1

Introduction

Additive manufacturing (AM) methods have great potential for promoting transformative research in many fields across the vast spectrum of engineering and materials science. AM is one of the leading forms of advanced manufacturing which enables direct computer-aided design (CAD) to part production without part-specific tooling. Conventional applications, such as tooling, low production parts, biomedical devices and implants, aerospace components and rapid prototyping, all benefit from the flexibility that AM provides. The technology likewise can enable material design and development of metamaterials. While experimental workshops in AM have been held in the past, this workshop uniquely focused on theoretical and computational approaches and involved areas such as simulation-based engineering and science, integrated computational materials engineering, mechanics, materials science, manufacturing processes, and other specialized areas. The full statement of task is shown in Box 1-1.

WORKSHOP OVERVIEW

On October 7-9, 2015, the National Academies of Sciences, Engineering, and Medicine convened a workshop of experts from diverse communities to examine predictive theoretical and computational approaches for various AM technologies. A planning committee (shown on p. v) was established to identify specific workshop topics, invite speakers, and plan

the agenda. The workshop was held at the Keck Center of the National Academies in Washington, D.C., and was sponsored by the National Science Foundation, Sandia National Laboratories, and the National Institute of Standards and Technology.

Wing Kam Liu, serving as chair of the workshop planning committee, opened the workshop with a brief overview of the four focus areas:

1. Theoretical understanding of materials science and mechanics;
2. Computational and analytical methods in AM;
3. Monitoring and advanced diagnostics to enable AM fundamental understandings; and
4. Scalability, implementation, readiness, and transition.

The workshop was organized with three speakers per topic per day for the first two days. Each speaker was asked to identify the necessary short-, intermediate-, and long-term goals to advance predictive methods in AM as well as to address a set of predefined questions for each focus area. The third day of the workshop brought together speakers and attendees from each session to summarize lessons learned and identify unanswered questions.

Liu emphasized that this workshop would not focus on the policies needed to facilitate international collaboration among academic institutions, national laboratories, and industry. However, he noted that there are currently many stumbling blocks inhibiting collaboration, especially relating to intellectual property, and effective policies would be beneficial.

This workshop was organized under the guidance of the United States National Committee on Theoretical and Applied Mechanics (USNC/TAM), which represents the United States in national and international activities related to the broad science of mechanics, including related sciences, engineering, and mathematics. It serves as a focal point for charting future priorities in mechanics-related research, applications, and education and represents the United States in the International Union of Theoretical and Applied Mechanics (IUTAM). IUTAM represents 55 countries and 18 affiliated organizations.

Approximately 50 participants, including speakers, members of the planning committee, invited guests, and members of the public, participated in the 3-day workshop. The workshop was also webcast with nearly 200 online participants and 1,700 total video viewers.

This report has been prepared by the workshop rapporteur as a factual summary of what occurred at the workshop. The planning committee’s role was limited to organizing and convening the workshop. The views contained in the report are those of individual workshop participants and do not necessarily represent the views of all workshop participants, the planning committee, or the National Academies of Sciences, Engineering, and Medicine.

In addition to the workshop summary provided here, materials related to the workshop can be found online at the website of the Board on International Scientific Organizations’ U.S. National Committee for Theoretical and Applied Mechanics,¹ including the agenda, speaker presentations,

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¹ The website for the U.S. National Committee for Theoretical and Applied Mathematics is http://sites.nationalacademies.org/pga/biso/IUTAM/, accessed August 23, 2016.

archived webcasts of the presentations and discussions, and other background materials.

ORGANIZATION OF THIS REPORT

Subsequent chapters of this report summarize the workshop presentations and discussions. Chapter 2 provides an overview of the theoretical understanding of materials science and mechanics, including related physical sciences, engineering, and mathematics, for AM. Chapter 3 focuses on computational and analytical methods in AM. Chapter 4 discusses monitoring and advanced diagnostics to enable fundamental understanding in AM. Chapter 5 provides an overview of scalability, implementation, readiness, and transition considerations for AM. Chapter 6 describes subgroup discussions regarding some of the recurring issues mentioned throughout the workshop as well as topics that need to be examined more closely. Lastly, Appendix A lists the workshop speakers, and Appendix B shows the workshop agenda.