Science and Technology
Dr. Julie Christodoulou is director of the Naval
Materials Science and Technology Division in the Sea
Warfare and Weapons Department of the Office of
Naval Research (ONR).
“We don’t make widgets. We transfer technology to
the widget makers,” she said.
Christodoulou manages a portfolio of science and
technology programs trying to solve complex problems with naval applications. For example, she said the
Navy is interested in novel conformal heat exchangers,
because there’s no reason, other than manufacturing
limitations, to make them in rectangular blocks.
“AM opens a broader design space so we can make
better use of the space available to us. It might have
some benefits to us in very tight spaces that are
common in military systems. The design has to be
approached in a different way because we’re no longer
constrained by traditional manufacturing technologies
and processes. Understanding what we can control
and how we can control it is as important as simply
building it,” Christodoulou said.
ONR has also been working on very compact,
high-efficiency fuel cells for a number of applications.
“When you try to demonstrate a new system in a
laboratory environment you need to make your own
parts. For our fuel cell, the titanium bipolar plate has
a very complicated internal flow path, which was best
made by additive. The team made it in a couple of different variations and generations to find what worked
best and then demonstrated on the Ion Tiger small
long-endurance UAV [unmanned aerial vehicle], developed by the Naval Research Lab,” she said.
Additionally, Christodoulou said there is a great
deal involved in qualifying the materials, processes
and systems used in additive. And it’s important to
build confidence into the process, and make it more
predictable. That calls for real-time sensors and better
predictive tools to ensure that during a build, the result
will have the desired properties, “so that we know
what it is we’re going to have at the end.”
According to Christodoulou, during each AM build
different alloy compositions, heated to different tem-
peratures over different amounts of time, and with
different cooling rates depending on the part dimen-
sions, alter the microstructure of the finished material.
“We are conducting research on the compositional
and process changes that can be made to the more
well-established alloys to deliver the microstructures
and properties we desire. It’s not going to be used for
everything,” she said. “In some cases, the only way to
produce something that can perform a function with
the correct form and fit, and do it elegantly, is with a
“It all comes down to the economics of the process
and the properties that are needed,” Christodoulou said.
“Sometimes the business case is very compelling.”
Not Just Science
“I have world-class experts in many fields, from
energetics, radar propagation or missile control, to
chemical and biological warfare defense, electronic
countermeasures and naval architecture,” said Rear
Adm. Tom Druggan, commander of the Naval Surface
Warfare Center in Washington (NSWC). “We have
experts working on AM at all of our centers.”
Druggan sees AM as a way to make special or oth-
erwise unobtainable parts for deployed or remote units.
“If I had a 3-D printer, and the right technical data
package that would allow me to manufacture it, I could
have that part on the ship in hours instead of days or
weeks. That’s operationally significant, and a huge
enabler,” he said.
Druggan said the Navy’s warfare centers are engaged
with developing standards and certifying parts.
“What happens if a 3-D-printed part is installed and
it fails and someone gets hurt, or pieces of equipment
go bad? What are the standards that are required? NSCW
Corona [Calif.] is looking at how we characterize the
requirements of the machine itself to make them eligible for Navy use. It won’t be tomorrow, but eventually
you’ll see this start to enter the fleet ships as an operational enabler,” Druggan said.
“It’s not just science,” he said. “It’s an emerging
engineering application that adds value to the Navy.” n
Flight deck gear created by additive manufacturing was on display
at the Next Generation Naval Logistics booth April 4 at the Navy
League’s Sea-Air-Space Exposition at National Harbor, Md.