FEA help with Orthotropic Parameter Values for Western Red Cedar 12%mc OR 'accounting for wood grain in FEA'

I have found a pdf that has pretty extensive listings of mechanical properties for wood and I am trying to fill in all the orthotropic parameters for a Western Red Cedar at 12%mc as a new material in my FEA project. Here is a link to that pdf: https://www.conradfp.com/pdf/ch4-Mechanical-Properties-of-Wood.pdf

Here is the page in the pdf that begins its orthotropic discussion:

Here is my parameter table in the project which I need help with: https://www.simscale.com/workbench/?pid=4486940413736144120&mi=spec%3Ab9c08495-0fa1-4c19-bb4e-d9ed4ce9bacc%2Cservice%3ASIMULATION%2Cstrategy%3A54&ps=analysis%2Fmaterials%2F0

Here is my attempt at filling in the blanks with my notes and questions added on the image:

With those numbers my results don’t pass my internal reasonable meter :frowning:

Can an FEA expert please come to my rescue?

Maybe @BenLewis, my FEA hero of the past…


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Hi @DaleKramer,

Thanks for this very pertinent question. I am from the FEA side, but I just worked with metallic materials throughout my career, so I am not the best guy to tell you how you can obtain these orthotropic values without an experiment (like a tensile test for wood I guess, not sure how it works for this material). But, let me tag @rszoeke here who likely have great insights on that.

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As is usually happens, the clarity provided by forcing myself to present my issue into an organized forum topic allowed me to probably solve this issue myself.

After re-reading the orthotropic discussion in the pdf, which I linked to in this topics 1st post, I was able to calculate all the orthotropic parameter values that SimScale wants.

My only assumption now is that Grt = Gtr , I hope that is a close approximation and which I hope someone out there can ‘talk to’ by a further response to this topic.

Here is my self-corrected parameter table:

And some results that pass my internal reasonable meter at first glance: :slight_smile:

Sorry for jumping the gun here.