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.