|
|
|
Title: Analytical
prediction of springback based on residual differential strain during
sheet metal bending
Author(s): H K Yi, D W Kim, C J Van Tyne, Y H Moon
Source: Proceedings of the I Mech E Part C Journal
of Mechanical Engineering Science
Volume: 222 part 2, pages 117-129, Feb 2008
DOI: 10.1243/09544062JMES682
Publisher: Professional Engineering Publishing
Abstract: As the springback of sheet metal during
unloading may cause deviation from a desired shape, accurately predicting
springback is essential for the design of sheet stamping operations.
Finite-element models have not been successful in predicting springback;
hence there is a need for analytical models to make such predictions.
In this study, a model based on differential strains after relief
from the maximum bending stress is derived for six different deformation
patterns in order to predict springback analytically. The springback
for each deformation pattern is estimated by the residual differential
strains between outer and inner surfaces after elastic recovery.
Each of the six deformation patterns has a valid region of applicability,
based on elastic modulus, yield strength, applied tension, and bending
geometry. Analytical equations for the springback of the sheet deformed
under these six deformation patterns are derived. Traditional analytical
models for springback prediction have been based on elastic unloading
from a bending moment. Traditional models also require the knowledge
of the stress distribution through the thickness of the sheet, whereas
the residual differential strain model only requires the stress
state on the outer and inner surfaces of the sheet. In order to
compare the residual differential strain model with the traditional
bending moment model, a bending moment model is derived for the
same exact deformation patterns. Results from the two models are
compared for various materials.
|
| |
Title: Rapid
fabrication of metal-coated composite stereolithography parts
Author(s): Z Zhou, D Li, J Zeng, Z Zhang
Source: Proceedings of the I MECH E Part B Journal of Engineering
Manufacture
Volume: 221, No 9. September 2007
DOI: 10.1243/09544054JEM827
Pages: 1431-1440
Publisher: Professional Engineering Publishing
Abstract: In this paper, the rapid fabrication method based
on stereolithography (SL) and electrochemical deposition is described
in detail and mechanical test results of composite nickel-coated
SL parts are presented. Coatings of electrodeposited nickel on SL
prototypes result in increases in Young's modulus, UTS, flexural
modulus, and strength. Electrodeposited nickel coating has dramatically
improved the overall strength and stiffness of SL parts. The adhesive
strength of the roughened SL resin-nickel interface is higher than
the original. In particular, the influence of the surface roughness
on adhesive strength between SL and metal is investigated. Moreover,
this paper has presented an application of a structural electrodeposited
nickel coating over SL parts to make a functional airfoil model
with a complex internal structure and sufficient mechanical strength
and stiffness.
|
| |
Title: Simulation
of distortion induced in assemblies by spot welding
Author(s): X Fan, I Masters, R Roy, D Williams
Source: Proceedings of the I MECH E Part B Journal of Engineering
Manufacture
Volume: 221 Page: 1317-1326. August 2007
DOI: 10.1243/09544054JEM782
Publisher: Professional Engineering Publishing
Abstract: Maintaining dimensional tolerances during the
manufacture of vehicle bodies is important to the automotive sector.
With the industry's drive towards continuous improvement there is
increasing focus on the effect of the joining process on the final
assembly. A simulation tool that can predict the distortion resulting
from assembly offers potential time- and cost-savings throughout
design and manufacture. Although individual spot welds have been
studied in detail, to-date methods to predict the distortion of
a final assembly have concentrated on the variation of the constituent
components. In the current paper simulation is used to predict the
distortion of an assembly owing to spot welding using a local/global
approach where the local distortion occurring around a single spot
weld is projected onto a global assembly at each of the weld locations.
The comparisons of the simulations of the assemblies with coordinate
measuring machine (CMM) data under different clamping conditions
suggest sufficient agreement with experimental data to be of value
to engineers. A number of possible enhancements are suggested to
improve the accuracy of final shape prediction.
|
Title: The
opportunities for multimedia supported remote maintenance provided
by an implementation of a component-based system in the automotive
domain
Author(s): Min Huey Ong, A A West, Szer Ming Lee, R Harrison
Source: Proceedings of the I MECH E Part B Journal of Engineering
Manufacture
Volume: 221 Page: 787-798. May 2007
DOI: 10.1243/09544054JEM620
Publisher: Professional Engineering Publishing
Abstract: This paper describes an evaluation method for
assessing the effectiveness of using multimedia tools for remote
maintenance of production machinery in the automotive sector. The
multimedia tools have been developed to support the design implementation
and maintenance of a component-based control system for manufacturing
machines. Scenario testing has been adopted to assess the possible
benefits associated with the use of multimedia tools. It has been
found that the multimedia tools are effective in improving the diagnostic
capability of the maintenance provider in terms of acquiring better
information and reducing the time taken to diagnose the problems.
However, there are security, human resource restructuring, maintenance
agreement, and training issues associated with the service that
must be appreciated prior to large-scale adoption of the technology.
|
Title: Cost
forecasting model for order-based sheet metalworking
Author(s): A Bargelis, M Rimasauskas
Source: Proceedings of the I MECH E Part C Journal of Mechanical
Engineering Science
Volume: 221 Page: 55-65 - 211. January 2007
DOI: 10.1243/0954406JMES269
Publisher: Professional Engineering Publishing
Abstract: This paper deals with a cost forecasting model
for order-based sheet metalworking. The model has been developed
on the cost analysis performed by comparing traditional manufacture
of sheet metal parts (dies and presses) with rapid manufacture (RM)
as CNC punching, laser cutting, and bending in terms of the cost
per part unit made in various quantities. The findings show that
it is more economical to apply RM methods for some sheet metal design
geometries than traditional approaches in the production of thousand
units. The developed cost forecasting model has been tested and
adopted in two sheet metalworking companies. It furnishes the possibility
for producer to find quickly and to estimate the product cost at
an early stage of order-based sheet metalworking industry with satisfactory
accuracy. The proposed model is being implemented both in industry
and university education process.
|
Title: Computer
Simulation of Casting Process of Aluminium Wheels - A Case Study
Author(s): Yeh-Liang Hsu, Chia-Chieh Yu
Source: Proceedings of the I MECH E Part B Journal of Engineering
Manufacture
Volume: 220 Page: 203 - 211. February 2006
DOI: 10.1243/09544054JEM381
Publisher: Professional Engineering Publishing
Abstract: Aluminium disc wheels intended for normal use
in passenger cars are commonly produced by gravity casting. If the
cooling process and the initial temperature of the mould are not
well controlled, shrinkage cavity will occur after solidification,
causing leakage in the disc wheel. In this research, a casting simulation
software is used to simulate the casting process of aluminium wheels.
The casting simulation is done iteratively until the mould temperature
converges to a stable temperature. A 'shrinkage index' (SI) is defined
to provide a quantified index of casting quality of aluminium wheels,
based on the phenomenon of liquid entrapped at the joints of rim
and spokes of the wheel where shrinkage cavity usually happens.
This shrinkage index shows good correlation with the aluminium wheel
leakage test results. This paper also discusses the influence of
cooling process parameters on SI, including initial mould temperature,
and geometry of the wheel, which verifies engineers' empirical data.
This iterative simulation process and SI can be used to predict
the casting quality of aluminium wheels and to find the optimal
parameters of the casting process.
|
Title: Force
modelling of the crankshaft pin grinding process
Author(s): A. P. Walsh; B. Baliga; P. D. Hodgson
Source: Proceedings of the I MECH E Part D Journal of Automobile
Engineering
Volume: 218 Page: 219 - 227. March 2004
DOI: 10.1243/095440704322955768
Publisher: Professional Engineering Publishing
Abstract: A force model was developed for crankshaft pin
grinding to predict the forces generated during grinding. The force
model developed builds on the authors' previously developed model,
which predicted the out-of-roundness in crankshaft pin grinding.
The model includes key grinding variables, such as the work removal
parameter (WRP), system stiffness and Young's modulus to determine
the end forces produced. The model also includes the important geometrical
relationships that are unique to this type of grinding. The model
was verified using an experiential set-up involving sophisticated
strain gauge force measurements on a commercial Landis CP grinding
machine, with close correlation between the results and the model.
|
Title: Analysis
of residual stresses in main crankshaft bearings after induction
surface hardening and finish grinding
Author(s): J Grum
Source: Proceedings of the I MECH E Part D Journal of Automobile
Engineering
Volume: 217 Page: 173 - 182. March 2003
DOI: 10.1243/09544070360550282
Publisher: Professional Engineering Publishing
Abstract: The exact pattern of residual stresses will depend
on the heat treatment temperatures employed, the depth of hardening
and the type of quenchant. Process conditions that give rise to
compressive residual stresses on the surface of heat-treated components
are favourable. This type of residual stress delays the initiation
of fatigue cracking in service, which typically occurs on the surface
of the part under the action of cyclic tensile stresses. The last
phase in the manufacturing of crankshafts is finish grinding in
order to achieve the desirable condition of the surface and the
subsurface layer, i.e. suitable dimensions, suitable surface roughness
and the corresponding distribution of relative grinding residual
stress in the subsurface have to be ensured. By correct selection
of the grinding wheel and grinding conditions, taking into account
the physical and mechanical properties of the workpiece material,
the very favourable compressive residual stresses in the hardened
surface layer will be retained after grinding.
|
Title: A
fatigue design method for spot-welded lap joints
Author(s): Dongho Bae; Ilseon Sohn; Wonseok Jung; Sung-Jin
Song
Source: Proceedings of the I MECH E Part D Journal of Automobile
Engineering
Volume: 216 Page: 181 - 189. March 2002
DOI: 10.1243/0954407021529020
Publisher: Professional Engineering Publishing
Abstract: Recently, a new issue in the design of spot-welded
structures has been economical prediction of a fatigue design criterion
without additional fatigue tests. In general, the most typical and
traditional method is the use of a ?P - Nf curve. However, since
the fatigue data on the curve vary according to welding conditions,
materials, geometry and fatigue loading conditions, it is necessary
to perform an additional fatigue test in order to determine a new
fatigue design criterion for a spotwelded lap joint of different
dimensions and geometry. This is, of course, a very time consuming
and costly task. Thus, in this paper, an economical and advanced
design method is proposed, the reliability and performance of which
have been verified with the theory of the Weibull probability distribution.
As a mechanical parameter to predict the fatigue design criterion,
a maximum stress equation has been defined using artificial neural
networks. By using the maximum stress equation and the fatigue data
previously obtained from fatigue tests, a reasonable fatigue design
criterion for a spot-welded lap joint could be predicted without
any additional fatigue tests. The results predicted by this method
showed very good agreement with actual fatigue data.
|
|
 |
|
