Weldment stress analysis

[Anonymous]

Hi everybody,

Hopefuly somebody have an answer to my question. I am running Autodesk Invertor 2013 Proffesional and I am trying to simulate stress analysis. Since I am familiar with technology and material issues I have a questionrelated to it. Does the simulation calculated also with the heat affection of material?

The trouble is that in welding process you are bringing a lot of heat into the material and if you will run the real material analysis of the weldment after the welding process you can find that the material has different mechanical properties, esspecialy the aluminium if it is originally hardened. So again the question:

Is heat affection involved in the calculation of stress analysis?

Thanx in advance.

Joe

[Inv_kaos]

Most aluminium design codes have different allowables for welded and non-welded aluminium structures. In this case you would need to create two different material types depending on your area of interest. However I don't believe the modulus of elasticity or the poissons ratio is affected so you could just use the same material for both, and then compare your results to the appropriate allowable strength from the design code (dependent on the reduced yield or UTS). You can also look into post weld heat treatment of the heat affected zone (HAZ) to restore close, if not the same, properties of the original unwelded Al.

[Anonymous]

To be honest I am not sure whether the welding process influence is involved to the calculations, since they would have to create few more databases for each welding proces and each material. Different welding processes have different heat input and therefore it is very difficult to describe to possible behaviour od material. It is not just the case of aluminium but also every other material provided in the database. I just wanted to know if somebody have an experience with theese calculations.

I was working more with the Solidworks, but since Autodesk provides the free licence for student and educators, I should have to look at it deeper to show benefits to the students. I am lecturing welding technologies at the university, so I was curious what is this software capable of doing with welded constructions, how precise would be the result and if its worth it to include some simulations into the excercises.

Joe

[Inv_kaos · Accepted solution]

I think I have already answered your question, what is it you are unsure of? For steel structures heat affect zones are prone to cracking so stress relieving is usually required for operation at low temperature and thicknesses over 1.5" give or take but the strength is not really affected. With aluminium the strength is greatly affected hence the reason the Aluminium design codes specifically give allowable strengths for welded and non-welded plate and sections. This is what you should follow to check the affect of the strength based on the grade and welding process.

As for the linear analysis, as I said earlier, the modulus of elasticity and the poissons ratio are not really affected (except when loaded at temperature). Therefore you should be able to use the same material. It is only if you use the safety factor plot that you will need different materials because it uses either the yield strength or UTS to calculate the safety factor.

I am not a material engineer and i am sure there are specific permanent modifications to the modulus of elasticity and poissons ratio that may be important at some research levels but for general stress analysis I believe it wont affect your results. Hopefully a material expert can comment.