Bulb-Retainer Pull Out Force

[generaluday]

Hello,

I'm trying to compute the force required to pull out a bulb from it's retainer in a bulb-holder assembly.

The retainer has 2 clips, and as the bulb is pushed into it, the clips move outwards as the base of the bulb slides in the space between the clips, and then back inwards to snap into a groove in the bulb-base. I have to analytically compute the force required to yank the bulb out from this retainer. Does anyone have any ideas?

Also, just as a starting point, I did a non-linear static analysis with gap elements to determine the stresses in the retainer clips when they deform, i.e., move outward as the bulb is being shoved in. I used gap elements because the bases of the clips can only move by 0.1mm before they contact the inside wall of the bulb-holder, which is simulated by the gap elements. This is giving me a maximum stress (at the clip bases) of about 2700 MPa, which is way beyond the yield stress for spring steel (~1100 MPa).

A simple linear static analysis is indicating a much higher value of maximum stress. Assuming that this retainer is just a slight modification of their previous design(s), this doesn't make sense at all. What do you think?

Thanks!

 

[BlasMolero]

Dear Generaluday,
Definitely you will need to use Advanced Nonlinear Static module (SOL601,106) activating the LARGE DISPLACEMENTS EFFECT to solve this type of problems where sliding surface-to-surface contact is required to activate to account for contact between components.

You can prescribe an enforced displacement, or use nonlinear displacement control. After solving, check reactions, this is the force you will need to apply to pull out the part.

Best regards,
Blas.

~~~~~~~~~~~~~~~~~~~~~~
Blas Molero Hidalgo
Ingeniero Industrial
Director

IBERISA
48011 BILBAO (SPAIN)
WEB:

http://www.iberisa.com

 

[generaluday]

Thanks Blas! It worked. I appreciate your help.