Embodiment Design: Product Architecture & Configuration Design Chapter 8 Part 1 Dieter/Schmidt, Engineering Design 5e. ©2013. The McGraw-Hill Companies

Embodiment Design in PDP Dieter/Schmidt, Engineering Design 5e. ©2013. The McGraw-Hill Companies

Introduction We have divided the embodiment phase of design lectures into three groups of: Product Architecture: Arranging the physical elements of a design in order to carry out it’s functions Setting the arrangement of the physical elements of the design into groupings, called modules. Configuration Design: The design of special-purpose parts and the selection of standard components, like pumps or motors. Parametric Design: Determining the exact values, dimensions, or tolerances of the components or component features that are deemed critical-to- quality. Dieter/Schmidt, Engineering Design 5e. ©2013. The McGraw-Hill Companies

What is product architecture? Dieter/Schmidt, Engineering Design 5e. ©2013. The McGraw-Hill Companies

Product Architecture Product architecture is the arrangement of the physical elements of a product to carry out its required functions. A product’s architecture is related to its function structure, but it does not have to match it. A product’s architecture is selected to establish the best system for functional success once a design concept has been chosen. There are two entirely opposite styles of product architecture: modular integral Dieter/Schmidt, Engineering Design 5e. ©2013. The McGraw-Hill Companies

Modular Architecture A modular architecture makes it easier to evolve a design over time. The product can be adapted to the needs of different customers by adding or deleting modules. Modular design may even be carried to the point of using the same set of basic components in multiple products, creating a product family. Dieter/Schmidt, Engineering Design 5e. ©2013. The McGraw-Hill Companies

Types of Modular Architectures Slot-modular: Each of the interfaces between modules is of a different type from the others. Bus-modular: The modules can be assembled along a common interface, or bus. Sectional-modular: All interfaces are of the common type, but there is no single element to which the other chunks attach. Dieter/Schmidt, Engineering Design 5e. ©2013. The McGraw-Hill Companies

Integral Architecture In an integral architecture the implementation of functions is accomplished by only one or a few modules. In integral product architectures, components perform multiple functions. When a component provides more than one function it enables function sharing. Product architecture has strong implications for manufacturing costs. Dieter/Schmidt, Engineering Design 5e. ©2013. The McGraw-Hill Companies

8.3 Steps in Developing Product Architecture What are the steps in developing product architecture? Dieter/Schmidt, Engineering Design 5e. ©2013. The McGraw-Hill Companies

Four-Step Process for Establishing Product Architecture Ulrich and Eppinger propose a four-step process for establishing product architecture: Create a schematic diagram of the product Cluster the elements of the schematic Create a rough geometric layout Identify the interactions between modules Dieter/Schmidt, Engineering Design 5e. ©2013. The McGraw-Hill Companies

Schematic Diagram: Shot-Buddy Example Showing Flows Adapted from J. Davis, J. Decker, J. Maresco, S. McBee, S. Phillips, and R. Quinn, “JSR Design Final Report: Shot-Buddy,” unpublished, ENME 472, University of Maryland, May 2010. Dieter/Schmidt, Engineering Design 5e. ©2013. The McGraw-Hill Companies

Schematic Diagram: Shot-Buddy Example Clustered into Modules Adapted from J. Davis, J. Decker, J. Maresco, S. McBee, S. Phillips, and R. Quinn, “JSR Design Final Report: Shot-Buddy,” unpublished, ENME 472, University of Maryland, May 2010. Dieter/Schmidt, Engineering Design 5e. ©2013. The McGraw-Hill Companies

Geometric Layout: Shot-Buddy Example Adapted from J. Davis, J. Decker, J. Maresco, S. McBee, S. Phillips, and R. Quinn, “JSR Design Final Report: Shot-Buddy,” unpublished, ENME 472, University of Maryland, May 2010. Dieter/Schmidt, Engineering Design 5e. ©2013. The McGraw-Hill Companies

Define Interactions & Determine Performance Characteristics The most critical task in determining a product’s architecture is accurately modeling the interactions between the modules and setting the performance characteristics for the modules. Function happens primarily at the interfaces between modules, and unless modules are carefully thought out, complexity can build up at these interfaces. The most critical items in the module description are the descriptions of the interfaces and the modeling of interactions between neighboring modules. Dieter/Schmidt, Engineering Design 5e. ©2013. The McGraw-Hill Companies

Documentation of Module The documentation on each module should include: Functional requirements Drawings or sketches of the module and its component parts Preliminary component selection for the module Detailed description of placement within the product Detailed descriptions of interfaces with neighboring modules Accurate models for expected interactions with neighboring modules Dieter/Schmidt, Engineering Design 5e. ©2013. The McGraw-Hill Companies

Interactions Between Component Modules There are four types of interactions possible between component modules: Spatial interactions describe physical interfaces between modules. Energy flows between modules represent another important type of interaction. Information flow between modules often takes the form of signals to control the product’s operation or feedback relative to that operation. Material can flow between product modules if that is an element of the product’s functionality. Dieter/Schmidt, Engineering Design 5e. ©2013. The McGraw-Hill Companies

What is configuration design? Dieter/Schmidt, Engineering Design 5e. ©2013. The McGraw-Hill Companies

Configuration Design In configuration design we establish the shape and general dimensions of components. Exact dimensions and tolerances are established in parametric design. The term component is used in the generic sense to include special-purpose parts, standard parts, and standard assemblies. A part is characterized by its geometric features such as holes, slots, walls, ribs, projections, fillets, and chamfers. The arrangement of features includes both the location and orientation of the geometric features Dieter/Schmidt, Engineering Design 5e. ©2013. The McGraw-Hill Companies

Terms Used in Configuration Design A standard part is one that has a generic function and is manufactured routinely without regard to a particular product. Bolts, Washers, Rivets, and I-beams. A special-purpose part is designed and manufactured for a specific purpose in a specific product line. An assembly is a collection of two or more parts. A subassembly is an assembly that is included within another assembly or subassembly. A standard assembly is an assembly or subassembly that has a generic function and is manufactured routinely. Electric motors, Pumps, Gearboxes. Dieter/Schmidt, Engineering Design 5e. ©2013. The McGraw-Hill Companies

Possible Configurations of Features Four possible configurations of features for a right-angle bracket: Dieter/Schmidt, Engineering Design 5e. ©2013. The McGraw-Hill Companies

Interrelationship between Function and Form Adapted from D. Ullman, The Mechanical Design Process, 4th ed., McGraw-Hill, New York,2010. Dieter/Schmidt, Engineering Design 5e. ©2013. The McGraw-Hill Companies

Starting Steps for Configuration Design Review the product design specification and any specifications developed for the particular subassembly to which the component belongs. Establish the spatial constraints that pertain to the product or the subassembly being designed. Create and refine the interfaces or connections between components. Before spending much time on the design, answer the following questions: Can the part be eliminated or combined with another part? Can a standard part or subassembly be used? Dieter/Schmidt, Engineering Design 5e. ©2013. The McGraw-Hill Companies

Progression of a Design Configuration Dieter/Schmidt, Engineering Design 5e. ©2013. The McGraw-Hill Companies

Activities of Configuration Design Refining is a natural activity as we move through the design process in which we develop more specificity about the object as we move from an abstract to a highly detailed description. Patching is the activity of changing a design without changing its level of abstraction. Substituting looks for other concepts, components, or features that will work in place of the current idea. Combining aims to make one component replace multiple components or serve multiple functions. Decomposing is the opposite approach from combining. Magnifying involves making some feature of a component larger relative to adjacent components. Minifying involves making some feature of a component smaller. Rearranging involves reconfiguring the components or their features. Dieter/Schmidt, Engineering Design 5e. ©2013. The McGraw-Hill Companies

Details a Designer Must Consider in Configuring a Bolted Connection Y. Hatamura, The Practice of Machine Design, Oxford University Press, Oxford, UK, 1999, p. 78. Dieter/Schmidt, Engineering Design 5e. ©2013. The McGraw-Hill Companies

Analyzing and Evaluating Configuration Designs The first step in analyzing the configuration design of a part is the degree to which it satisfies the functional requirement and product design specification (PDS). Alternative configuration designs of a part should be evaluated at the same level of abstraction. The analysis used for this decision is fairly rudimentary, because the objective at this stage is to select the best of several possible configurations. A body of guidelines that result in best practice for design for manufacture and design for assembly have been developed to assist designers in this area. Dieter/Schmidt, Engineering Design 5e. ©2013. The McGraw-Hill Companies

Typical Design For Function Dieter/Schmidt, Engineering Design 5e. ©2013. The McGraw-Hill Companies

Best Practices for Configuration Design Clarity of function pertains to an unambiguous relationship between the various functions and the appropriate inputs and outputs of energy, material, and information flow. Simplicity refers to a design that is not complex and is easily understood and readily produced. Safety should be guaranteed by direct design, not by secondary methods such as guards or warning labels. Minimal impact on the environment is of growing important, and should be listed as a fourth basic guideline. Dieter/Schmidt, Engineering Design 5e. ©2013. The McGraw-Hill Companies

Design Guidelines Four special mentioned design guidelines given by Pahl and Beitz: Force Transmission Division of Tasks Self-help Stability Dieter/Schmidt, Engineering Design 5e. ©2013. The McGraw-Hill Companies

Force Transmission In mechanical systems the function of many components is to transmit forces and moments between two points. This is usually accomplished through a physical connection between components. The force should be accommodated in such as way as to produce a uniformly distributed stress on the cross section of the part. A method for visualizing how forces are transmitted through components and assemblies called force-flow visualization is to think of forces as flow lines, analogous to low-turbulence fluid flow streamlines or magnetic flux. Dieter/Schmidt, Engineering Design 5e. ©2013. The McGraw-Hill Companies

Yoke Connection Adapted from R. C. Juvinall, K.M. Marshek, Fundamentals of Machine Component Design, 4th ed., John Wiley & Sons, Hoboken, NJ, 2006. Dieter/Schmidt, Engineering Design 5e. ©2013. The McGraw-Hill Companies

Division of Tasks The question of how rigorously to adhere to the principle of clarity of function is ever present in mechanical design. A component should be designed for a single function when the function is deemed critical and will be optimized for robustness. Assigning several functions to a single component (integral architecture) results in savings in weight, space, and cost by may compromise the performance of individual functions, and it may unnecessarily complicate the design. Dieter/Schmidt, Engineering Design 5e. ©2013. The McGraw-Hill Companies

Self-Help The idea of self-help concerns the improvement of a function by the way in which the components interact with each other. A self-reinforcing element is one in which the required effect increases with increasing need for the effect. A self-damaging effect is the opposite. A self-protecting element is designed to survive in the event of an overload. One way to do this is to provide an additional force- transmission path that takes over at high loads, or a mechanical stop that limits deflection. Dieter/Schmidt, Engineering Design 5e. ©2013. The McGraw-Hill Companies

Stability The stability of a design determines whether the system will recover appropriately from a disturbance to the system. The ability of a ship to right itself in high seas is a classic example. Sometimes a design is purposely planned for instability: Toggle device on a light switch. Dieter/Schmidt, Engineering Design 5e. ©2013. The McGraw-Hill Companies

Additional Design Suggestions Tailor the shape to the stress or load distribution. Avoid geometry that is prone to buckling. Use triangular shapes and structures. Don’t ignore strain considerations in design. Figure above right J. G. Skakoon, “Detailed Mechanical Design,” ASME Press, New York, 2009, p. 114. Dieter/Schmidt, Engineering Design 5e. ©2013. The McGraw-Hill Companies

Interfaces and Connections Fixed, nonadjustable connection Adjustable connection Separable connection Locator connection Hinged or pivoting connection Dieter/Schmidt, Engineering Design 5e. ©2013. The McGraw-Hill Companies

Geometrical Constraint in 2-D . J. G. Skakoon, “Detailed Mechanical Design,” ASME Press, New York, 2009. Dieter/Schmidt, Engineering Design 5e. ©2013. The McGraw-Hill Companies

Checklist for Configuration Design(1) Identify the likely ways the part might fail in service: Excessive plastic deformation Fatigue failure Stress Concentrations Buckling Shock or Impact loads Identify likely ways that part functionality might be compromised: Tolerances Creep Thermal deformation Dieter/Schmidt, Engineering Design 5e. ©2013. The McGraw-Hill Companies

Checklist for Configuration Design(2) Materials and manufacturing issues: Prevent failure modes in service History of use for the material Form and features Standard quality specifications Material & manufacturing process Design knowledge base: Knowledge of the team Unfortunate, unlikely, or unlucky event Dieter/Schmidt, Engineering Design 5e. ©2013. The McGraw-Hill Companies

Design Catalogs Design catalogs are collections of known and proven solutions to design problems. They contain a variety of information useful to design, such as: Physical principles to achieve a function Solutions of particular machine design problems Standard components Properties of materials. Dieter/Schmidt, Engineering Design 5e. ©2013. The McGraw-Hill Companies

Designs for Fixing and Connecting two Components Y. Hatamura, The Practice of Machine Design, Oxford University Press, Oxford, UK, 1999. Dieter/Schmidt, Engineering Design 5e. ©2013. The McGraw-Hill Companies