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About paula94

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  1. Hello, I work on a suspension construction. I have done done a static analysis due to vehicle mass (I managed to do both linear and lgdisp nonlinear). However, I also need to perform a dynamic analyis due to riding over an obstacle and I have encountered few problems with the simulations: 1) As an excitation I use a displacement of a triangular shape (picture below). It works fine for the direct transient (linear), however, when performing nonlinear direct transient (with and without LGDISP on) the excitation is not as I intend it to be (second picture). The plots show the displacement in the Y direction in nodes where the displacement is applied in the model. The actual input load data is a triangle as in the first picture. Therefore, I do not understand why when performing nonlinear transient the displacement starts to increase before it is larger than 0 in the input data. There should not be any loading applied before 0.100 s and when changing to nonlinear analysis somehow there is a loading. Also the system does not go back to the zero position. 2) the second problem is that when i use nonlinear direct transient the simulations calculates without any problem but when turning on the LGDISP option I encounter convergence problems: *** ERROR # 4966 *** Minimum time increment reached, analysis aborted. I tried changing the minimum time increment but it does not help. I use TSTEPNL and NLADAPT setup. What options should I change so that the convergence problems does not happen? Thank you very much in advance for any help.
  2. I have tried but I cant open the results file. How should I open it? Should it open in hyperview? Thank you for help in advance.
  3. Hello, I have a question concerning buckling analysis. If I use linear static load step and then linear buckling will optistruct calculate the buckling correctly if the buckling occurs according to Tetmajer-Jasinski and not according to Eulers? (the slenderness is higher than 40 but smaller than 100). I have performed the analysis and the results are wrong as if it was calculated according to Eulers. What should I do to obtain realisic results? I tried to add extra material parameters and do nonlinenar quasi static but its still not working. Thank you for your help in advance.
  4. Hello, I am wondering if there is a way to view results of forces on 3D elements? I have meshed my object initially with 1d beam elements and then I can see the force results using ELFORCE output, but it does not work with 3D elements. Is there any other way to view forces on 3D elements in results? Thank you in advance.
  5. Hello, I work on a vehicle suspension optimization. For that purpose I need to perform a dynamic buckling analysis of a tube (meshed by 1D beam elements). I have already performed static analysis, static buckling and modal analysis and the next step is performing dynamic buckling with force impulse. In order to perform this analysis I need to apply an imperfection of the geometry (initial deformation). The imperfection is supposed to be the first buckling mode from static buckling and the corresponding displacements are assumed as a coefficient 0.01, 0.05 etc. Therefore my question is whether it is possible to apply such buckling mode imperfection in OptiStruct, if so where I can find this option? Thank you for any help in advance.
  6. Hello, I am working on a static simulation of vehicles suspension in Optistruct. I am loading it with 2500 N. Is there any way to perform the same simulation in ex. 10 substeps. I need to obtain the results for 10 steps with load increment of 250N so that first step calculates for 250 N,the second for 500N until the finał step with load of 2500N. Is there any way to do it as in ANSYS (nsub)? Thank you for any help on advance,
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