FEA for a chair?
FEA for a chair?
(OP)
I'm designing a pretty basic metal frame armchair for small production. I need to make sure the alloy used and design pose no risk of breaking under a human load... I am debating whether to use aluminum or stainless steel and which types. Also, depending on cost and feasibility, I don't yet know if the frame will be forged or diecasted.
This may sound a bit much, but should I get a FEA report for this and how much can that cost me?... I just don't want to be sued by an angry 300 lbs football player who would have broken the chair (and hurt himself) after having sat on the chair 12 hours in a row in front of the tv, watching game reruns (and jumping up and down, and shaking the chair, and...whatever!) Thanks for your feedback.
This may sound a bit much, but should I get a FEA report for this and how much can that cost me?... I just don't want to be sued by an angry 300 lbs football player who would have broken the chair (and hurt himself) after having sat on the chair 12 hours in a row in front of the tv, watching game reruns (and jumping up and down, and shaking the chair, and...whatever!) Thanks for your feedback.





RE: FEA for a chair?
"The attempt and not the deed confounds us."
RE: FEA for a chair?
Do not think FEA first. Basic calculations should be carried out first. You may not need to go any further.
I suspect the chair design will be dictated by stiffness charecteristics rather than strength as such.
Keep the calculations with the design log. Should the worst come to the worst you will have to show that you have taken all reasonable steps to make a safe design.
TERRY
RE: FEA for a chair?
In real life, though, for everyday items such as chairs, you would grossly overdesign it to account for uncertainties in how the chair will be used. This might involve designing the chair for the weight of a 99th percentile human, and multiplying the weight by a large factor of safety (like 2 or 3).
In litigation, analysis results (or FEA) will not usually amount to a hill of beans, as a jury does not typically have enough technical background to understand how these results are obtained. In cases like these, there is no substitute for a test. You should therefore test your chair under all potential (normal) operating scenarios just to cover yourself.
pj
RE: FEA for a chair?
One last note: I've seen litagation filed against a porch swing manufacturer, not because it broke, but because it flipped over.
RE: FEA for a chair?