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Publications
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To All Members of SAE F.D.& E.
Here is a proposal for a new FD&E research project. If you are interested and want a
piece of it, talk to Raj Thakkar, or others on the committee. ... or, just go do it. Have
fun too.
Objective:
To develop new correlated software that will allow engineers to measure the durability
of components of proposed vehicles by means of a "digital prototype" simulation.
General Plan:
Select an inexpensive, simple, existing vehicle that can be easily modeled with respect
to vehicle dynamics and component stress-strain behavior. Create a computer model of the
vehicle and "drive" it over a digital proving ground route. Test the actual
vehicle on the real course and measure the component loads, test the component durability,
and then compare the digital predictions with the test results. Assess where models need
to be improved and fix the deficient theory. After good correlation has been achieved, try
changing some components, through light weight material substitutions or material
processing changes, and then re-test and re-analyse for prove-out of the digital prototype
procedure.
Detailed Plans:
- Select "mule" vehicle: A $3500. 4x4 ATV vehicle has been selected for
purchase. The U.of Toledo has agreed to act as the home base site for vehicle
storage/teardown/build, subject to funding from SAE FD&E members. Presumably some
senior student design projects could also be "spun-off" from the overall
project.
If any other university would like to get involved heavily, and needs a vehicle or parts -
apply to SAE FD&E (thakkar.raj(at)towerautomotive.com )
- Digitze Vehicle Geometry points. Using a 3D spatial geometric digitizer,
determine the positions of all the connection points between all significant components.
Ford has volunteered to try this with vehicle no. 1.
- Measure Components Inertial Properties: after digitization, or possibly by using
vehicle No.2, tear down all components and determine their weights, center of gravities,
(moments of inertia?), and possibly some spring rates, bushing rates(?), shock damping
characteristics.
- Create Vehicle Model using ADAMS/DADS: using the geometry & properties of the
components, build the rigid body model. Check the model with some simple geometry test
track events.
- Create Loads Vehicle: Using strain gages and other transducers, create a loads
measurement vehicle. Sufficient channels should be selected to allow both the mearsurement
of vehicle simulation inputs, and also the correlation channels that are needed for
subsequent evaluation of the simulation. This is a non-trivial exercise. Advice from
experienced test people and vehicle modellers is critical. Mike Messman, Art Page, Dan
Morrow, Ric Mousseau, MTS, ...
- Measure the significant modes (e.g., bending and torsion modes below 50 Hz) of
vibration with experimental modal analysis of the ATV, with and without the suspension.
Spectral analysis of the experimental component load time history can determine if the
modes play a significant role in the dynamic response. The modal information can serve
both to correlate the vehicle dynamics model and to assemble a flexible body dynamics, if
needed. Possibly can be done by Brian Dabell & co at E.G.G.
- Measure Vehicle Loads: Record the time traces (min. 1000s/s/chan) as the vehicle
is driven over the "Proving Ground". Try a few simple events first - to give
some data to the vehicle modellers. Then iterate on transducers and record the complete
proving ground. Use the Somat proving ground surfaces. Possibly select another proving
ground and also record. Time base digital recordings are required.
- Rig Test in Lab From the recorded vehicle data develop a simulation test for the
full or partial sections of the vehicle. The test would allow a study in geater detail of
vibration/etc. behavior of all or parts of the vehicle. It is possible that Brian Dabell
at E.G.G. may be able to provide these tests to SAE F.D.& E. persons interested in the
project.
- FEA model of Components: Select components that are of interest to durability
analysts. Create FEA models. Use proving ground/or simulation load paths, and boundary
conditions. Perform unit load analyses for all loads and elements.
- Component Redesign and Material Substitutions: Redesign the geometries of
selected components and try some material subsitutions, such as PM steel, Cast Aluminum,
Cast Magnesium. Predict fatigue life of original(?) new components.
- Shot Peening : Select a component that is a good candidate for durability
improvements by shot peening (This could actually be done quite early in the project).
Prepare a peening procedure for the component and predict the life improvement. Test it
and see what happens.
- Lab Test new Components: Subject the components to simple and complex load
histories in the test lab.
- Check Prediction with Component Test: Compare fatigue results between simulation
and test.
- Re-measure Loads with new Components: Drive vehicle and record loads on the Somat
Parking lot proving grounds. Observe similarities and differences between orinal and new
component loads. Using strain gages, also observe "hot spot" fatigue areas
responses to load inputs.
- Evaluate Results: of test and predictions. Point out weak areas. If possible work
on improvements and try again.
Gleaned from above:
some potential student Projects:
(see also U.of I. (D.Socie) remarks in comments below).
Here are some tentative student type projects, should anyone be interested. They are
not necessarily in critical path order:
- Measure Vehicle geometry ..... Advisor: ?
- Measure Inertial properties of components. ... Adv.: ?
- Develop dynamics model ..... Advisor: Ric Mousseau
- Redesign and Shot Peen a component. ... Adv.: ?
- Measure Suspension Forces ..... Advisor: Dan Morrow
- Measure first 3 resonace modes ... Adv.: ?
- Develop simple suspension test....Adv. : ?
- Photoelastic coating work ..... Adv. : ?
- FEA analysis of component 1 ......Adv. : ?
- FEA analysis of component 2 ......Adv. : ?
- FEA analysis of component 3 ......Adv. : ?
- Evaluate different types of Weld analyses on a welded component. ...Adv. : ?
- Create a Web site to do display work and calculations and allow interactiver user
changes to loads/materials components, and compute new fatigue durability.
- Other ideas for such projects welcome.
Comments from Task Force Advisors:
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