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Solidworks Simulationdrop test studyShipping Box
07/29/2016 rev 1
Don Blanchet
3B Associates
dwb3298@outlook.com
Task
Perform an FEA drop test analysis on a proposed shipping container with payload.
Determine the peak acceleration and displacement from a drop height of 28 inches on to a hard surface.
Study various elastomer cushioning materials.
Solidworks 2015 - Simulation
Simplified model
Payload 70 lb
Shock absorber 8 places
Wooden box ½ inch plywood
Simplified model payload removed
21 x 15 x 12 inches
Meshed model top cover removed
Press fit corner shock absorbers
Drop flatOn bottom
surface
Shock absorber materials
material Elastic moduluspsi
DensityLb/cu-inch
ABS Polyurethane
440,000 .035
polyethylene 80,000 .031
Nitrile styrene20% glass filled
950,000 .039
Drop animation case removed
Deformation at impact40x scale
Deformation at impact40x scale
Deformation at impact40x scale
Deformation at impact40x scale
Absorbers are not bonded to the payload or case
Payload displacement at impact
0
0.01
0.02
0.03
0.04
0.05
0.06
0.07
0.08
0.09
aluminum glas styrene ABS Polyethylene
Deflection of Payload , inches
Shock acceleration time response during the first millisecond, G’s
-30000
-20000
-10000
0
10000
20000
30000
40000
aluminum glas styrene ABS polyethylene
Shock time response in the first millisecond
Best candidate polyethylene
-30000
-20000
-10000
0
10000
20000
30000
40000
aluminum polyethylene
Summary
As expected the shock absorber with the lowest modulus of elasticity provides the lowest payload shock response at impact.
The maximum deflection does not exceed 10% of the absorber thickness of 0.50 inches.
Performing an FFT on the shock time response will convert it to the frequency domain which can be used as an SRS for detailed payload stress analysis during the drop event.