Autodesk Robot Structural Analysis
Autodesk Robot Structural Analysis
(OP)
I would like to know how good Autodesk Robot Structural Analysis is compared to other renowned products like SAP2000, RISA-3D etc.
Thanks in advance!
Charles
Thanks in advance!
Charles





RE: Autodesk Robot Structural Analysis
RE: Autodesk Robot Structural Analysis
RE: Autodesk Robot Structural Analysis
RE: Autodesk Robot Structural Analysis
RE: Autodesk Robot Structural Analysis
The lack of support material is really frustrating,
But, anyway, Robot ME is a great engineering software despite some significant difficulties in setting up correct models.
I hope Autodesk won't spoil it. Since their having bought Robot from RoboBAT, they did absolutely nothing to improve the software.
The Robot's strongest point is the very convenient user interface. I would recommend it for all FEA tasks, and it is especially suitable for steel design.
RE: Autodesk Robot Structural Analysis
Thereby revealing a disturbing lack of experience by which to make such a recommendation.
How is it for crash simulation of cars?
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: Autodesk Robot Structural Analysis
RE: Autodesk Robot Structural Analysis
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: Autodesk Robot Structural Analysis
I think this to some extent is a question of not speaking the same language.
Robot is as far as I understand it an excellent software and compares well with other softwares in the same category. Software's like SAP, STAAD etc.
But it doesn't compare with softwares like ANSYS, ABAQUS, Nastran etc. And that opinion comes from the guys developing Robot.
I was at a demo and they called Robot a FEM-software. I asked afterwards how it compres to for example ANSYS. And the reply was "We are not in THAT division".
So I would say, "All FEA tasks"? No definitly not.
Structural FEA in terms of steel frames etc? Sure, as long is it doesn't get TO nonlinear or TO dynamic.
Regards
Thomas
RE: Autodesk Robot Structural Analysis
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: Autodesk Robot Structural Analysis
RE: Autodesk Robot Structural Analysis
- Linked with Revit Structure already (and works fine), see the Revit Extensions!
- Guys doing RSA are those that worked with RoboBAT before the acquisition: No major change there, I think.
- Robot is for STRUCTURAL FEA, also Non-Linear and Dynamics
- I have been doing and training linear, non-linear, dynamic, beam, plate and solid analysis with RSA over the past 7 years and also been using STAAD.Pro long before Bentley bought it.
I am happy with Robot - even with its problems in some cases.
RE: Autodesk Robot Structural Analysis
How do you manualy create an envelope load case in Robot. The load case creation system seems very powerfull, but complicated. It sounds like you get paid for this sort of help. So if you can help me, Thanks. Otherwise I would be willing to pay for some training or for some additional documentation if you have it. Where are you located?
RE: Autodesk Robot Structural Analysis
But during design of members, Robot use envelopes of combinations in automatic way.
During design of reinforced concrete members for example.
If you want to display results of some load cases like envelope you need to type numbers of load cases in that field by dividing them by space.
I use robot from earlier version, and i think that very nice software.
RE: Autodesk Robot Structural Analysis
RE: Autodesk Robot Structural Analysis
I'm speaking as an almost daily user of SAP2000, and I have a good friend who uses Robot and he loves it. My observation is that there is a huge unawareness among FE users as to capabilities of structural software, which seems to be described as "frame element" only. this is nonsense
1) SAP2000 can perform linear FEA analysis as well as nonlinear time history using direct integration or FNA analysis for models with frames, and/or shell/membrane and solid finite elements. I understand that both Robot and Midas offer nonlinear time history capabilities but I have no personal experience with those programs. Based on the comments in this thread, it seems there is widespread unawareness about the ability to run nonlinear structural FEA with Robot or SAP2000.
2) My consulting firm worked with a Canadian company, Hatch, about 3 years ago, a company which used ANSYS, SAP2000, and Staad for their structural and FE requirements. SAP2000 had replaced ANSYS for FE dynamic analysis of foundations supporting vibrating equipment modeled with FE and because SAP was more productive, and SAP2000 was in the process of replacing Ansys in the application of pushover analysis involving nonlinear material analysis of frame elements. A year later, I was involved in a consulting project in which SAP2000 was replacing Cosmos FE for nonlinear snap though buckling analysis involving large deformations. So the idea that only traditional FE programs like Ansys, Algor, etc should be used for FE or nonlinear analysis is an idea which is wrongheaded in many applications.
3) Face it, basic FE tasks like response spectrum earthquake analysis, load combinations, manipulation of local axis of FE elements, and rotation of local axis of frame elements can be a bitch in many/most FE products compared to many of the structural programs. And of cource, FE products offer little or no design codes.
It's unfortunate that the Robot presenter cited above in this thread made such a blanket statement when questioned about comparison to Ansys, because Robot, or SAP2000 may have been superior choices for many applications involving FEA, depending on the design application.
Having said that, for basic heat transfer analysis, thermal load across a wall, we could not use SAP2000 or Staad. Both programs offer thermal load, but that's it. Also, neither program offer kinematics, or temperature dependent material properties, so I undestand where traditional FE programs offer value. Structural programs offer zero in multiphysics. So please understand that I'm not sugar-coating, I'm just sayin
Bottom line - FE programs are being used in many applications where certain structural programs are far better suited and also more economical. Just open your eyes and your minds
RE: Autodesk Robot Structural Analysis
I don't mean to be rude but when you ask if FEA people are aware of what structural software can do. Obviously I can only speak for myself but I have to ask, are you aware of what general FEM-software can do?
The reason I wrote my post was the statement that somebody recommended Robot "for all FEA tasks". That's plain wrong. I think I could write a list of 5 - 10 analysis types or special applications. And no software in the world, "structural" or "general", could do them all. So I don't thing "all" should be used in that context at all.
Greg mentioned "crash analysis". I don't know of any "structural" software that can do that. And I have a pretty good idea what they can and can't do. I have collegues who use them daily (primarily STAAD but we have others as well). My work can on occasion be to run the analysis they failed to do in the "structural" software with a more "general" choice.
You say that some things can be a bitch in general software, very true. The time required to be efficient is also often less in structural software. On the other hand, the possibilities in a general pre/post processor exceeds the possibilities in the typical structural pre/post processor. And the general choice usually means that it can "talk" to several solvers. The structural choice often means one solver.
Once you have learned the general software it's very often faster to work in that alternative. And the control of the solver is usually much better. But again, it often takes longer to learn.
Obviously there are cases when the structural software is a better choice. It usually cheaper in addition to the other advantages (speed of learning etc).
As for the presenter of Robot, I would say that he knew what he was talking about. Robot isn't Ansys just as Abaqus isn't Ansys. That doesn't mean that Robot is bad. Just make sure that it fits your needs before you buy it. If you need Ansys, don't buy Robot.
Finally, you mentioned SAP200. I don't use it but was part of a test of it some years back. We didn't buy it because it didn't fit our needs at the time but it's not a bad choice.
The structural softwares have a huge undertaking in keeping the codes up-to-date. And for that reason I don't think they will ever catch up with the analysis capabilities in the general FEM-softwares. But if you need codes and don't need certain dynamic or nonlinear capabilities then general FEA might be a bad choice.
It entirely up to you.
Regards
Thomas
RE: Autodesk Robot Structural Analysis
This is something that is taken for granted in a general FEA code.
RE: Autodesk Robot Structural Analysis
~~~
Please re-read my post, since I never claimed otherwise. I specifically responded to your comment about the Robot presenter who said that Ansys, Abaqus, etc. were on a different level, suggesting a superior level. In many cases yes, other cases no. And btw, as you know, many general purpose FEA programs are similarly not well suited for crash simulations either. Another commenter mentioned nonlinear time history analysis, which indicated to me an unawareness that some structural software products can perform nonlinear TH analysis. I was specific in listing applications where certain structural programs may offer advantages over general purpose FEA programs, and I listed specific shortcomings. Along these lines, it would be nice to know of the specific reasons why your company did not purchase SAP2000 at the time. Were there multiphysics requirements? Heat transfer needs? If so, that's completely understandeable. In other applications, that may not be the case. I agree with your observation that structural programs are limited to one solver, although for many applications that is not a problem. Application programming interfaces are available with several structural analysis programs, facilitating their integration with other programs
I would ask Johnhors to explain what a "free-free" modal analysis involves, and further to name the structural software program he refers to as having limitations so that we can be talking apples-to-apples. In SAP2000 I can run a modal analysis based on an unstressed state, modal analysis based on multiple pre-stressed cases, and Ritz vector analysis all in the same run. I'm curious as to whether most FEA programs can do the same. Do FEA programs even offer Ritz vector analysis? Because we take it for granted
I stand by my statement that in many applications general purpose FEA programs are used in applications where certain structural software such as Robot or SAP2000 would be far better suited.
RE: Autodesk Robot Structural Analysis
RE: Autodesk Robot Structural Analysis
SAP2000 seems to have no problem with such models although as John points out there are other structural programs that can't do this.
RE: Autodesk Robot Structural Analysis
First of all, I hope we don't have to get into an argument over this. It's always nicer to stay friends.
I agree with you that in many cases the so called structural softwares are egual or better for certain applications. One reason can be that they often "hold your hand" to a larger extent then some more general softwares. BUT the general software often offer a much larger solvercontrol. Personally I prefer the general software. I like to control the software and not viceversa.
"Structural codes can do nonlinear", again true. But nonlinear is a huge subject. Everything from crash analysis to surface contact and advanced material models and beyond.
What I mean is that regardless of what you want to do with YOUR software you have to make sure that it can perform beform you buy it. To say that "it can do nonlinear" isn't enough because its a huge subject.
Just as dynamic analysis is a huge subject. I have seen a presenter say when asked say "Sure we can du a dynamic analysis". What was available was eigenfrequencies.
You ask why we didn't buy SAP200. The problem was linear statics. We had non-US trafic loads and very complex loadcombinations. We had a very specific request regarding the resultpresentation and it couldn't be done. Might be possible today but at the time it was impossible. We had a software tht could do it but wanted a more modern interface. SAP wasn't it.
I think that what Johnhors is refering to by free-free is a unconstrained model, like a spaceship or an aeroplane.
It's a very efficient way to troubleshoot certain problems in models. Especially when parts haven't been merged together properly. You run a eigenfrequency analysis and see it there are any free parts (with f = 0.0 Hz). Some solvers crash under those conditions others don't.
I won't go into detail about every can and can't in different softwares. The OP was refering to Robot and I think we are OT enough as it is. If Robot is a good choice or not is ultimately a question about what the application/s is and what codes you require. Codes is a big issue for structural FEA in my experience and not an issue at all for general FEA. That is at least one big difference.
Since Autodesk bought it my guess is that Robot will evolve, now they have better resources. Probably as the analysis engine together with Revit. We'll se what happens in the future.
Regards
Thomas
RE: Autodesk Robot Structural Analysis
Thomas
RE: Autodesk Robot Structural Analysis
~~~~
This is the 2nd or 3rd time that you've directly or indirectly attributed statements or opinions to me that I have never written, nor do I believe them. I NEVER suggested, nor do I believe that "nonlinear analysis" is some all-encompassing statement. There are obviously many types of NL analysis, which is why I've gone out of my way to be specific. Neither have I suggested that "capable of dynamic analysis" explains everything.
Thanks for your reply regarding your evaluation of SAP2000, although you didn't mention enough specifics to enable a reply. SAP can generate bridge influence lines, it can automatically export directly to Excel and it offers an API, so output result options have likely improved since you last evaluated. Or not, depending on the specifics. What program did you choose over SAP? SAP has gone through a lot of changes and enhancements, particularly over the past 4 years or so.
I've tried to be specific in my comments, pointing out actual real-life applications where I have seen structural analysis software turn out to be more productive than general purpose FEA in advanced analytical applications. Again, response spectrum dynamic analysis is far easier and more efficient in most structural programs as compared to general purpose FEA programs, most of which I've seen, force the user to fake out the program by defining some mass at the base. That's just one example. Pushover analysis involving nonlinear material plastic hinges is another application where some structural software programs are better suited than, say, Ansys or Algor, for common nonlinear material analysis design requirements. Analysis of concrete foundations modeled with finite elements supporting unbalanced dynamic loads is another application. At the time, Ansys could not even provide a section cut for solid finite elements in order to report integrated shears and moments. Load combinations is another advantage where structural software tends to offer significantly more than general purpose FEA.
How about an honest show of hands.. how many of you were completely unaware that there are structural analysis software capable of nonlinear time history analysis? Specifically, nonlinear TH for NL boundary conditions (gaps, friction, multilinear plastic springs), nonlinear TH for large displacement analysis and nonlinear TH with nonlinear material plastic hinges? In addition, there is NL staged construction and creep and shrinkage available through structural software programs. I'm admittedly being presumptuous, but I'd bet that a lot of you were unaware that programs like SAP2000, Robot, and GT Strudl can perform that sort of advanced analysis.
RE: Autodesk Robot Structural Analysis
So I would say, "All FEA tasks"? No definitly not.Structural FEA in terms of steel frames etc? Sure, as long is it doesn't get TO nonlinear or TO dynamic.
You should be honest enough to own up to your earlier mistatement of facts when challenged. Contrary to your assertion, several structural analysis programs offer more than analysis of "steel frames" as well as offeing nonlinear analysis and dynamic analysis, including dynamic analysis. Anyone can read what you wrote. You made a mistatement of fact, and when called on it, you refused to admit your error.
RE: Autodesk Robot Structural Analysis
First, in your previous post you said that I put more or less put words in your mouth. Sorry about that, it was never my intention. When I wrote "you" in that sentence I did not mean you personally. I meant "you" the analyst as in anyony doing the analysis, but that wasn't clear. Sorry about that.
Then you latest post. You say that I have made a mistatement of facts regarding structural FEA. In what respect?
Havent we agreed on that structural FEA can't do all FEA tasks? That's what I stated, nothing else.
And I wrote "steel frames etc", I was never specific regarding the "etc". That wasn't an accident
Finally, when I stated that it shouldn't get "TO nonlinear or TO dynamic". I was thinking about things like contact like multibody-contact of moving bodies. Or material models like hyperelastic. Or ......? Greg mentioned crash analysis.
Note: I don't think I have claimed that EVERY general software can do all of the above mentioned. But a general pre/post processor can usually "talk" to one of the solvers that can.
Sure, we can look specifics like you do and claim that structural FEA is just as good. It might be for some applications. You for example mentioned response spectrum analysis in your previous post. The "fake mass" that sometimes is used. There is nothing "fake" about the large mass method. I think it comes from the aerospace industri. And there are often other options in general FEA if you don't like "fake mass", unlike structural FEA.
If you think I've made an error and unfairly critizised structural FEA. I was just trying to point at some differences. Mayby I have faied miserably.
You have been very specific about the capacity of SAP2000. Since this tread is about Robot I have tried to keep it more general. I have colleges who have tested both of them and they have their pros and cons. At the time I thing Robot was considered better partially due to the connections with Revit. And it shold be possible to get the model from Robot to a general software but that might require some programming of the API.
I'm convinced that whatever software you intend to buy you need to test it and make sure that it fits yur needs. If you end up in the structural or the general "world" is not really important.
As for SAP2000, the reason we skipped it there were two problems if I remember correctly.
First, when we look at the results. For the design we needed max/min moments (envelops) and the associated axial forces and shear. We could only get max/min of everything. It worked if we used the internal design engine but since we had other code requirements it didn't work. We needed everything "on paper".
Second, bridge loads. We needed more general loadtrains then were available. Like for example, two or three concentrated loads (or loadgroups) moving independantly of each other. Now the code has changed so it might be enough with two loads (or loadgroups) independant of each other.
Regards
Thomas
RE: Autodesk Robot Structural Analysis
There are plenty of structural specific applications that advertise non-linear capabilities. I do very much agree that these structural programs (when appropriate) will be much easier to use than NASTRAN or other really high-powered FEA programs. But, that's at least partially because I'm a structural guy.
Even so, some of those program's actual capabilities do not compare well to what is suggested based on their advertising. Therefore, we should all be cautious about using programs without first confirming their suitability for our project.
RE: Autodesk Robot Structural Analysis
I completely agree with you. We all need to confirm that the programs we use are suitable for the projects we use them for. THAT was what I was trying to say. Thank you for your conclusion.
Regards
Thomas