Optimization for Rear impact under section FMVSS-301. Performed analysis to avoid fueling spillage of 28g in the car model when impacted with a moving deformable barrier model. Performed optimization to reduced fuel spillage by 29%.

1. ME8020 CRASHWORTHINESS AND
OCCUPANT PROTECTION 1
FALL 2016
Project-3
REAR CRUSH - FMVSS 301
GUIDANCE PROFESSOR : BIJAN KHATIB SHADHIDI
SUBMITTED BY : KUNAL DAVE (GC3775)
PRATIK SAXENA (GD8959)

2. INTR0DUCTION
 FMVSS 301 - Fuel spillage in any fixed or moving barrier crash test
shall not exceed 28 g from impact until motion of the vehicle has
ceased, and shall not exceed a total of 142 g in the 5- minute period
following cessation of motion. For the subsequent 25-minute period,
fuel spillage during any 1 minute interval shall not exceed 28 g.
 FMVSS 301 – Impact speed while using rigid wall should be 35 mph
 FMVSS 301 - Impact speed while using Deformable barrier impact 50
mph
 We have used Moving Deformable barrier for our simulations.

3. MOVING DEFORMABLE BARRIER (MDB):
• MOVING DEFORMABLE BARRIER (MDB):For vehicles certified after September
1, 2006, or for early phase-in vehicles certified with the MDB, the contractor
shall provide a moving deformable barrier as specified in FMVSS214D (see
Figure 3) with exceptions to barrier height. A summary of MDB and honeycomb
face specifications are provided as follows:
• A. Total weight of MDB with impact face shall be 1,361 ± 4.5 kg (configured
MDB weight
• of 1,367.6 kg stated in P587.6(c).
• B. Overall length of MDB with impact face = 4,115 mm ± 25 mm
• C. Overall length of MDB excluding impact face = 3,632 mm (includes 50.8
mm thick
• mounting block)
• D. Overall width of framework carriage = 1,251 mm
• E. Tracking width (centreline to centreline of front or rear wheels) = 1,880
mm
• Our MDB weight is 3311.343 lb
• Velocity is 50 mph

4. FUEL PIPE CREATED
• Fuel Pipe was designed in Hypermesh
• It was then properly placed in vehicle to connect fuel tank with fuel cap using morphing technique in
Hypermesh software using Hypermorph.

5. Animation: Baseline

6. Animation: Plastic Strain
Without TyreBaseline With Tyre

7. Results: Back door Internal Energy
Without TyreBaseline With Tyre
The internal energy of back door increased when tyre was removed.
The reason is because tyre absorbs energy during rear crash.

8. Baseline Analysis
Force-Time curve
Total energy curve(Global) Internal energy curve(Global)
Displacement-Time curve

9. Baseline Analysis : Fuel spillage
Plastic Strain before impact Plastic Strain after impact
Volume of active parts = 0.00942179 m^3
= 2.488973 Gallons
= 10963.636 gm
Volume of active parts = 0.00941833 m^3
= 2.488059 Gallons
= 10959.613 gm
Fuel Spillage after deformation =4.023 gm

10. Optimization 1
• We supported fuel tank by structural shell plate under it.
• Material properties of Steel were given to support.
Plastic Strain before impact Plastic Strain after impact
Plate bent
Not so effective
Fuel Spillage after deformation = 5.307 gm : More spillage than baseline run

11. Optimization 2
• We morphed parts of rail to give a zig zag pattern
• It absorbed the energy comparatively more so that the deformation in the fuel tank is less.
Plastic Strain before impact Plastic Strain after impact
Fuel Spillage after deformation = 2.854 gm : Less spillage than baseline run

12. Optimization 2 Analysis
Force-Time curve
Total energy curve(Global) Internal energy curve(Global)
Displacement-Time curve

13. Description Max. Reaction
Force (N)
Effective Plastic
Strain
Internal Energy
(N-m)
Fuel Spillage
(grams)
Baseline Model 91509 0.415117 1.3689E+05 4.023
Optimization 2 94296 0.344596 1.3829E+05 2.854
Percentage
Improvement
Increased by
2.95%
Decreased by
16.98%
Increased by
1.01%
Decreased by
29.05%
COMPARISION

14. CONCLUSION
The volume spillage which we got in optimized file is 2.854 grams, which was decreased by
29 % as compared to baseline run.
The vehicle passed the FMVSS 301 criteria of Fuel integrity.
By changing the design of rails, there was significant reduction in fuel spillage since it
absorbed more energy and resulted in less Fuel tank deformation.
 We observed significant difference in internal energies of back door when tyre was present
or absent. It shows that tyre at the back door significantly reduces deformation during rear
crush.