What does AVSMOOTH do in the command "TINTP,,,,,,,,,AVSMOOTH"? Using AVSMOOTH causes ANSYS 11.0 to differ from a competitor's solution.
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The Newmark accelerations can be noisy for many problems. The Newmark assumption uses the average acceleration [(a(t) + a(t+dt))/2] in its calculation. Initial conditions and nonlinearities can cause the values at "t" and "t+dt" to oscillate (sometimes wildly). Rather than reporting these accelerations in the output, when AVSMOOTH is 1, we report the averaged value so that a smooth solution is seen. Not that there was a bug that resulted in no smoothing being done between 8.1 and 10.0, but that is corrected in 11.0. Your example shows why smoothing is good. The unsmoothed acceleration results oscillate between 2 and 0 times the applied acceleration, an error of a factor of 2, but the smoothed results are correct. This demonstrates why smoothing is the default. |
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