Incremental Dynamic Analysis

[obaidullah khan]

I have mailed you the SPF file with necessary explanation and evidence through my account obaidkhan6***@gmail.com. Waiting for your response.
Regards.

[z.gronti]

Dear obaidullah khan,

The problem is that the output file is too large. I ran the model as it is and the *.srf file is more than 38GB. I would suggest you to reduce the size of the output file by increasing the number of "Frequency of Output" in the Analysis Output tab, split the model to 2-3 models to cover all the required IDA scaling factors and you may also load the applied accelerogram with higher time step.

[obaidullah khan]

Dear z.gronti,

I understood the above recommendations and I really appreciate. I will apply them and will let you know here but I have only two confusions left.
1) I have check the manual regarding values of "Frequency of Output" but not get detail info there. Can you plz recommend/suggest any frequency value or any range up to which I can assign any value, so that my file size get reduce and I can obtain my desire results in the post processor without any divergence or subduction or any compromisation of results/values.
2) can I apply one accelerogram file in both X and Y direction in a single run (as I have applied in the accelerogram file that I have sent you in both x and y direction in applied load ==>nodal load in one go )or should I apply in only one direction in one time.

Regards.

[z.gronti]

Dear obaidullah khan,

In order for you to be able to define the frequency of output, you should take into account the initial number of increments/steps that have been defined in pre-processing and the number of steps that you want to receive in the output, i.e. in the Post-processor.
You may define the loads you want to and, by executing the other suggestions i made, reduce the size of the output files.

[obaidullah khan]

hello z.gronti

I did all the things that you suggest me in the above dialogue i.e. 1) I have use the accelerogram with higher time step (reduction of time steps from 8000 to 2000,1000,400 steps), 2) I have also alter the frequency value ( use 1,2,3 in different iterations), 3)I have break the file into 2 files according to the scaling from 0.25 to 1.25 and from 1.5 to 2.5. so my file size get reduced from 38GB to 2,3,4 7 GBs etc. and that's fine I am not receiving the error which I was previously been receiving in the post-processor. but now my analysis get stop in 3rd or 4th scaling for each and every time by giving the error elm_Inv, elm_Tol, adp-env, prd_ite. I have read the manual and watch video on seismosoft youtube channel regarding convergence problem and changes all the value in convergence criteria, element and global iterative strategy but still my analysis suddenly got stop in 3rd or 4th scaling by giving error ele_inv, ele_inv, ele_inv, ele_inv, this time only. What could be the reason, how it can be resolve.

Regards

[obaidullah khan]

I have tried each and every possibility given in manual and video but every time analysis stop at third scaling iteration and gives only errors elm_Inv and elm_Tol. kindly guide me in this regard. i have change there values in setting but still unable to run analysis completely. secondly these errors came suddenly to terminate the analysis, they not appear in any 1st and 2nd scaling iteration.

Regards

[seismosoft]

The divergence problems do not occur in the first two analyses because the IDA scaling factors and the loading is smaller.
The elm_inv and elm_tol messages mean that the program cannot find internal convergence in the diverging elements. This is usually due to large deformations in those elements. You can spot the problematic elements in the Convergence Details tabs of the Post-Processor. Check the deformations, probably the displacement demand is too large. you can also adapt the Element Convergence details in the program settings, although usually the effect of those settings is not decisive.
Note also that after a diverging solution in a specific scaling factors, IDA stops, since there is no point in increasing further the scaling factors.
Seismosoft Support

[obaidullah khan]

1) I spotted diverge elements in post proc converg, noted the displ breach value, changed value in the settings accordingly, ran analysis again but still 1 to 2 element shows ele_tol, ele_inv error in each iteration after 0.4 scaling and so on, but my analysis run that positive but not run completely e.g. if my end scaling is 2.2, the analysis stop suddenly at 1.6 scaling ite by giving ele_tol, ele_inv consecutively 3 to 4 time but when I check the tolerance limit in the post process convergence of the last 4 errors the displ limit did not get breach but analysis get stop e.g. the end errors are

Converg Message: ele_Inv
Displ Norm:0.00092055/0.01
Rotation Norm:0.007747/0.01 (this error 3 to 4 times)

what is meant by this whole scenario? Does my building members has limit up to that point that's why analysis get stopped or still there is something else to do to get ride of from this convergence issue?

2) Secondly in one of my accelerogram file my building went up to 1.40 scaling (with 1 to 2 ele_tol, ele_inv error in each iteration), the fluctuation of accel file was normal while in the another accelerogram file which contain high fluctuation my building went up to only 0.6 scaling. So is this the way in IDA to end the analysis suddenly where limit of building get breach or analysis should run smoothly up to the end scaling?

[seismosoft]

The IDA analyses stop if at one scaling factor divergence occurs.
This is because the size of each analysis in terms of bytes should be constant for the program to read correctly the results from the output file. However, note that once you get divergence at a LF=0.6, then you will almost certainly get divergence for a LF=0.8.

Seismosoft Support