ROPS, rollover protection 1

[mrMikee]

I have been asked to look at a ROPS design for a concrete delivery machine. Does anyone know if (in the US) this can be done on a structural program like Multiframe or RISA, or does it require a nonlinear FEA analysis of some kind?

I think the relevant spec is SAE J1040. Maybe CSA B352-M1980. Are there others?

Thanks,
-Mike

 

[GregLocock]

I think you need to identify which spec you are working to. For SUV roof crush, for example, we'd have to use a non-linear code, because performance is defined in terms of intrusion.

Your other option is to design a structure that can be analysed by hand, which, combined with linear FEA for the rest of the structure, should allow you to predict its performance reasonably well. That's a higher risk approach, obviously.



Cheers

Greg Locock

Please see FAQ731-376 for tips on how to make the best use of Eng-Tips.

 

[JStephen]

Seems like I've read that bulldozer roll cages are designed to absorb a specified amount of energy, rather than being just a stress-type analysis. But should be covered in Code of Federal Regs, I would think, if you can ever find it.

 

[mrMikee]

Thanks Greg and JStephen:

I am trying to get more info from the customer, also rummaging around the internet to see what I can find. I currently have Multiframe and CADRE so I'm not sure I have what it takes to do this. Things have probably changed a lot from when I did one of these in the late 80s.

Thanks again,
-Mike

 

[ccw]

Hi mrMikee,

FOPS and ROPS requirements are typically combined in the resultant cage design, depending on the industry. For instance, for forestry mobile equipment, OSHA 1910.266, the FOPS requires a solid top and mesh sides. A substantial FOPS can influence the structural design for ROPS and vice-versa. Ref. SAE J1040, J231, J397.

From Greg's comments, it is interesting to note that use of non-linear codes have progressed into regulatory/safety evaluation requirements for automotive design.

 

[gwolf]

Regarding JStephen's comments, I too have seen cages designed like this based on energy absorbtion via plastic deformation of the cage.

 

[ruble3]

I think CSA Standard B352.0-95(R2004) covers the design and performance requirements for agricultural and construction equipment for ROPS

 

[mrMikee]

I appreciate the comments.

I was hoping to have more info by now but haven't made any progress. Just wanted to say thanks for the help.

Regards,
-Mike