returned -3 error flag

[Manya]

Hey!
When am trying to analyze my model its returning a -3 error flag as I increase the Analyze increment i.e,Analyze 10 is working fine but Analyse 100 is returning a convergence failure when am doing plain pattern Linear load application.But when am changing it to plain pattern Constant both analyze 10 and analyze 100 are working fine without any -3error. I am doing a gravity load analysis.I am quite unsure why this is happening.
Analysis:
constraints Plain
numberer Plain
system BandGeneral
test NormDispIncr 1.0e-8 1000 1
algorithm Newton
integrator LoadControl 0.1
analysis Static
I am working on opensees since a month.So I apologize if its a silly doubt.

[fmk]

if using Newton you should only need about 10 iteration steps.
if Linear problem you should converge in a max of 2 steps at every iteration; if more the model is not Linear.
if it was Linear you could use a Linear algorithm (no convergence check is needed)

analyze 100 does bring you to a total load factor of 10 based on your integrator command, analyze 10 to a load factor of 1.0
the constant only needs 1 analyze step, the load factor does not change at all . so analyze 1, 10, 100, 1000, 10000, 100000000000000000000 will all givethe sam result with constant

[Manya]

Thank you for your prompt reply.
I have one more question,how can I record the moment in a specific fiber of a section element?
like,recorder Element -file Element1.out -time -ele 1 section 1 fiber 0.10 0.10 stressStrain is given to find the stress strain at specific fiber of the section.But that option is not there to record the moment.
by using recorder Element -file ele1sec1Force.out –time -ele 1 section 1 force, moment can be found but not for a specific fiber.Can you please let me know how to record it as I have to check my strains that specific fiber based on the moment at that fiber.

Thankyou

[fmk]

there is no moment at a fiber .. the moment in the section is the resultant of all the forces * the fiber area * distance to neutral axis

[Manya]

Okay.So for recording the moment in a section do I have to do the moment-curvature analysis??
or is there anyway I can record the moment at the top of the section?