Solder Joints Modeling via FEA

[francesco87]

Hi everybody,
I need to simulate - with a satisfactory accuracy - the attachment between a PCB (Printed Circuit Board) and some electronic modules through a pin-in-hole solder connection (see picture attached).

I found plenty of articles about the so-called Global-local modelling technique, in which a coarse global model is used to simulate the whole assembly; the output displacements are then given as inputs to a fine local model representing the critical region of interest. Nevertheless, this technique is usually adopted for a slightly different kind of attachment ("Ball-grid-array"), and I was wondering whether it is suitable for my case or not.

Any tips? Thanks in advance.

 

[jedward]

Solder joints are complicated! especially if high rel is required

The primary question is to determine the environments in which they must function and survive. Consider mechanical and thermal requirements.

The mechanical requirements are generally not a problem since the components have little mass relative to the solder strength.
Flexing of the mounting substrate can be a significant issue since the stresses at the solder joints will be large when the substrate flexes. - see the treatment by Steinberg in Vibration Analysis in Electronic Equipment.

Thermal cycling induced stresses are more complicated because solders are generally much stronger at low temperatures but can "flow" or release strain at high temperatures - thus the reliability depends no only on the temperature changes but also the overall range of temperatures that are expected. PCBs have generally anisotropic thermal properties

Reliability of the joints also depends upon the shape of the leads since they provide stress relief - see nasa soldering requiring standards.

Mounting of more massive components such as transformers etc can prose significant problems in the more conventional mechanical environments of shock and vibration.

 

[KevinDeSmet]

I'm with Jed on the complication factor. Ask yourself, what does FEA like? You might answer.. predictability, consistency, perfectness or perhaps linearity. Now realize that welds are none of those things!

Certified SolidWorks Professional

 

[francesco87]

Thanks guys... actually I feel a little bit discouraged but I'll keep trying! What about replacing the soldered pins with some sort of "equvalent beams"? Would it work in your opinion?