FEA safety factors?
FEA safety factors?
(OP)
Hi, I work for a company that makes heavy duty mechanical machines.
I am wondering what safety factors you guys use to comply with local standards?
I am in Australia and haven't noticed any standards that mention FEA.
Some help would be great!
Thanks!
I am wondering what safety factors you guys use to comply with local standards?
I am in Australia and haven't noticed any standards that mention FEA.
Some help would be great!
Thanks!





RE: FEA safety factors?
- Ask yourself why should there be any?
FEA is just a tool, nothing more nothing less (it is not an "expert system" as some vendors might lead you to believe !). As with any tool the quality of work is only as good as the craftsman using it. (Remember the old saying a bad workman blames his tools). For FEA for as long as I can remember there has always been the saying "garbage in equals garbage out", which is as true today as ever (and probably even more so).
Any standards or codes of practice apply, and are specific to the industry you are working in, and may or may not include FEA in their procedures.
Seeing your other post, I would strongly recommend that you attend a course on FEA and purchase some reading material. Avoid vendors training courses since all they teach you is how to use their software and a lot of the time induce attendees into using bad practices. For a start check out NAFEMS as their courses are vendor neutral.
www.Roshaz.com
RE: FEA safety factors?
beyond a reasonable doubt ? ... what's reasonable ??
test data ? similar experience ??
what are the consequences of a structural failure ? dead people ?? $m of costs ??
RE: FEA safety factors?
corus
RE: FEA safety factors?
ME, Cranes! Times are definitely tough
RE: FEA safety factors?
Some codes/standards place requirements on how FEA is to be done to capture the behavior of the structure, but again the FOS is a separate subject.
TOP
CSWP, BSSE
www.engtran.com www.niswug.org
"Node news is good news."
RE: FEA safety factors?
RE: FEA safety factors?
You need to decide on your level of ignorance in the following areas
-wrong loads
-wrong material properties
-wrong lifecycle expectations
-wrong analysis
-wrong customer usage profile
-wrong load
-wrong assembly methods
-environmental effects
-system interactions
You may observe a fair bit of redundancy in that list. There may be a good reason for that. And I may have forgotten something. There is no good reason for that.
Cheers
Greg Locock
SIG:Please see FAQ731-376: Eng-Tips.com Forum Policies for tips on how to make the best use of Eng-Tips.
RE: FEA safety factors?
RE: FEA safety factors?
Typically in analyzing structures the service loads would be factored up and the member capacities are factored down. Then the two are compared against each other. It makes no difference how you do the analysis. The aggregate "factor of safety" is built into the two means of factoring and is hard to quantify with a single number.
Standard building and material codes will have your load factors (ASCE7, IBC etc). Material codes will have the capacity reduction factors (AISC, ACI, etc).
RE: FEA safety factors?
These are not safety factors though. The safety factor is in the allowable stress for the material, which for vessels is taken from AS 1210 or supplement 1 depending on your method used. This is generally UTS/3.5 or Yield/1.5 but for structural work you should refer to the relevant code which will probably allow around 90% of yield.
You should read the codes and check first.