1. TEMPLATE DESIGN © 2008
www.PosterPresentations.com
Lexey R. Sbriglia, James M. Thompson, Adam J. Wachtor, John D. Bernardin
(Contact: lsbriglia@lanl.gov, 667-3391)
Conclusion/Discussion
Simulation ResultsExperimental Method
References
Background & Motivation
Eigenvalue solutions for natural frequencies of
the part were found using SolidWorks Simulation.
[1] Kessler, S.S., Spearing, S.M., Atalla, M.J., Cesnik, C.E.S., & Soutis, C. (2002). Damage
Detection in composite materials using frequency response methods, Composites: Part B,
33, 87-95.
[2] White, C., Li, H.C.H., Whittingham, B., Herzberg, I., & Mouritz, A.P. (2009). Damage detection in
repairs using frequency response techniques. Composite Structures, 87, 175-181.
[3] Start, B., Stevenson, B., Stow-Parker, K., & Chen, Y. (2014). Embedded sensors for health
monitoring of 3D printed unmanned aerial systems, ICUAS, 175-180.
A baseline procedure has been developed for
further exploration of FDM print parameters. A program
and excitation settings have been documented for
consistent data collection and analysis. This work has
narrowed down the material to PLA for future parts, as
the quality of the build is important for attaching
accelerometers.
Follow on work will further develop and test this
embedded technique for possible applications to SoH
monitoring in deployed systems [3] and real-time
diagnostics and control of the build process.
Automation of sensor placement within the print will be
performed using a programmed mechanical arm to
insert the accelerometer into the build.
Increased availability of open source fused
deposition modeling (FDM) machines has expanded
the parameter space for additive manufacturing
applications in which the user has control during the
build process. Using a LulzBot TAZ 5, changes in the
most common parameters were tested for part quality
and reproducibility.
Modal analyses were performed on completed
builds [1, 2] using an electrodynamic shaker and
integrated circuit piezoelectric accelerometers
embedded in the parts during the build process.
Experimental modal measurements of the FDM parts
were benchmarked against simulation results for the
natural frequencies of an idealized part with
homogenous material properties.
Mode 1 2 3 4 5
ABS (Hz) 897 898 2836 4077 4124
HIPS (Hz) 866 867 2737 3936 3981
PLA (Hz) 1067 1068 3428 4871 4927
Material
Nozzle Temperature
Plate Temperature
Print Speed
Fan Speed
Layer Thickness
Shell Thickness
Infill %
Support Material
Feed Rate
Retraction
Z-Hop Level
Mode 1 –1067 Hz
Mode 5 – 4927 Hz
Mode 4 – 4871 HzMode 3 –3428 Hz
Mode 2 –1068 Hz
Mode 6 – 5646 Hz
PLA
www.lulzbot.com
LA-UR # :15-26136
Objectives
• Quantify the effects that common operator choices
have on the quality and reproducibility of the build.
• Provide ground work for creating a technique for
possible applications to state-of-health (SoH)
monitoring in deployed systems [3].
• Enumerate printer limitations to avoid user induced
failure.
• Assess damage in parts via experimental modal
analysis.
Embedded Sensors
PCB 352A21 accelerometers were chosen for
their small size, operating temperature range, and
response specifications.
• Half printed parts were used to
assess the performance of
different bonding agents.
• Fully embedded sensors for
simple SoH monitoring.
ccrma.stanford.edu
• Data acquisition hardware is used to collect time
domain data during a frequency sweep from 50Hz
to 10kHz.
• LabView is used to perform a Fourier Transform,
breaking the data into it’s subsequent sinusoids.
• The resulting graph depicts the frequency response:
a graph high-lighting the frequencies with significant
amplitude.
• Decrease in amplitude indicates damage which is
caused by a decrease in the stiffness ratio.
Brüel & Kjӕr Electrodynamic Shaker System
SHAKER
CONTROLLER
AMPLIFIER
𝑚𝑚 ̈𝑥𝑥 = −𝑘𝑘𝑘𝑘 → 𝑥𝑥 = 𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴 𝐴𝐴𝐴𝐴 = 𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴
𝑘𝑘
𝑚𝑚
𝑡𝑡
The motion of a mass-spring system is sinusoidal
in nature. Multiple systems can comprise a single
system. The same concept applies to a Fourier
Transform; the time domain data is comprised of many
sinusoidal frequencies. The amplitude of the natural
frequencies is visible in the resulting graph.
• Contrary to predictions, the
peak remained at the same
location throughout all parts.
• The peak could be caused by
a driving frequency of the
modal shaker.
• The amplitude of the peak
decreases due to a loss of
stiffness in the materials.
• The drawing should reduce
the driving frequency from the
shaker by reducing surface
area affected by the shaker.