Abstract: The purpose of this study is to derive optimal shapes of
a body located in viscous flows by the finite element method using the
acoustic velocity and the four-step explicit scheme. The formulation
is based on an optimal control theory in which a performance function
of the fluid force is introduced. The performance function should be
minimized satisfying the state equation. This problem can be transformed
into the minimization problem without constraint conditions
by using the adjoint equation with adjoint variables corresponding to
the state equation. The performance function is defined by the drag
and lift forces acting on the body. The weighted gradient method
is applied as a minimization technique, the Galerkin finite element
method is used as a spatial discretization and the four-step explicit
scheme is used as a temporal discretization to solve the state equation
and the adjoint equation. As the interpolation, the orthogonal basis
bubble function for velocity and the linear function for pressure
are employed. In case that the orthogonal basis bubble function is
used, the mass matrix can be diagonalized without any artificial
centralization. The shape optimization is performed by the presented
method.
Abstract: In this study rack systems that are structural storage
units of warehouses have been analyzed as structural with Finite
Element Method (FEA). Each cell of discussed rack system storages
pallets which have from 800 kg to 1000 kg weights and
0.80x1.15x1.50 m dimensions. Under this load, total deformations
and equivalent stresses of structural elements and principal stresses,
tensile stresses and shear stresses of connection elements have been
analyzed. The results of analyses have been evaluated according to
resistance limits of structural and connection elements. Obtained
results have been presented as visual and magnitude.
Abstract: Development of motor car safety devices has reduced
fatality rates in car accidents. Yet despite this increase in car safety,
neck injuries resulting from rear impact collisions, particularly at low
speed, remain a primary concern. In this study, FEA(Finite Element
Analysis) of seat was performed to evaluate neck injuries in rear
impact. And the FEA result was verified by comparison with the actual
test results. The dummy used in FE model and actual test is BioRID II
which is regarded suitable for rear impact collision analysis. A
threshold of the BioRID II neck injury indicators was also proposed to
upgrade seat performance in order to reduce whiplash injury. To
optimize the seat for a low-speed rear impact collision, a method was
proposed, which is multi-objective optimization idea using DOE
(Design of Experiments) results.
Abstract: In this paper effect of stator slots structure and
switching angle on a cylindrical single-phase brushless direct current
motor (BLDC) is analyzed. BLDC motor with three different
structures for stator slots is designed by using RMxprt software and
efficiency of BLDC motor for different structures in full-load
condition has been presented. Then the BLDC motor in different
conditions by using Maxwell 3D software is designed and with finite
element method is analyzed electromagnetically. At the end with the
use of MATLAB software influence of switching angle on motor
performance investigated and optimal angle has been determined.
The results indicate that with correct choosing of stator slots structure
and switching angle, maximum efficiency can be found.