|
Energy Harvesting & Design Optimization Lab. |
||||||||||||||
|
University
of Maryland Baltimore County, Dept. of Mechanical Engineering |
||||||||||||||
|
|
||||||||||||||
|
|
||||||||||||||
|
|
||||||||||||||
|
Completed Topics – Energy Harvester / Topology Optimization / Shape Optimization / RBDO
1.
Design of Six-Axis Force/Torque Sensor for Minimum Crosstalk:
The design optimization of a mechanically
decoupled six-axis force/torque (F/T) sensor is performed for minimization of
cross coupling error. The new term ‘principal coupling’ is proposed to define
the largest cross coupling error. In the first design step of the F/T sensor,
the locations of twenty-four strain gages in a sensor structure are
predetermined and four structural design variables are selected to be
optimized. In the second step, an optimization framework that reduces
principal coupling is developed. Multiple constraints on good isotropic
measurement and safety are considered and formulated using the output strain
of each strain gauge circuit. The optimal design utilizes FEM software and
MATLAB interactively to perform effective shape optimization. As a result of
shape optimization, principal coupling of a six-axis F/T sensor was reduced
from 35% to 2.5% with good isotropy. The final design of the F/T sensor was
fabricated for experimental verification and there was only 0.7% difference
in principal coupling and 5.2% difference in the overall strain output
between the numerical and experimental results. The optimal design results
are expected to provide a design guideline for multi-axis F/T sensors with
significantly reduced cross coupling error, one of the biggest technical
obstacles in developing F/T sensors.
2.
Earthquake-Resistant Design of Nuclear Plant Element:
While working for Korea Atomic Energy
Research Institute (KAERI) in 2007, a national nuclear energy laboratory, the
PI was involved in the research for the design procedure for a nuclear plant
facility to improve overall margin of safety.
The PI set up the design procedure for a
nuclear power plant structure, a spacer grid assembly, to prevent radiation
leaks under a seismic load and improve overall safety. The spacer grid assembly,
an interconnected array of slotted grid straps, is one of the main structural
components of a pressurized light-water reactor (PWR), a kind of nuclear
energy reactor. The assembly takes the role of supporting the nuclear fuel
rods, which experience a severe expansion and contraction, even under harsh
operational conditions such as an earthquake. For the design of the spacer
grid assembly using simulation, the accuracy of the simulation models (finite
element models) was experimentally verified: The impact strength from the
simulation was about 97% of that from the test (see Figure below). The design
optimization for increasing critical bucking load was formulated. The optimal
design of the unit strap in the grid assembly has been found and some design
guidelines for a support grid such as the spring length and the dimple gap
reduction in the unit strap have been provided.
|
||||||||||||||
|
|
||||||||||||||
|
|
Energy Harvesting & Design Optimization
Lab. University of Maryland Baltimore County,
Dept. of Mechanical Engineering 1000 Hilltop Circle, Baltimore, MD, 21250 © 2013 |
|||||||||||||
