Bonding Analysis

[Lee.Conti]

Hi,

Wonder how do you perform adhesive analysis or simulation?

Do you just pick up the stresses from the FEM and compare against the adhesive strength or running a cohesive simulation?

If the product is also subject to vibration condition, how to account for the dynamics effects?

 

[meltedEng]

Lee,

You would need to provide a much larger amount of information, unless someone comes along with specific knowledge. What material types, adhesive type, part type (flexible sheet metal or rigid CFRP?), industry, service.

Generally, you should do all of this empirically and expand or use test data from references in your industry.

Yes, you would take your stress analysis from FEM and start there, with application of the standard bonding calculation (area / shear analysis) similar to a weld. There are a few authoritative texts on these issues to go from first principles.

Depends on vibrations, but apply the strain and check fatigue. You should refer to industry specific guides since they will all consider different factors.

 

[Lee.Conti]

Used to do calculation for composite adhesive joint and taking forces from FEM in aerospace. Generally film and paste adhesive.

But it is in automotive and materials are plastic. Adhesive could be tape, film or double side tape but it is subject to vibration.

There is concern of dynamics factor but wonder how do you all consider this effect?

 

[Agent666]

It also depends on whether your adhesive is, stronger than the material being joined. For example is, the adhesive the thing failing or the underlying material.

I once designed a glued portal knee joint in Glulam timber, while it was glued, not a single check related to the actual adhesive being used as the failure was inherently through the underlying grain structure of the wood. As the adhesives used for Glulam production are by their very nature stronger than the wood themselves. The design was based on fracture mechanics, maybe searching for topics on fracture mechanics will lead you in a productive direction.