April 21, 2017

Redesign - Design Iterations

Planning Design Iterations

Darian W. Unger, Steven D. Eppinger

Given  uncertainties and interdependencies, iteration is inevitable and must be managed effectively. Iteration is defined broadly to include almost any kind of work that involves correction, feedback or

The two tasks are interdependent if each requires information about the other. Many design processes have hundreds or thousands of such cyclically dependent tasks. These feedback cycles, or iterations, have been successfully modeled by the design structure matrix, a system analysis and project management tool useful in mapping iterations, as shown by Eppinger. Interdependent tasks that require feedback are complex and introduce the potential of burdensome and expensive rework if poorly managed.

Effective iteration provides feedback with each round, thus increasing the likelihood of success in the next round.

The scope of iteration can be a telling component of a company’s PD process.  Narrow iteration is intraphase, exemplified by several rounds of interdependent detailed design tasks.  Comprehensive
iteration is cross-phase, exemplified by processes that do not just cycle around a specific part, but rather over a range of process stages from concept to

Iterating over different parts of the PD process can have a wide range of effects. For example, building several prototypes may mitigate technical risk by determining if the product performs to the level of quality promised by design. It may also address risk by providing information on whether the product will satisfy customer needs. An early cross-phase iteration to determine if a potential architecture is reasonable may help managers estimate schedules accurately but will not necessarily mitigate market risk.

World Academy of Science, Engineering and Technology
International Journal of Mechanical, Aerospace, Industrial, Mechatronic and Manufacturing Engineering Vol:7, No:1, 2013

Managing Iterations in Product Design and Development 

K. Aravindhan, Trishit Bandyopadhyay, Mahesh Mehendale, and Supriya Kumar De

Identification  of  what  will  work  and  what  will  not  work  happens  as the design  evolves  with  multiple  iterations  carried  out before  the expected  specifications  are  met.  Terms  like  “iterative”  and “creative” apply to PD.

Iterative rework taxonomy introduced by Richard et al. [2005]  provides  further  classification  –  evolutionary,  avoidable retrospective and avoidable corrective types of rework.  The evolutionary  rework  typically  occurs  when  the  developers could  not  have  known  about  or  foreseen  the  changes  that happen  in  user  requirements,  market  requirement  and design constraints.  Retrospective  rework  occurs  because  developers knew the needs but did not accommodate them for reasons such as lack of time, time to market pressure. Avoidablere work is primarily  the  rework  involved  in  fixing  defects  due to incomplete development.

Ulrich and Eppinger [2000]  define iteration as repeating  an  already  completed  task  to  incorporate  new  information. Iterations  are  inherent  in  design  and  development  since  it  is many a times a heuristic reasoning process.


Entire  product  development  involves  many  decisions  and each  decision  can  either  make  an  improvement  towards  the final product or can be a step back due to it resulting in re-work and  re-design.  The  decisions  determine  whether  the  progress has been made towards achieving the goals or there is a need to rework or iterate the earlier completed work items. Extending the  decision  point  concept  to  product  development  flow  and using  this  concept  to  identify  iteration  probability  is  a  novel idea introduced by the authors. Planned decision points are for example  reviews,  testing,  early  prototyping  etc.  Pre-planned decision points indicate the existence of planning  for iteration
in a product development or possible events in the development flow when iteration may occur. The entire product development can be visualised as a network of decision points to provide insight into identifying the iteration probability of the product development flow.

Multi Body Simulation

Multi Body Simulation or MMS is, a precursor activity, used to accurately simulate the motion of an assembly component relative to others. It incorporates the effects of motion parameters within components of an assembly. While estimating the motion and relevant physical parameters, it can also combine the mates in the assembly, and consequently motion constraints, material properties, mass, and component contacts.

Whilst carrying out the Structural Performance of a large assembly, MMS gives the relevant loading constraints in terms of reactions, displacements, trace paths, and many others. This helps to arrive at faster structural performances of the components.

Other CAE Capabilities Per need, following specific activities are used during product development stages. These helps establish a path for the design driven product development.

Preliminary Engineering Program (PEP): provides baseline specifications of components for Conceptual Design.

Multi Disciplinary Optimization (MDO): Couples product performance thru' various analyses and achieves desired objective

Knowledge Driven Program (KDP): Provides a program based on the statistical mapping of various effects of Design Drivers on the sizing and shaping of product configuration. Relevant CAE activities are extensively used to eliminate its further use, thereby faster validation coupled with time and cost saving.

@ESEC Engineering Simulation Excellence Centre or ESEC@LUMIUM comprise of a dedicated team of CAE Experts seeking the near perfect performance of the product. Team works in collaboration with the design team at various stages, which helps manage risks involved in various phases of the product design and development

With sound theoretical knowledge; baseline specifications of product, its features & guidelines for engineering concepts are established. Customized design driven approaches, considering various disciplines are used to achieve a comprehensive solution. This also helps reducing number of design iterations and lead time. Different product configurations are explored before proceeding towards final analyses. ESEC has the design driven and multi domain expertise that assists in precise definition of boundary condition for analyses. Product is iteratively Simulated, Rectified, Validated and Optimized. Thus, ESEC substantially provides support to Design Teams in critical decision making.

ESEC's CAE practices help reduce product development time and costs while improving product quality, performance and durability.


Top Management Challenges

This article is part of #AtoZChallenge 2017 for Blogging Posts. My Theme for the Challenge is Top Management Challenges - Full List of Articles  http://nraomtr.blogspot.com/2016/12/a-to-z-2017-blogging-challenge-top.html

To Know More About A to Z Blogging Challenge

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