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Title: A
study of the simulation of a front-crash-induced rollover crash
Author(s): C. Jiang, C.E. Neal-Sturgess
Source: Proceedings of the I Mech E Part D Journal
of Automobile Engineering
Volume: 221 part 12, pages 1487-1497, Dec 2007
DOI: 10.1243/09544070JAUTO628
Publisher: Professional Engineering Publishing
Abstract: Computer-based simulation of rollover
using MADYMO can assist in understanding the occupant and vehicle
kinematics of these complex long-duration events, and the resulting
occupant injuries. This study focused on the simulation of a front-crash-induced
rollover event. A hybrid finite element (FE)-rigid body model of
the vehicle was created to simulate the deformation during the impact
and its influence on the following rollover event. This was used,
together with a multi-body MADYMO model of a Hybrid III dummy, to
evaluate the probability of head injury in the crash. Special attention
was paid to the modelling of the suspension and tyres. Simulation
results from both the FE model and the rigid body model were validated
and evaluated. The results indicate that rollover simulations using
MADYMO proved to be an efficient computer aided engineering (CAE)
methodology. It is necessary to have a deformable FE front end for
the vehicle to simulate this type of event accurately. The injury
parameters from the simulation correlate well with the injury results
from the crash report.
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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.
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Title: A
hybrid method for feature recognition in computer-aided design models
Author(s): S S Dimov, E B Brousseau, R Setchi
Source: Proceedings of the I MECH E Part B Journal of Engineering
Manufacture
Volume: 221 No 1 Page: 79-96. Jan 2007
DOI: 10.1243/09544054JEM437
Publisher: Professional Engineering Publishing
Abstract: Automatic feature recognition (AFR) techniques
applied to three-dimensional (3D) solid models are an important
tool for achieving a true integration of computer-aided design (CAD)
and computer-aided manufacturing (CAM) processes. In particular,
AFR systems allow the identification in CAD models of high-level
geometrical entities: features that are semantically significant
for manufacturing operations. However, the recognition performances
of most of the existing AFR systems are limited to the requirements
of specific manufacturing applications. This paper presents a new
hybrid method that facilitates the deployment of AFR systems in
different application domains. In particular, the method includes
two main processing stages: learning and feature recognition. During
the learning stage, knowledge acquisition techniques are applied
for generating feature-recognition rules and feature hints automatically
from training data. Then, these hints and rule bases are utilized
in the feature-recognition stage to analyse boundary representation
(B-Rep) part models and identify their feature-based internal structure.
The proposed AFR method is implemented within a prototype feature-recognition
system and its capabilities are verified on two benchmarking parts.
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Title: Development
of CAD models from sketches: a case study for automotive applications
Author(s): R Vignesh, R Suganthan,
K Prakasan
Source: Proceedings of the I MECH E Part D Journal of Automobile
Engineering
Volume: 221 No 1 Page: 41-47. Jan 2007
DOI: 10.1243/09544070JAUTO331
Publisher: Professional Engineering Publishing
Abstract: Today products are designed not only for their
functional requirements but also for aesthetics. In the automotive
industries, styling has become a major part of the design process
with class-A surfaces. Class-A surfaces are freeform surfaces with
a continuous curvature. The process of engineering any component
or system begins by generating a concept that actually describes
the product in terms of its form, function, and fit. Concept sketches
help the designers to arrive quickly and easily at a stage where
a satisfactory design can be specified for detailed design. These
concept sketches can be used for development of the digital concept
design and analysis of the curves and surfaces. Software such as
Alias exists and thus can be used with suitable hardware for sketching
the concept of the car body on a computer screen. In this paper
a systematic procedure is discussed for generating class-A surfaces
from the images of concept sketches which are manually prepared
on paper. These images are imported into the sketch tracer module
of CATIA V5. A designer can use the image as the reference and produce
a digital sketch by tracing the image using CATIA V5 software without
adding any special hardware. Later, interrogation of these surfaces
for improved aesthetics can be attempted. This method will be useful
for the users of CATIA V5 to improve their design practices and
skills.
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Title: Robust
Design of an Automobile Front Bumper Using Design of Experiments
Author(s): Kwon-Hee Lee, Il-Kwon Bang
Source: Proceedings of the I MECH E Part D Journal of Automobile
Engineering
Volume: 220 Page: 1199-1207. Sept 2006
DOI: 10.1243/09544070JAUTO311
Publisher: Professional Engineering Publishing
Abstract: Bumpers are structural components installed to
reduce physical damage to the front and rear ends of a passenger
motor vehicle from low-speed collisions. Damage and protection assessments
are the commonly used design criteria in bumper design. For damage
assessment, the relative displacements representing stiffness performance
are defined and examined. At the protodesign stage for a new car,
finite element (FE) analysis is often utilized to predict the stiffness
of a bumper. However, conventional bumper analysis through FEM outputs
a constant stiffness even though the stiffness has some distribution
due to uncertainties. In this research, the uncertainties are assumed
to be the tolerances of thicknesses. Under this uncertain condition,
the displacements representing stiffness are calculated by approximate
statistics and by worst-case analysis. Then, a robust design is
determined by design of experiments (DOE) using the orthogonal array
strategy to find the design having a minimum weight of bumper within
the stiffness constraints. In this research, the thicknesses of
the inner beam, outer beam, and stay are treated as design variables.
The robust design procedure for a bumper, considering the uncertain
thicknesses, is presented.
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Title: Aerodynamics
of a wing in ground effect in generic racing car wake flows
Author(s): M D Soso, P A Wilson
Source: Proceedings of the I MECH E Part D Journal of Automobile
Engineering
Volume: 220 Page: 1-13. Jan 2006
DOI: 10.1243/095440705X69632
Publisher: Professional Engineering Publishing
Abstract: In an effort to provide more detailed insight
into the aerodynamic factors that may influence the creation of
overtaking opportunities in modern open-wheeled racing series, a
set of wind tunnel experiments was initiated in the moving ground
facilities at the University of Southampton. To generate data typical
of one car following another, a single-element wing in ground effect
was tested downstream of a bluff body that incorporated a diffuser
and rear wing. The tests included variations in the height and angle
of attack of the wing, while data collection was achieved via force
and pressure measurements, flow visualization and flowfield surveys.
The results were then compared with baseline data that were obtained
without the presence of the bluff body. It was found that, while
behind the upstream body, the wing experienced a decrease in its
downforce values, with the amount of downforce lost depending on
its height above the ground. It was also shown that more downforce
was lost from sections closer to the mid-span of the wing than was
the case from sections closer to the tips of the wing. |
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Title: Effect
of moving surface on the aerodynamic drag of road vehicles
Author(s): S N Singh; L Rai; P Puri; A Bhatnagar
Source: Proceedings of the I MECH E Part D Journal of Automobile
Engineering
Volume: 219 Page: 127 - 134. Feb 2005
DOI: 10.1243/095440705X5886
Publisher: Professional Engineering Publishing
Abstract: The effect on aerodynamic drag using a model
of a truck has been investigated by controlling the boundary layer
separation by the momentum injection method using a rotating cylinder.
It involves the use of experiments coupled with computational fluid
dynamics (CFD) analysis to validate the theory of momentum injection.
Modelling of the truck has been done on the software GAMBIT©
. The best suitable turbulence model was selected by comparing the
results with the experimental results. The rotational speed and
radius of the cylinder are varied to establish the effect of momentum
injection on aerodynamic drag. The coefficient of drag reduces by
approximately 35 per cent from an initial value of 0.5-0.32 for
a cylinder of radius 1 cm with rotational speed of 4000 r/min. |
Title: An experimental study of low-frequency motion in cars
Author(s): M J Griffin; M M Newman
Source: Proceedings of the I MECH E Part D Journal of Automobile Engineering
Volume: 218 Page: 1231 - 1238. Oct 2004
DOI: 10.1243/0954407042580093
Publisher: Professional Engineering Publishing
Abstract: Low-frequency acceleration can cause discomfort, instability and motion sickness, but there is little published information on this type of motion in cars. Accelerations in the fore-and-aft, lateral and vertical directions were measured continuously while driving around a fixed suburban route for 30 min. In separate studies, the variations in accelerations with the same driver driving the same car, the same driver driving different cars, and different drivers driving the same car were determined. The spectra of fore-and-aft and lateral accelerations were similar over the frequency range 0.1-0.5 Hz and, in consequence, motion sickness dose values (MSDVs) were similar in these axes when calculated using the frequency weighting in current standards. At frequencies less than 0.1 Hz, fore-and-aft acceleration was greater than lateral acceleration. The MSDVs for vertical acceleration were appreciably less than those for fore-and-aft and lateral acceleration. Acceleration in the vertical direction was predominantly influenced by vehicle suspension dynamics, with peaks between 1.0 and 2.0 Hz, and the differences between vehicles were greater than the differences between drivers. The fore-and-aft and lateral acceleration (as reflected in the MSDVs) showed differences between drivers that were greater than the differences between vehicles. Although such low-frequency fore-and-aft and lateral acceleration in cars is dependent on the behaviour of the drivers, some human responses to these motions may be modified by vehicle design.
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Title: An experimental study of low-frequency motion in cars
Author(s): M J Griffin; M M Newman
Source: Proceedings of the I MECH E Part D Journal of Automobile Engineering
Volume: 218 Page: 1231 - 1238. Oct 2004
DOI: 10.1243/0954407042580093
Publisher: Professional Engineering Publishing
Abstract: Low-frequency acceleration can cause discomfort, instability and motion sickness, but there is little published information on this type of motion in cars. Accelerations in the fore-and-aft, lateral and vertical directions were measured continuously while driving around a fixed suburban route for 30 min. In separate studies, the variations in accelerations with the same driver driving the same car, the same driver driving different cars, and different drivers driving the same car were determined. The spectra of fore-and-aft and lateral accelerations were similar over the frequency range 0.1-0.5 Hz and, in consequence, motion sickness dose values (MSDVs) were similar in these axes when calculated using the frequency weighting in current standards. At frequencies less than 0.1 Hz, fore-and-aft acceleration was greater than lateral acceleration. The MSDVs for vertical acceleration were appreciably less than those for fore-and-aft and lateral acceleration. Acceleration in the vertical direction was predominantly influenced by vehicle suspension dynamics, with peaks between 1.0 and 2.0 Hz, and the differences between vehicles were greater than the differences between drivers. The fore-and-aft and lateral acceleration (as reflected in the MSDVs) showed differences between drivers that were greater than the differences between vehicles. Although such low-frequency fore-and-aft and lateral acceleration in cars is dependent on the behaviour of the drivers, some human responses to these motions may be modified by vehicle design.
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