optimiazation结果和analysis结果不同，为什么？

EmilZhao

请教个问题，相同的模型，相同的条件，optistruct优化得到的ITERATION 0中的柔度和频率值，和analysis得到的柔度和频率值不同，为什么呢？不应该是相同的吗？

715211229

有谁可以看一下10.0的这个MATINIT value是不是1.0？

EmilZhao

The results of iteration 0 in an attempted topology optimization are different from the results of a run with ANALYSIS.  What is wrong?

Nothing is wrong.  You have defined a design space for your topology optimization.  In an analysis-only run, the density of the design space is set to 1.0.  In the first iteration of the topology optimization, the density of the design space is less than 1.0, unless you have expressly set the MATINIT value, defined on the DOPTPRM bulk data entry, to 1.0.  Therefore, in the first iteration, the structure appears to be not as stiff as in an analysis-only run.
For topology optimization runs with mass (volume) as the objective, the default for MATINIT is 0.9.  For runs with constrained mass (volume), the default is reset to the constraint value.  If mass (volume) is not the objective function and is not constrained, the default is 0.6.
To perform an analysis only run with the modal parameters set to the values that will be used for the first optimization iteration, do not use the ANALYSIS command, and set MAXITER = 0.

dlxiaomingzh

计算的方式不同吧，ansys在线性方面比较强

EmilZhao

dlxiaomingzh 发表于 2014-11-11 20:37
计算的方式不同吧，ansys在线性方面比较强

是optistruct的analysis结果，不是ansys

changkonggu

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