6.1 Automotive
 (272KB)
Simulation
of wheel-rail damage 
Matthew Rudas, John Baynham, Robert A Adey
Wheel-Rail systems are inherently subject
to damage caused by the rolling contact and slip stick
behaviour between the wheel and the rail. Damage typically
manifests itself as wear or crack initiation and growth
in the rail. In order to accurately predict this phenomena
an accurate understanding of the contact mechanics and
crack behaviour is required. In this paper a methodology
based on BEM is presented which enables these type of
problems to be simulated. Two applications are presented.
In the first the wear of an auxiliary rail is predicted
and in the second the growth of a crack in the rail
due to the rolling contact is predicted.
(362KB)
Analysis
of a new concept in spline design for transmission output
shafts
Kin S. Yeung
The performance of an output shaft
can be improved by adding a taper in the axial direction
to its external spline. The optimal taper depends on
the design torque and the stress criterion. The largest
maximum principal stress in the shaft can be reduced
by as much as 15% if the spline is tapered 0.54o. This
type of reduction in stress would typically result in
greater than a factor of two improvement in fatigue
life. Conversely, it can be viewed as increasing the
maximum spline fatigue load by 15%.
(303KB)
New
computational and experimental stress analysis method
for the design decision of optimum piston configuration
of production engines
Hideo Okamoto, Nobou Anno, Tamotu Itoh
In response to new customer needs in
recent years, development efforts to car engines are
now being directed toward higher loads, speeds and through
the adoption of turbo chargers and other types of superchargers.
Requirements for a lower Emission (EM) and better fuel
Economy (FE) must also be satisfied in order to cope
with the environmental problems such as the greenhouse
effect and acid rain.
(424KB)
Stress
analysis of engine components using the Boundary Element
Method
Junichi Sugita, Tamotsu Itoh , IASCOME, Proc.
of BTEC 92, 1992.
Stress analysis through the Finite
Element Method (FEM) is widely utilized to design and
evaluate engine parts. However, it requires much rime
to produce models with complicated three-dimensional
profiles. There are also many cases in which it is difficult
to use the FEM system during the development stage.
We developed a new stress analysis system combining
the Boundary Element Method (BEM) with a pre/post-processor.
BEM is faster al producing models and is more flexible
in allowing for design modifications.
(492KB)
Engine
component design system using Boundary Element Method
J. Sugita, T. Itoh, T.Abe.
Analyses through the application of
the Finite Element Method (FEM) have been most widely
utilized for the design and evaluation of engine parts.
However, it requires a long time to produce models that
have complicated three-dimensional profiles. Due to
this disadvantage, it is difficult to use the FEM system
in developmental stages. We developed a new design system
combining the Boundary Element Method (BEM) with a pre/post-processor.
6.2
Aerospace
(1,479KB)
Impact
of the Boundary Element Method on engineering quality
and productivity
A. Wanderlingh
Two extremely important challenges
confronting the aerospace industry in the 1990’s,
and beyond, is its ability to produce high quality products
and, to deliver them to market rapidly. When one considers
the enormous global social changes taking place, such
as, the newly unified Europe in 1992, and the opening
up of the Eastern Bloc and Asian markets, the incentives
to the aerospace industry become quite clear. That is,
the companies that are the first, with the best, will
capture the largest market share.
(455KB)
BEASY
used for optimization of rotor stress
Paul R. Hearn
A stress analysis has been performed
on a ceramic vane pump rotor to determine cyclic life.
Ceramics were chosen for the rotor due to the corrosive
nature of the application as well as its good wear resistance.
Due to the brittle nature of the ceramics and the desire
to accurately predict cyclic life, determination of
the peak elastic stress was a major concern. Finite
element analysis, namely MSC/NASTRAN, was initially
chosen for the analysis.
(136KB)
The
appropriate use of boundary elements in the aircraft
gas turbine business
Gareth H. Richards
Boundary Element techniques have been
introduced at General Electric Aircraft Engines (GEAE)
to improve productivity In the analysis of a large class
of structural problems. This paper examines the business
reasons that motivated this introduction, stressing
the principle that the most appropriate analysis tool
should be selected for a given task. The practical obstacles
to achieving the maximum potential benefit from these
techniques are discussed.
(384KB)
Technical
Note: Comparison of boundary element and finite element
methods for linear stress analysis - technical program
results
A.I. Wanderlingh , Engineering Analysis, Vol
3, No. 3, 1986.
Over the years, engineering organisations
have become increasingly dedicated to improving productivity
through the use of high-speed computers, computer-aided
design and manufacturing (CAD/CAM) techniques and computer-analysis
methods such as the Finite Element Method. Despite the
analytical method's substantial impact on productivity,
three limiting factors persist: (1) the difficulty in
identifying connectivity errors, particularly in 3D
models, (2) the need to discretize the entire volume
of a structure, and (3) the density of the mesh needed
to obtain accurate surface stresses.
(137KB)
Fatigue
Crack Growth Simulation for Complex Three-dimensional
Geometry and Loading
Thomas J. Curtin, Robert A. Adey, John M.W. Baynham
and Philip Marais
The focus of this paper is on the implementation
of the boundary element method to investigate the impact
of cracks in aerospace components. The theoretical background
of the boundary element based fracture mechanics algorithms
is discussed and the capability of the method is illustrated
with applications pertinent to the aerospace industry.
The methodology and applications discussed in this paper
are based on the BEASY Fatigue and Crack Growth software
developed by BEASY The boundary element method utilized
in the software is well suited for simulating fracture
and crack propagation.
6.3
Biomedical
(237KB)
SULLA
VALUTAZIONE NUMERICA DELLE CONDIZIONI ELASTOSTATICHE
DI UN IMPIANTO DENTARIO ENDOSSEO
E. Armentani, F. Caputo jr., R. Citarella, R. Esposito,
M. Infante, G. Lavorgna
This work faces the numerical problems
related to the calculation of stress and strain distribution
induced by a dental implant in the surrounding mandibular
bone, by using parametric BEM and FEM on varius implant
shapes and biological conditions. This work, mainly
based on methodological aspect, highlights the opportunity
to get accurate assesment of the stress-strain results
on the bone implant interface, that is the most critical
area caused by the mastication forces.
(341KB)
Some
applications of Boundary Element Method in Biomedicine
C.A. Brebbia and J.M.W.Baynham
This paper describes some applications
of the Boundary Element Method (BEM) [1][2] to simulate
biomedical problems. The BEM has developed into a powerful
tool for engineering analysis, but most applications
of the new technique are in the fields of mechanical
and aerospace engineering. Other important cases are
for the study of electrical and fluid flow problems,
and the range of applications is extending from day
to day.
6.4
Electrical and Electronics
(361KB)
Use
of electric analogy for the determination of the soil
permeability from field tests
Lafhaj Z., Shahrour I. & Dauphin J.Y.
This paper is concerned with the evaluation
of the shape factor by means of the electric analogy.
This factor is used for the determination of the soil
permeability from field tests. After a description of
the experimental device, we present the methodology
followed for the determination of the shape factor.
Then, we study the influence, on this factor, of some
parameters such as the position of the infiltration
cavity in the soil layer and the presence of an obstacle
or of heterogeneity near the cavity.
(546KB)
Modelling
of permanent magnets with the Boundary Element method
R. Roeckelein, H.A.M. v.d. Berg, Engineering
Analysis with Boundary Elements, Vol, 7, No. 3, 1990.
When Boundary Element Methods are exploited
for the numerical calculation of linear magnetostatic
fields, a vector potential formulation is mostly applied
to deal with two-dimensional problems whereas scalar
potentials seem to be more suitable for three-dimensional
situations. This paper shows how permanent magnets can
be modelled in this environment. The source terms arising
from permanent magnets consist of a curl or divergence
of the magnetization depending upon the formulation.
(510KB)
Improvement
in thermal properties of multi-beam laser diode array
Setsuko Murata, Kazutoshi Nishimura, Proc. Int.
Symp. on Optical Memory, Japanese Journal of Applied
Physics, Vol. 28, Supplement 28-3, pp65-170, 1989.
Improvement in thermal performance of a high-density
laser diode array including mutual thermal interactions
is examined. Three-dimensional thermal analysis of a
50-micro-m-spaced 5-beam junction-down mounted laser
diode array is performed on a practically scaled model,
using the Boundary Element Method. The thermally dominant
components are the chip and submount. The dominant heat
flow route is also shown. A new structure is proposed
that combines a high thermal conductive submount, a
thin cap layer, and a heat-pass-wire, which acts as
a bypass.
(392KB)
A
simple new laser diode array model for thermal interaction
analysis
Setsuko Murata, Kazutoshi Nishimura , J Appl.
Phys. Vol. 70, No. 9, 1991.
A simple new laser diode array model
using the boundary element method is presented. This
model—which needs few boundary elements and little
calculation time-represents a multilayer chip as a single-layer
chip and distributed heat sources as a line heat source
in the center of an active region, and neglects the
grooves between array elements. For three types of laser
diode array chips with element spacing greater than
50-micro-m, the simple model estimates thermal interactions
to within 2%.
(543KB)
The
boundary element method for electromagnetic problems
C.A. Brebia, R. Magureanu, Engineering Analysis,
Vol. 4, No. 4, 1987.
The boundary element method has been
successfully applied to a variety of problems in engineering,
particularly to analyse thermal and elastostatics problems.
More recently the range of applications has been extended
considerably to cover a whole range of solid and fluid
mechanics problems. The main attraction of the method
is the simplicity of the data required to solve the
problem, as only the surface of the body needs to be
discretised.
(397KB)
Thermal
Analysis of solid-state devices using the Boundary Element
Method
Chin C. Lee, Arthur L. Palisoc, John M.W. Baynham,
IEEE Transactions on Electron devices, Vol. 35,
No. 7, 1988.
Thermal analysis of two-dimensional
and three-dimensional two-layer device structures have
been carried out using the boundary element method (BEM).
The resulting thermal profiles agree very well with
those obtained using analytical solutions. This agreement
indicates not only the accuracy of the BEM but also
the correct derivation of the analytical solutions.
6.5
Geomechanics and Geophysical
(170KB)
Modelling
Underground Mines for Rock Stability Assessment Using
Boundary Elements. A New Approach for Large Scale
Problems
Robert
A Adey, Andrea Calaon
The Boundary Element Method has been
applied to calculate stress distribution and stability
of underground mines for disposal of chemical waste.
A case similar to the Stripa mine in Sweden has been
considered. The rock mass was granite, with major fracture
zones represented by three families of planes mutually
orthogonal and 100 meters distant from each other. The
pre and post processor GiD [3] and the Boundary Element
software BEASY [2] have been used for model preparation,
solution and result post processing.
(1,572KB)
Three-dimensional
elastic earthquake modelling based on integrated seismological
and InSAR data: thhe Mw = 7.2 Nuweiba earthquake, gulf
of Elat/Aqaba 1995 November
The Nuweiba earthquake (1995 November 22; Mw = 7.2),
the largest seismic event along the Dead Sea Transform
(DST) in at least 160 yr, ruptured 45-50km along the
Aragonese segment of the left-stepping strike-slip fault
system occupying the gulf of Elat/Aqaba (southern segment
of the DST).
(2,079KB)
Three-dimensional
models of deformation near strike-slip faults
We use three-dimensional elastic models
to help guide the kinematic interpretation of crustal
deformation associated with strike-slip faults. Deformation
of the brittle upper crust in the vicinity of strike-slip
fault systems is modeled with the assumption that upper
crustal deformation is driven by the relative plate
motion in the upper mantle. The driving motion is represented
by displacement that is specified on the bottom.of a
15-km-thick elastic upper crust everywhere except in
a zone of finite width in the vicinity of the faults,
which we term the “shear zone.”
(333KB)
Scale
dependency in rock strength
R.A. Adey , R. Pusch, Engineering Geology, Vol
53, No. 25, 1999.
It has long been recognised that the
size of a rock sample can have a significant impact
on the strength recorded of the sample. In this paper
the scale dependence caused by the presence of larger
weaknesses when the sample volume increases is investigated.
An approach based on linear elastic fracture mechanics
is proposed to define the behaviour and results are
presented.
6.6
Microstructure and Microsystem
(253KB)
Mechanical
design simulation of microsystems and microstructures
R.A. Adey
This paper describes work being carried
out on the development of an integrated environment
for the analysis and simulation of microsystem and microstructure
devices, components and processes. The objective being
to shorten the time to design new products, reduce the
cost of development, increase quality and reliability
and finalise a product specification at the design stage
to eliminate the need for expensive prototypes.
6.7
Fluid Sloshing
(354KB)
Analysis
of fluid structure interaction of spacecraft's fluid
tanks using Combined Boundary Element and Finite Element
Methods
S.M. Niku, R.A. Adey, M. Klein, W. Taicher, M. Fries
, Proc, Internat. Conf.: Spacecraft Structures and
Mechanical Testing, Noordwijk, The Netherlands, 1991.
The fluid tanks play an important role
in the dynamic behaviour of spacecraft as they carry
fuels which may take up to 50% of the total spacecraft
mass. The fluid tanks are therefore needed to be adequately
modeled in order to obtain an accurate prediction of
spacecraft dynamic behaviour. This paper presents an
algorithm by which a Boundary Element and a Finite Element
systems are combined to solve the problems of fluid
- structure interaction of fluid tanks. The fluid is
assumed to be incompressible and motion limited to small
amplitudes.
(354KB)
Analysis
of the behavior of liquid filled tanks by Coupling Boundary
Element and Finite Element Methods
M. Klien, S.M. Niku, R.A. Adey, A. Kreis
In this work, the general purpose BEM
system BEASY has been coupled with the FEM system (ASKA).
The model is initially generated within a general modeller
like PATRAN which is capable of describing the whole
structure. The overall fluid's data is then extracted
automatically and passed to (BEASY) where the computations
of mass and stiffness matrices are carried out. The
BEM generated matrices representing the fluid are then
transformed and combined with those of the structure
obtained using BE analysis. The overall process is currently
compatible with the ASKA finite element system only
but could be easily extended to work with most general
purposes FE systems. |
