The document describes a study to develop accelerated durability tests for commercial vehicle suspension components. The objective is to design tests that reproduce expected fatigue damage and failure modes in a compressed time frame. Researchers collected field data on suspension loads from vehicle testing on different road surfaces. They analyzed the load data to create load spectra characterizing expected usage. An optimization approach was used to determine a proving ground test schedule that best matches the target load spectra, reproducing the expected fatigue damage in less time than real-world usage. The goal is to accelerate durability testing while still representing actual customer duty cycles and failure modes.
•SAE Baja is an Inter-colligate off road racing competition where the top engineering colleges in India successfully fabricate and race there all-terrain vehicles.
•The competition has various automotive giants like Mahindra, General motors etc. powering the event.
•The contest challenges each team to function as a firm whose objective is to design, fabricate, market and race off their vehicles that would be evaluated on a variety of manufacturing angles by various professionals from the sponsoring automotive companies.
•SAE Baja is an Inter-colligate off road racing competition where the top engineering colleges in India successfully fabricate and race there all-terrain vehicles.
•The competition has various automotive giants like Mahindra, General motors etc. powering the event.
•The contest challenges each team to function as a firm whose objective is to design, fabricate, market and race off their vehicles that would be evaluated on a variety of manufacturing angles by various professionals from the sponsoring automotive companies.
The Baja SAE Series is an annual competition organized by the Society of Automotive Engineers and has the objective to encourage undergraduate students to design, manufacture and test and All-Terrain vehicle prototype. There are almost 100 participants and it was a good opportunity to put in practice the knowledge acquired in class. In 2010 we achieved the 1st place in design, it has been the highest achievement in the whole team’s history, and it was of course a consequence of our hard work. As Powertrain head I led several tests in order to characterize the dynamical behavior of the vehicle, these developments settles a good base for future generations.
A Continuous Variable Transmission (CVT) is a common transmission system used in low power engines as in ATV or motorcycles. This system is also used by the Baja SAE USB vehicles prototypes and motivated by the willingness to improve the performance of the prototype; I developed a final degree project which aims to describe the dynamic behavior of this system. The result was an algorithm that simulates the dynamic behavior of the vehicle given certain parameters. This project was to opt for mechanical engineering degree, earning an honorable distinction for it.
Design analysis of the roll cage for all terrain vehicleeSAT Journals
Abstract We have tried to design an all terrain vehicle that meets international standards and is also cost effective at the same time. We have focused on every point of roll cage to improve the performance of vehicle without failure of roll cage. We began the task of designing by conducting extensive research of ATV roll cage through finite element analysis. A roll cage is a skeleton of an ATV. The roll cage not only forms the structural base but also a 3-D shell surrounding the occupant which protects the occupant in case of impact and roll over incidents. The roll cage also adds to the aesthetics of a vehicle. The design and development comprises of material selection, chassis and frame design, cross section determination, determining strength requirements of roll cage, stress analysis and simulations to test the ATV against failure. Keywords: Roll cage, material, finite element analysis, strength
All Terrain Vehicle specifications and analysis for VIRTUAL BAJA SAE 2016 India. The report is prepared by students of Mechanical Engineering from Tezpur University
Simulation and Static Analysis of an Off-Road Vehicle Roll CageIJMER
The SAE-BAJA competition is arranged every year with a purpose to have teams of
engineering students design, build and race a prototype of a four-wheel, one passenger, off-road
vehicle. The most important aspect of the vehicle design is the frame. The frame contains the operator,
engine, brake system, fuel system and steering mechanism, it must be of adequate strength to protect
the operator in the event of a rollover or impact. The roll cage must be constructed of steel tubing, with
minimum dimensional and strength requirements dictated by Society of Automotive Engineers (SAE).
Increased concern about the roll cage has created the importance of simulation and analysis thereby
predicting failure modes of the frame. In the present paper, we have used ANSYS to investigate the
response of the frame under various impacts. We considered a direct frontal impact and side impact
that results in a 4g horizontal loading, a rollover impact of 3g deceleration value, bump impact and
front torsional impact analysis with 3g deceleration value. The impact loading is simulated by
restricting displacements at certain locations, and applying discrete forces at various points on the
frame where the weight is concentrated. Throughout the analysis of roll cage more emphasis was given
on obtaining a allowable factor of safety and designed according to it.
The Baja SAE Series is an annual competition organized by the Society of Automotive Engineers and has the objective to encourage undergraduate students to design, manufacture and test and All-Terrain vehicle prototype. There are almost 100 participants and it was a good opportunity to put in practice the knowledge acquired in class. In 2010 we achieved the 1st place in design, it has been the highest achievement in the whole team’s history, and it was of course a consequence of our hard work. As Powertrain head I led several tests in order to characterize the dynamical behavior of the vehicle, these developments settles a good base for future generations.
A Continuous Variable Transmission (CVT) is a common transmission system used in low power engines as in ATV or motorcycles. This system is also used by the Baja SAE USB vehicles prototypes and motivated by the willingness to improve the performance of the prototype; I developed a final degree project which aims to describe the dynamic behavior of this system. The result was an algorithm that simulates the dynamic behavior of the vehicle given certain parameters. This project was to opt for mechanical engineering degree, earning an honorable distinction for it.
Design analysis of the roll cage for all terrain vehicleeSAT Journals
Abstract We have tried to design an all terrain vehicle that meets international standards and is also cost effective at the same time. We have focused on every point of roll cage to improve the performance of vehicle without failure of roll cage. We began the task of designing by conducting extensive research of ATV roll cage through finite element analysis. A roll cage is a skeleton of an ATV. The roll cage not only forms the structural base but also a 3-D shell surrounding the occupant which protects the occupant in case of impact and roll over incidents. The roll cage also adds to the aesthetics of a vehicle. The design and development comprises of material selection, chassis and frame design, cross section determination, determining strength requirements of roll cage, stress analysis and simulations to test the ATV against failure. Keywords: Roll cage, material, finite element analysis, strength
All Terrain Vehicle specifications and analysis for VIRTUAL BAJA SAE 2016 India. The report is prepared by students of Mechanical Engineering from Tezpur University
Simulation and Static Analysis of an Off-Road Vehicle Roll CageIJMER
The SAE-BAJA competition is arranged every year with a purpose to have teams of
engineering students design, build and race a prototype of a four-wheel, one passenger, off-road
vehicle. The most important aspect of the vehicle design is the frame. The frame contains the operator,
engine, brake system, fuel system and steering mechanism, it must be of adequate strength to protect
the operator in the event of a rollover or impact. The roll cage must be constructed of steel tubing, with
minimum dimensional and strength requirements dictated by Society of Automotive Engineers (SAE).
Increased concern about the roll cage has created the importance of simulation and analysis thereby
predicting failure modes of the frame. In the present paper, we have used ANSYS to investigate the
response of the frame under various impacts. We considered a direct frontal impact and side impact
that results in a 4g horizontal loading, a rollover impact of 3g deceleration value, bump impact and
front torsional impact analysis with 3g deceleration value. The impact loading is simulated by
restricting displacements at certain locations, and applying discrete forces at various points on the
frame where the weight is concentrated. Throughout the analysis of roll cage more emphasis was given
on obtaining a allowable factor of safety and designed according to it.
Lo que 3000 personas dicen sobre lo que dijeron 30.
Las charlas de TEDx Río de la Plata no son sólo una serie de monólogos inspiradores. Son una conversación que se inicia con los oradores y que luego se extiende por todo el mundo través tuyo y a través de miles de otras personas más.
La Charla de la Charla es un libro del Banco Hipotecario que intenta reflejar todo esa conversación: tweets y comentarios que analizan, interpretan, critican o simplemente reproducen lo que se dijo durante los dos días que duró el evento TEDx Río de la Plata.
Line balancing aims at grouping the facilities or workers in an efficient pattern in order to obtain an optimum or most efficient balance of the capacities and flows of the production or assembly processes.
The Company manufactures and supplies Engine & Chassis Dynamometerswith all Accessories and undertakes turnkey projects for the complete set-up of Engine Test Facility which includes Acoustic Enclosures, Water Circulation System with Cooling Tower, Engine Flue Gas Extraction System, Air Handling System and fully automated Engine Test System with match-plates, engine mounting pallets/trolleys with auto docking and Computer controlled Engine Performance Monitor.
The Company provides Engine Test Facility for carrying out endurance testing of engines. Two numbers of engine test beds with EDA&CSS have been erected in a separate premises of about 4000 sq. ft. area in the factory premises.
This presentation is on the based on case study done by using line balancing technique which a prime concern for an industrial engineer. This shows an efficient line balancing for a better production line performed at Runner Automobiles Ltd, Bangladesh.
Detection of Gear Fault Using Vibration AnalysisIJRES Journal
To achieve reliable and cost effective diagnosis, Motor current signature analysis is used to investigate the use of an induction motor as a transducer to indicate the faults in multistage gearbox via analyzing supply parameters such as phase current and instantaneous power. In gearboxes, load fluctuations on the gearbox and gear defects are two major sources of vibration. Further at times, measurement of vibration in the gearbox is not easy because of the inaccessibility in mounting the vibration transducers. This analysis system can be used for measuring the characteristics for a perfectly working gearbox and use the data as a standard for measuring faults and defects in other gearboxes. The objective of this paper is to design and diagnose fault in the gearbox using motor current analysis system at different gear operations on different loads. Steady load conditions on the gearbox are tested for current signatures during different gear operations. Also found the minimum power required to run on different gears and gear ratio. The motor current analysis system can be used further to specify mainly faults in the gear, misalignment of meshed gears, loss of contact of the gears and bearing wear.
1. 1
SAE Commercial Vehicle Engineering Conference
November 1-3, 2005
Development of AcceleratedDevelopment of Accelerated
Durability Tests for CommercialDurability Tests for Commercial
Vehicle Suspension ComponentsVehicle Suspension Components
R. Ledesma, L. Jenaway, Y. Wang, S. ShihR. Ledesma, L. Jenaway, Y. Wang, S. Shih
Advanced EngineeringAdvanced Engineering
Commercial Vehicle SystemsCommercial Vehicle Systems
2. 2
SAE Commercial Vehicle Engineering Conference
November 1-3, 2005
ObjectiveObjective
• The objective of this study is to design accelerated
durability tests for the components of a commercial
vehicle suspension system
• Requirements for the durability test:
• should have a well-defined correlation with customer usage
• accelerated in order to reproduce the desired amount of fatigue
damage in a reasonable amount of time
• must be able to reproduce failure modes that are expected in
the field
3. 3
SAE Commercial Vehicle Engineering Conference
November 1-3, 2005
StrategyStrategy
• Development of spindle load spectra for a targeted
customer usage, based on a limited set of field data
• Development of a proving ground testing schedule,
based on a given set of proving ground events, that
results in a well-defined correlation of spindle load
spectra, between the targeted customer duty cycle and
the proving grounds
• Development of a multi-axis, accelerated durability test
in the laboratory that simulates the proving ground tests
in a compressed time frame, while at the same time
duplicating the failure modes observed at the proving
grounds
4. 4
SAE Commercial Vehicle Engineering Conference
November 1-3, 2005
Duty Cycle DeterminationDuty Cycle Determination
• For accelerated durability testing purposes, the
product’s duty profile is a function of three variables
• roughness of the specific roads where the vehicle is anticipated
to operate
• the number of miles covered in the product’s warranty
• loading condition of the vehicle (percent of time the vehicle is
fully laden)
5. 5
SAE Commercial Vehicle Engineering Conference
November 1-3, 2005
Duty Cycle DeterminationDuty Cycle Determination
• Obtain a road profile classification map of the national highway
system from the Federal Highway Administration
• Assume that each road in the intended area of operation has an
equal chance of being traversed by the vehicle
• Example of vehicle service environment (road profiles) by vocation
National Interstate Midwestern StatesRoad Roughness
Classification % miles % miles
smooth roads 83 996,000 75 600,000
secondary paved roads 13 156,000 17 136,000
degraded paved roads 4 48,000 5 40,000
gravel/inner city roads 3 24,000
total service miles 1,200,000 800,000
% fully laden 65% 65%
6. 6
SAE Commercial Vehicle Engineering Conference
November 1-3, 2005
Mule Vehicle Data AcquisitionMule Vehicle Data Acquisition
• Drive a mule vehicle on public roads and measure
spindle loads that are representative for each type of
road surface
• Mule vehicle is operated under normal driving
conditions, usually following the allowable speed limits
• Also measure spindle loads corresponding to special
discrete events such as curb strikes, railroad crossings,
panic straight-line braking, braking while turning, and
parking lot steering
• For each measured public road event or discrete event,
perform rainflow counting on each of the spindle force
components (longitudinal, lateral, and vertical directions)
8. 8
SAE Commercial Vehicle Engineering Conference
November 1-3, 2005
Extrapolation of Rainflow MatricesExtrapolation of Rainflow Matrices
• After collecting samples of spindle load data for each type of road
surface, perform statistical extrapolation in order to generate
spindle loads that correspond to the required number of miles for
each type of road surface
-4
-2
0
2
4
-4
-2
0
2
400.511.52
rel.Häufigkeiten
kernel shape
11. 11
SAE Commercial Vehicle Engineering Conference
November 1-3, 2005
Proving Ground Test Schedule DeterminationProving Ground Test Schedule Determination
• The goal is to prescribe combinations of proving ground
segments and vehicle speeds such that the combination
of these proving ground events result in a good match
between the target rainflow matrices and the rainflow
matrices associated with the proving ground test, for all
of the spindle load channels
• An exercise in multi-objective optimization: how many
repeats of each of the candidate pairs of vehicle speed
and proving ground road segment will result in the best
match between the target rainflow matrices and proving
ground rainflow matrices?
12. 12
SAE Commercial Vehicle Engineering Conference
November 1-3, 2005
Proving Ground Test Schedule DeterminationProving Ground Test Schedule Determination
test track D
test track C
test track B
test track A
special test III
special test II
special test I
mixed trackΣ ? * track j
optimal
track mixing target
Select proving ground events
such that the target matrices
representing the customer duty
cycle are reproduced
Multidimensional
Optimization Problem
13. 13
SAE Commercial Vehicle Engineering Conference
November 1-3, 2005
Optimizing the PG Test ScheduleOptimizing the PG Test Schedule
• Partial pseudo-damage approach: approximating of the shape of
the rainflow histogram
• Take sub-matrices of the RFM into account (clusters)
• Consider not only the total damage, but also the shape of the RFM
ratio mixed track
over target
absolute values
clusters
Partial
Pseudo-
Damage
14. 14
SAE Commercial Vehicle Engineering Conference
November 1-3, 2005
Example: Optimized PG Test ScheduleExample: Optimized PG Test Schedule
• 7 out of 76 candidate PG events
can represent customer usage
• PG runtime: 1200 hrs (assuming
no downtime)
• All load channels accumulate 64-
137% of target pseudo-damage
Belgian Blocks
Gravel to Bumps
Forest
Altern. Bumps
Gravel
Altern. Bumps
A.Bumps to Emb. Rocks
Quality Check: Global Damage
15. 15
SAE Commercial Vehicle Engineering Conference
November 1-3, 2005
Comparison of Target and PG RainflowComparison of Target and PG Rainflow
MatricesMatrices
Quality Check: Shape of Rainflow Matrices
Good Agreement in Range Pair Histograms
16. 16
SAE Commercial Vehicle Engineering Conference
November 1-3, 2005
Accelerated Durability Rig Test ScheduleAccelerated Durability Rig Test Schedule
• The goal is to design a multi-axis, accelerated durability
test in the laboratory such that the test simulates the
proving ground tests in a compressed time frame, while
at the same time duplicating the failure modes observed
at the proving grounds
• Strategy: use time-domain fatigue editing techniques in
order to preserve the proper phasing between multiple
loads that act on the suspension system
• Construct a pseudo-damage time history associated
with each of the spindle load channels. The pseudo-
damage time histories are then lined up to identify time
intervals at which there is little pseudo-damage across
all spindle load channels
17. 17
SAE Commercial Vehicle Engineering Conference
November 1-3, 2005
Example: Multi-Axis Rig Test ScheduleExample: Multi-Axis Rig Test Schedule
• Reduce testing time by 60% relative to the proving ground test,
provided that the servo-hydraulic actuators have adequate capacity
• Retain 90% of the pseudo-damage associated with the original time
history
Method:Time-Domain Fatigue Editing:
The damage quotient of the 1. channel after filtering is 96.76
The damage quotient of the 3. channel after filtering is 98.94
The damage quotient of the 5. channel after filtering is 99.85
The damage quotient of the 2. channel after filtering is 99.47
The damage quotient of the 4. channel after filtering is 99.54
The damage quotient of the 6. channel after filtering is 99.44
29. direction has minimum damage quotient of 89.65
Original Signal
Fatigue-edited
Signal
18. 18
SAE Commercial Vehicle Engineering Conference
November 1-3, 2005
Accelerated Test Schedule: Range PairAccelerated Test Schedule: Range Pair
HistogramsHistograms
Fx
Fy
FzComparison between PG
and accelerated durability
rig test: high amplitude
cycles are kept 100%
19. 19
SAE Commercial Vehicle Engineering Conference
November 1-3, 2005
Accelerated Test Schedule: Frequency SpectraAccelerated Test Schedule: Frequency Spectra
Fx Fy
FzComparison between PG
and accelerated durability
rig test: frequency content
over 30 Hz is reduced
20. 20
SAE Commercial Vehicle Engineering Conference
November 1-3, 2005
Controlling the Multi-Axis RigControlling the Multi-Axis Rig
• Use RPC-Pro to control a multi-
input, multi-output nonlinear
system
• Requires an iterative process
• calculate the frequency
response of the test rig
• invert the frequency response
functions
• convolve the inverse FRF’s
with the desired response
signals
• predict a correction to the
inputs to minimize the error
between the desired response
and the actual response from
the test rig
21. 21
SAE Commercial Vehicle Engineering Conference
November 1-3, 2005
Simplified Single-Axis Component TestSimplified Single-Axis Component Test
• Possible only when the state of stress at the critical
locations can be considered as uni-axial state of stress,
and the geometry of the component results in stresses
at the critical locations that heavily depend only on one
input force component
• Single-axis rig test will address only one failure mode
• A series of single-axis rig tests can be performed on the
same test specimen in order to arrive at a
comprehensive design verification test that deals with
multiple failure modes
22. 22
SAE Commercial Vehicle Engineering Conference
November 1-3, 2005
Defining the Single-Axis ComponentDefining the Single-Axis Component
TestTest• Using multi-body dynamics, estimate the loads acting on the
component when the measured spindle loads are applied
• Perform a finite element stress analysis to obtain the time history of
strains and stresses in the component
• Perform a fatigue life prediction to determine the critical locations
and critical planes
• Identify the direction of the input force that will produce the specified
principal stress and critical plane orientation
• Perform a rainflow cycle counting of the resultant force, projected
along the critical direction
• Use the “cumulative exceedance plot” procedure to determine the
block cycle loading schedule for the single-axis rig test
23. 23
SAE Commercial Vehicle Engineering Conference
November 1-3, 2005
Example: Specification for a Single-Axis,Example: Specification for a Single-Axis,
Constant-Amplitude, Component DurabilityConstant-Amplitude, Component Durability
TestTest
• Equivalent vertical spindle load
• Mean value = 1.0G
• Alternating load = 0.6G
• Number of cycles: 132,000
LHS Spindle Vertical Force
0
1
2
3
4
5
0 2 4 6 8 10
Log of Cumulative Counts
LogofLoad
Amplitude
Field Duty Cycle Reference Load-Life Curve
Proving Ground Schedule
24. 24
SAE Commercial Vehicle Engineering Conference
November 1-3, 2005
ConclusionConclusion
• Customer usage profile was established, based on a
limited set of field data
• An optimized proving ground test schedule was derived
using commercial software
• Test schedules for the multi-axis, accelerated durability
rig test were determined, allowing us to simulate the
proving ground tests in a compressed time frame, while
at the same time duplicating the failure modes observed
at the proving grounds
• In some cases, simplified single-axis, single-component
tests can be developed