WINTER 2016

124 THE DISTRIBUTOR’S LINK
JIM STEELE ANEWWASHERCANACCURATELYMEASUREABOLT’SCLAMPINGFORCE from page 30
Tests getting underway now will involve determining
an appropriate low-cost material in which to embed the
piezoelectric filaments, vibration and temperature testing
and trials to accumulate the data necessary to provide
accurate preload readings.
“Two things we are after are accuracy and to keep
the costs down,” says Dr. Wang. “We want to test so
that we can be sure that when a technician tightens a
bolt he gets that specific value he is looking for every
time.”
Because a piezoelectric load cell is ceramic and
fragile, the tests will also provide information about
optimizing washer design to avoid breaking the sensing
elements.
“You don’t want a force directly applied to the piezo
matter; you will break it,” Dr. Wang says. Since that
renders the washer’s measuring capability useless, the
washer’s metallic elements must be designed to carry
the majority of the load.
“We are also looking at what type of material we
should use to surround the piezo material that will
protect it best,” he says. “That way we can be sure the
piezo element will provide an accurate reading and not
break.”
If the elements can be preserved, the washer could
be used many times.
“There should be no reason,” Dr. Hissam says, “that
it can’t be reused.”
About Dr. Gang Wang
Dr. Gang Wang, Assistant Professor, Department of
Mechanical and Aerospace Engineering (MAE) at the
University of Alabama in Huntsville (UAH) --Dr. Wang
received MS and PhD degrees from the University of
Maryland, College Park, in Aerospace Engineering from
the Alfred Gessow Rotorcraft Center in 1998 and 2001,
respectively. His areas of research include: Solid
Mechanics; Adaptive Structures; Rotorcraft and Emerging
Technologies. Before joining UAH in August 2010, Dr.
Wang was employed with Techno-Sciences Inc. as a
Principal Engineer. He directed and performed research
development focused on rotorcraft systems
technologies, smart materials, advanced actuators and
controls for vehicle performance enhancement, vibration
and shock control, mechanical and dynamic analysis,
and test and evaluation of prototype aerospace systems.
He has authored 24 archival journals and presented
more than 35 technical papers in professional
conferences related to smart structures and structural
dynamics research. Due to his exceptional contribution,
Dr. Wang received the American Institute of Aeronautics
and Astronautics (AIAA) National Capital Section's
prestigious Young Engineer/Scientist of the Year Award
in 2006.
Dr. Wang is Technical Committee member of the
Adaptive Structures & Material Systems Committee
(ASMS) under Aerospace Division of the ASME. He is a
co-inventor of three US Patents. Dr. Wang is an
Associate Fellow of the AIAA (elected in 2013) and a
member of the ASME and AHS.
About Dr. Andy Hissam
Dr. Andy Hissam, the Team Lead for the Propulsion
Detailed Design Branch (ER34) at the Marshall Space
Flight Center (MSFC). Dr. Hissam earned his PhD and MS
degrees in mechanical engineering from the University of
Alabama in Huntsville and his BS degree in mechanical
engineering from the University of Kentucky. In addition,
Dr. Hissam has a BS degree in geology, also from the
University of Kentucky. He has been a registered
Professional Engineer (PE) in the state of Alabama since
1998.
His interest in threaded fasteners started as a co-op
student in the late 1980’s. Working at a small research
and development firm, he learned about fastener preload
and its importance in the safety and reliability of joints.
Since then, he has worked on hundreds of mechanical
designs that rely on fastener preload to operate properly.
Dr. Hissam currently has over 25 years of experience in
functional and detailed mechanical design, working at
the MSFC since 1991. Over this time, he has supported
a wide range of projects involving both traditional and
advanced propulsion systems. In almost all cases, these
systems relied on preloaded fasteners.
JIM STEELE | UNIVERSITY OF ALABAMA IN HUNTSVILLE