[MBDyn-users] Problem about External Force Module

MBDyn users list mbdyn-users at mbdyn.org
Wed Sep 2 00:39:16 CEST 2020


Hi Runsen,

Thanks for your advice. I ran the file without the external force and MBDyn worked normally. But when I ran the file with the external force module with the command “mbdyn beam.mbd -P -P”, it shows the following error information:
…
Eq       274:                    0 AxialRotationJoint(11): orientation constraint gx
Eq       275:                    0 AxialRotationJoint(11): orientation constraint gy
Eq       276:                    0 AxialRotationJoint(11): angular velocity constraint wz
	Iteration(0) 103.805
		SolErr 0
UseSocket::~UseSocket: shutdown: socket=15 status=0 time=Tue Sep  1 15:18:20 2020

UseSocket::~UseSocket: close: socket=15 status=0 time=Tue Sep  1 15:18:20 2020

An error occurred during the execution of MBDyn; aborting... 


I don’t know what the hints mean…

I checked the codes and found that MBDyn ran the python API  function mbcNodal.nodal.send(False) normally (return 0) but stopped when it ran the recv() function at the first time step:

mbcNodal.nodal.recv()  #####receive new kenimatics from peer and external solver can touch it

This function returns -1.

Does “shutdown" mean the socket failed and the kinematics are not calculated and sent from the peer?

Jun

> On Sep 1, 2020, at 10:48 AM, MBDyn users list <mbdyn-users at mbdyn.org> wrote:
> 
> Dear Jun,
> 
> Hi,
> 
> I am also working on co-simulation between MBDyn and other softwares recently, so I am very interested in your questions.
> 
> I check the "beam.mbd" file, but I cannot find any problem.
> 
> From the file "log.mbdyn", it seems that the problem is from MBDyn side, and MBDyn stops at the first iteration of the derivative process without any hint. So, maybe you can run the file without the "external structure" first to see if MBDyn works normally, and also try to carry out the command "mbdyn beam.mbd -P -P" to get more hints from MBDyn.
> 
> Maybe others could give you some detailed suggestions.
> 
> Best regards,
> 
> Runsen.
> 
> 
> On 01/09/20 06:40, MBDyn users list wrote:
>> Dear all,
>> 
>> Sorry to disturb you. I also noticed that the solver sometimes ran well during the same case and the API showed that:
>> 
>> cmd to peer: 7 (NEGOTIATION)
>> cmd from peer: 8 (OK)
>> cmd from peer: 2 (REGULAR_DATA)
>> ...
>> (During one time step)
>> cmd to peer: 2 (REGULAR_DATA)
>> cmd from peer: 2 (REGULAR_DATA)
>> ...
>> 
>> cmd to peer: 6 (REGULAR_DATA_AND_GOTO_NEXT_STEP)
>> cmd from peer: 2 (REGULAR_DATA)
>> ...
>> (move to next time step)
>> 
>> I don't know why it gave two different results(REGULAR_DATA_AND_GOTO_NEXT_STEP and ABORT) in the same case. Does anyone know What will cause the solver abort instead of going to next step?
>> 
>> Best regards,
>> Jun
>> 
>> 
>> ----- 原始邮件 -----
>> 发件人: "mbdyn-users" <mbdyn-users at mbdyn.org>
>> 收件人: "mbdyn-users" <mbdyn-users at mbdyn.org>
>> 发送时间: 星期日, 2020年 8 月 30日 下午 9:52:17
>> 主题: [MBDyn-users] Problem about External Force Module
>> 
>> Dear all,
>> 
>> I met a problem when I used the external structural force module with python API.
>> 
>> (1)The solver stopped at the first time step t = 0.001s and the API showed the following information:
>> cmd to peer: 7 (NEGOTIATION)
>> cmd from peer: 8 (OK)
>> initialmbdyn5
>> cmd from peer: 2 (REGULAR_DATA)
>> cmd to peer: 2 (REGULAR_DATA)
>> cmd from peer: 5 (ABORT)
>> got ABORT from peer
>> Exiting StructureSolver
>> 
>> I think the right output should be REGULAR_DATA_AND_NEXT_STEP. Am I right?
>> 
>> 
>> (2)The log file showed that
>> ...
>> Eq       273:                    0 AxialRotationJoint(11): position constraint Pz
>> Eq       274:                    0 AxialRotationJoint(11): orientation constraint gx
>> Eq       275:                    0 AxialRotationJoint(11): orientation constraint gy
>> Eq       276:                    0 AxialRotationJoint(11): angular velocity constraint wz
>> 	Iteration(0) 103.805
>> 		SolErr 0
>> An error occurred during the execution of MBDyn; aborting...
>> 
>> There was no hints about this error and I don't know where the error came from. Is it related with convergency settings? Can anybody help me? Attached is the cantilever model and complete log files. Thanks for your attention!
>> 
>> Best regards,
>> 
>> Jun
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