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Conference Presentations by Rahul Rai

The development of manufacturing technologies for new materials involves the generation of a larg... more The development of manufacturing technologies for new materials involves the generation of a large and continually evolving volume of information. The analysis, integration and management of such large volumes of data, typically stored in multiple independently developed databases, creates significant challenges for practitioners. There is a critical need especially for open-sharing of data pertaining to engineering design which together with effective decision support tools can enable innovation. We believe that ontology applied to engineering (OE) represents a viable strategy for the alignment, reconciliation and integration of diverse and disparate data. The scope of OE includes: consistent capture of knowledge pertaining to the types of entities involved; facilitation of cooperation among diverse group of experts; more effective ongoing curation, and update of manufacturing data; collaborative design and knowledge reuse. As an illustrative case study we propose an ontology focused

Papers by Rahul Rai

Computer-Aided Design, 2016

Volume 1A: 35th Computers and Information in Engineering Conference, 2015

Volume 4: 20th Design for Manufacturing and the Life Cycle Conference; 9th International Conference on Micro- and Nanosystems, 2015

Additive manufacturing (AM) is a leading technology in various industries including medical and a... more Additive manufacturing (AM) is a leading technology in various industries including medical and aerospace for prototype and functional part fabrication. Despite being environmentally conscious, avenues pertaining to further reducing the impact of AM on the environment exist. Material wastage and energy consumption are two major concerns of the process that requires immediate attention. In this research, a multi-step optimization enabling additive manufacturing process towards energy efficiency is developed. Process objectives such as material waste and energy consumption are minimized both in part and layer domain. Numerous examples are presented to demonstrate the applicability of the developed approach. The models formulated here for selective laser sintering (SLS) process can be easily extended to other additive manufacturing technologies. * Corresponding Author

Increasing manufacturing competition has necessitated simultaneous design of multiple products. V... more Increasing manufacturing competition has necessitated simultaneous design of multiple products. Various design strategies such as Design for Variety (DfV) and product family design have become critical in this respect. This paper provides a new generic approach, which combines aspects of function architecting, multi-objective optimization, and multi agent systems to tackle product platform problems related to multiple product design (MPD). The approach uses functional architecting methods to determine various modules based on functional requirements. Multi-objective optimization using an adaptive multi-agent framework is then used to determine Pareto-design solutions that satisfy various constraints such as module compatibility. Post optimization analysis is applied on the Pareto-design solution set to determine the optimal product platform for the product family. The proposed method is applied to a MPD example to demonstrate its validity and effectiveness.

SFF has been instrumental in improving the design process by providing designers with prototypes ... more SFF has been instrumental in improving the design process by providing designers with prototypes that assist them in the communication of design information and design visualization prior to creating fully functional prototypes. Embedding sensors at key locations within an SFF part to extract further data and monitor parameters at critical locations not accessible to ordinary sensors can help immensely in building functional SFF parts. However, this approach requires data acquisition of information such as temperature and strain values from interiors of products. In this work, the authors propose new techniques for embedding thermal sensors and strain gauges into fully dense DuraForm™ during Selective Laser Sintering (SLS) process. The embedded sensors have been used to measure temperatures and strains. They provide higher sensitivity, good accuracy, and high temperature capacity.

This paper presents a systematic way of thinking about computational synthesis methods in enginee... more This paper presents a systematic way of thinking about computational synthesis methods in engineering design. By studying how various researchers present their work and through personal experiences, the authors have found that by dividing these problems into representation, generation, evaluation, and guidance challenges, one can more easily tackle difficult problems. This paper presents this division along with a brief literature review of papers that either implicitly or explicitly coheres to this division.

The objective of this paper is to understand and study sustainable product development using a sy... more The objective of this paper is to understand and study sustainable product development using a systems approach. In the real world, artifacts interact with each other to form a web structure (known as artifact system (AS)), which has its own laws of evolution. Specifically, this paper focuses on development of "Factor X" model to study the diffusion of ecoinnovation strategies. The concept of "Factor X" is qualitatively similar to the concepts of "eco-efficiency," and "dematerialization," but has a quantitative edge. It focuses on reducing the environmental impact of economic activities in quantitative terms. We have implemented the "Factor X" framework through adaptive agent based simulation (AABS) model to study the implications of different AS scenarios (achieved by setting system defining parameters) on the propagation and extent of diffusion of eco-innovation strategies.

Additive manufacturing processes are capable of printing parts with any shape and complexity. The... more Additive manufacturing processes are capable of printing parts with any shape and complexity. The parts fabricated with additive manufacturing processes requires minimum human intervention. Process planning decisions play an important role in making sure the fabricated parts meets the desired specification, including the build time and cost. A quick and unified approach to quantify the manufacturing build time, accuracy, and cost in real time is lacking. In the present research, a generic and near real-time framework for unified additive manufacturing process planning is presented. We have developed computational geometric solutions to estimate tight upper bound of manufacturing process planning decisions that can be analyzed in almost real time. Results of developed computational approach are compared against the optimized process plans to ensure its applicability. Case studies comprising of numerous parts with varying shape, and application area is also outlined.

Http Dx Doi Org 10 1080 0020754031000149248, Nov 14, 2010

The advent of mass customization and increased manufacturing competition has necessitated that ma... more The advent of mass customization and increased manufacturing competition has necessitated that many companies offer platform-oriented multiple product variants. Various design strategies such as Design for Variety and product family design have become critical in this respect. This paper provides a two-step approach to tackle the modular product family design problem. The first step performs a multi-objective optimization using a multi-agent framework to determine the Pareto-design solutions for a given module set. The proposed multiagent framework is new and has built in flexibility to handle various constraints such as module compatibility during the optimization process. The second step performs post-optimization analysis that includes a novel application of the quality loss function to determine the optimal platform level for a related set of product families and their variants. The proposed method is applied to a product family design example to demonstrate its validity and effectiveness.

Volume 8: 14th Design for Manufacturing and the Life Cycle Conference; 6th Symposium on International Design and Design Education; 21st International Conference on Design Theory and Methodology, Parts A and B, 2009

This paper presents a new search method that has been developed specifically for search trees def... more This paper presents a new search method that has been developed specifically for search trees defined by a generative grammar. Generative grammars are useful in design as a way to encapsulate the design decisions that lead to candidate solutions. Since the candidate solutions are not confined to a single configuration or topology and thus useful in conceptual design, they may be difficult to computationally analyze. Analysis is achieved in this method by querying the user. The user interaction is kept to a maximum of thirty pair-wise comparisons of candidates. From the data gathered from the comparisons, a stochastic decision making process infers what candidate solutions best meet the user's preference. The method is implemented and applied to a grammar for tying neckties. It is shown through 21 user experiments and 4000 automated experiments that the method consistently finds solutions within the 99.8 percentile. The implications of this method for conceptual design are expounded on in the conclusions.

Abstract: Over the last decade, there has been a continuous increase in the demand of hard disk d... more Abstract: Over the last decade, there has been a continuous increase in the demand of hard disk drives (HDDs) for the mobile applications. In such devices, HDDs are often subjected to mechanical shocks and vibrations. Such external disturbances can degrade the read/write ...

Volume 9: 23rd International Conference on Design Theory and Methodology; 16th Design for Manufacturing and the Life Cycle Conference, 2011

ABSTRACT Multi billion people exist at the bottom of the global economic pyramid (BOP). Increased... more ABSTRACT Multi billion people exist at the bottom of the global economic pyramid (BOP). Increased consumer demand and enormous volume has helped turn these BOP into emerging markets with substantial profit potential. Current approaches for designing product and service solutions for BOP markets are ad-hoc in nature. Product Service Systems (PSS), products intertwined with services, can be highly adaptable to these emerging markets and provide an unique framework for designing solutions in the emerging BOP markets. This paper systematically approaches the problem of designing customized PSSs for emerging markets. The approach is based on results of an empirical study of multiple cases of existing successful products and services designed for BOP markets. As part of the study various cases are analyzed and high level principles for designing PSSs are derived from the empirical data. The utility of the approach is demonstrated through the conceptual design of a healthcare PSS for emerging markets.

Volume 7: 2nd Biennial International Conference on Dynamics for Design; 26th International Conference on Design Theory and Methodology, 2014

Computer-Aided Design, 2016

Volume 1A: 35th Computers and Information in Engineering Conference, 2015

Volume 4: 20th Design for Manufacturing and the Life Cycle Conference; 9th International Conference on Micro- and Nanosystems, 2015

Http Dx Doi Org 10 1080 0020754031000149248, Nov 14, 2010

Volume 9: 23rd International Conference on Design Theory and Methodology; 16th Design for Manufacturing and the Life Cycle Conference, 2011

Volume 7: 2nd Biennial International Conference on Dynamics for Design; 26th International Conference on Design Theory and Methodology, 2014

Volume 5: 37th Design Automation Conference, Parts A and B, 2011

Automated concept generation is non-trivial task. The complexity of this problem is mainly due to... more Automated concept generation is non-trivial task. The complexity of this problem is mainly due to lack of formal representation frameworks that lend themselves easily to a computational approach. Generative grammar has emerged as a potential solution to this problem and presents a number of different possibilities for conceptual design automation. This paper presents a novel search method that has been developed specifically for search trees defined by a special class of generative grammar in which rules of the grammar have parameters associated with them. A novel feature of the proposed search is 'Human in the loop' approach in which learning about the search space is achieved by querying the user. The user fatigue restricts the maximum number of comparisons of candidate solutions (30-50). From the data gathered from the comparisons, a stochastic decision making process proposed in this paper quickly converges to a region of design space which best meet the user's preference. The method is implemented and applied to a grammar for shampoo bottle concept generation. It is shown through multiple userguided and automated experiments that the method has ability to learn and adopt through human computer interaction process. The implications of the proposed search method for automated conceptual design are expounded on in the conclusions.