Use Solidworks Simulation to estimate stress in a container partially filled with fluid.

1. Liquid sloshing in a partially filled
container
first order stress analysis
10/29/2016
Don Blanchet
3B Associates
dwb3298@verizon.net

2. Goal
 To estimate the structural adequacy of
a fluid filled Delrin plastic container.
 The actual behavior of the fluid is not
a priority.

3. Analysis
 Solid / Fluid interaction requires the
use of FEA and CFD or a Multiphysics
analysis simulation code.
 The accurate use of these techniques
requires the skills of an expert analyst
and considerable software licensing
cost.
 A method using only FEA is
demonstrated for a first order analysis
by a design engineer.

4. Reference sloshing analysis : nonlinear
computational fluid dynamics

5. From Reference: fluid waves
Not necessary
For container
Stress analysis

6. Method – utilize FEA not CFD
 Assign material properties to the
pseudo “fluid”
– Density of water
– Very small elastic modulus
– 0.495 Poisson’s ratio incompressible
– No penetration surfaces between the
“fluid” and the container walls
– Expected behavior like Jello

7. Model test case
Delrin container
½ inch thick
15 x 15 x 10.5

8. Model
“fluid” ¾ full

9. Transparent container

10. 1 G local gravity “fluid”
without container
Deformation -sagging block of Jello

11. Jello resonant frequencies
F1 = 5.0 hz

12. Jello resonant frequencies
F2 = 8.0 hz

13. Jello resonant frequencies
F3=9.0 hz

14. Sloshing frequency 11.2 hz

15. Sloshing frequency 12 hz

16. Worse case : Crash
loading 10G
Wave
Height
1 inch
Fixed at bosses
4 corners

17. Maximum Wall stress
2900 psi
Factor of safety = 5900/2900 = 2.03