# Tapered Beam Snap Fit

#1

So basically what I have done here is, I tried to validate the Hand Calculations of a tapered Snap Fit Hook provided in this Plastic Snap Joints for Plastics by Bayer Material Science [1], by using SimScale FEA solver MUMPS.

## Physical Problem:

Given:
a. Material = Makrolon® polycarbonate
b. Length (1) = 19 mm (0.75 in)
c. Width (b) = 9.5 mm (0.37 in)
d. Undercut (y) = 2.4 mm (0.094 in)
e. Angle of inclination (a) = 30°

Find:
a. Thickness h at which full deflection y will
cause a strain of one-half the permissible
strain.
b. Deflection force P
c. Mating force W

## Meshes

Geometry was meshed in SimScale using the tet-dominant mesh. Added Mesh Refinement in areas of contact and other required once as per results.

## Simulations

Simulation Setup used is Static Analysis with nonlinearity set to True. By providing physical contact between two bodies block and snap.
Providing Master surfaces as:

And Slave Surfaces as:

Displacement boundary condition provided in the X direction as 0.016*t.

For the simulation setup, a fixed boundary condition was applied to the small box against which the body deforms.

And symmetry condition on the shown surface to decrease computational time and load over solver.

## Encountered Results:

Mating Forces (W in Paper) : 28.34*2= 56.68N

Deflection Force(P in Paper) = 16.1*2 = 32.2004N

Results almost match the hand calculated data.

[1] Plastic Snap Fit Design, http://fab.cba.mit.edu/classes/S62.12/people/vernelle.noel/Plastic_Snap_fit_design.pdf

[2] Smarter Snap-Fit Design using FEA, Webinar recording, https://www.simscale.com/snap-fit-design-using-fea/

'Buckle Analysis 2' simulation project by rlazaro
#2

A post was merged into an existing topic: ‘Snapfit’ simulation project by ojagtap

#3