I have modeled a cantilever beam in Abaqus to test metal plasticity option. The beam is cantilever, 10 m long, and discretized into 10 B21 elements with 1m x 1m cross section. The beam material is steel and is modeled using plastic option with final yield stress as 526.54 MPa (input file is attached).
I have selected NLGeom option for the single loading step.
When I apply load of 600000 kN which is greater than the load corresponding to final yield stress of 526.54 MPa, the solver is converging, but I find that the results are strange - the support reaction stays at 526540 kN corresponding to final yield stress. However, the applied load is at 600000 kN. Shouldn't the software stop the analysis - due to non convergence etc. rather than running to completion? The force equilibrium does not seem to be satisfied for static analysis. Am I missing something?
My concern is about detecting such anomalies in larger models - unlike this simple model. Are there any watch its for detecting such kind of situations.
I find that I get very different results when using different step sizes - I tried 3 initial step sizes - initial step size = 1.00 failed to converge very near to the expected yield load. Initial step size of 0.1 failed to converge at 2/3 of the expected yield load, and with the initial step size of 0.001, the analysis runs to completion.
I am attaching the inp file for this model.
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