouse 2012).

The development process in systems engineering is commonly viewed in the literature as a decomposition process followed by an integration process (Pugh (1990), Krishnan and Ulrich (2001), Pahl and Beitz (2013)). During the decomposition process, the customers’ requirements are analysed and defined in engineering terms and then partitioned into a set of specifications for several systems or components. The design process defines what the system have to do, how well the system must do it, and how the system should be tested to verify the and validate the system’s performance.

The engineering design process illustrated in Figure 2-1, consists of a number of steps to find an optimal solution to a specific problem. Throughout this process there is considerable feedback and several iterations. First there is a definition of the need and the specification of the requirements for the system. This is followed by an investigation of possible solutions to the stated problem, leading to a conceptual design. The conceptual design is then analysed and refined, until it becomes a detailed design including the adopted solution and the system characteristics. The detailed design is then implemented through the process of developing, testing and product launch.

Figure 2-1 The design process adapted from Pahl and Beitz (2013)

The classical model of product development follows a sequential staging of design and development tasks. However, designing a product can be used in its narrow sense to refer to the design phase. As shown in Figure 2-2, the design activity starts by developing the product concept based on existing technical knowledge and the customer needs. As the process unfolds, the company develops new knowledge about how components correlate and interact in the product before getting to the detailed design. This knowledge gained throughout each stage enables design decisions which allow the next stage of development tasks to proceed.

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Figure 2-2 Product development process adapted from Ulrich and Eppinger (2000)

However, some other research makes evident the likelihood of losses and delays in information flow, when product development processes are organised in a sequential way. Thus, another possible representation of the product development process described in the literature is shown in Figure 2-3 (adapted from Buede and Miller, 2016) beginning with the identification of need for the system and progressing through the retirement of the system. Some of the phases of the process are accomplished in parallel, as shown in the diagram; which phases occur in parallel depends upon the type of system, the organisation, and the context.

The product development phases associated with the engineering design are shaded in Figure 2.3. Design includes the preliminary system design as well as parts of the identification of need and concept definition.

Figure 2-3 Product development process adapted from Buede and Miller (2016)

On the other hand, traditional approaches in product design and manufacture consider only limited information on the manufacturing issues. The concept of concurrent engineering (CE) is then introduced and many researchers such as Yassine and Wissmann (2007), Eastman (2012), Hartley (2017) argue that CE is a way to reduce the lead time between the start of a design and the manufacture of a product by ensuring that manufacturing issues are considered from the beginning of product design. However, this type of approach might not be applicable for all the engineering systems due to the complexity and the uncertainty associated with the product development.

Another approach to the classical development model is the gate review process which has been adopted by most companies in the automotive sector. This development process controls and coordinates design efforts and provides baselines guiding the development, production and operation of the system. The system's life-cycle is normally split into several stages, as shown in Figure 2-4.

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Figure 2-4 Product development process and decision gate at each stage. Adapted from Blanchard and Fabrycky (2006) and Volvo GDP.

The conceptual design stage is the first phase in complex system development and follows the approval of a new development initiative inside the organisation. It typically includes the identification of stakeholder needs, requirements capture, concept exploration and design and the overall programme planning. The preliminary design stage occurs subsequently, to refine the system's conceptual solution and typically includes the preliminary definition of the key sub- systems and components. Detailed design and development follow with the full definition of sub-systems and components together with all the prototype development and testing activities and verification of internal and supplier manufacturing capabilities. Subsequent production approval triggers the start of large-scale manufacturing and the beginning of continuous system deliveries to the customer. The system is then put into operation and the last stage includes maintenance and logistic support to the customer, the release of product improvements and collection and analysis of operational data (Blanchard and Fabrycky (2006)).

These and other typical activities are performed during the stages of the system's life-cycle and are described in Figure 2-4, together with the typical decision gates in each stage. Major technical and business reviews (e.g. Concept Review, Preliminary Design Review, and Production Release Review) take place at each decision gate. Decision options at each gate, determine whether the team should move to the next stage or an iteration should be made in the current stage before moving to the next one.

While most published research on product development is focused on designing new systems or products, this is rarely the case in the automotive industry where products are often reusing systems or components from the previous generation or using shared systems or components across different products.