SiteMap Page 126


Previous 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 Next

Class 3 Error

SYMPTOM:
When calculating a laminar flow, if one creates partial trn files including the wall shear stress, then this stress will have the wrong sign. Thus forces in CFX-Post will be
calculated as pressure force minus shear force instead of pressure force plus shear force. This does not affect res files or full trn files, when a different algorithm is used
to calculate the stress and force.

PROBLEM:
This is due to a bug in the CFX Solver in calculating the shear stress


WORKAROUND:<br>The workaround is to use a full trn file if sufficient disk space is available.<br><br>FIXED IN:<br>Release 11.0. Custom executable for Release 10.0 available on...

Changing the color cadet blue in .Xdefaults creates a malfunction in tcl-menus containing tabs, e.g.
Solution --> Analysis Type --> Solution Controls
Why does changing colors in .Xdefaults cause tcl-menu malfunction?


Development is aware of this issue with colors that have spaces between the name(e.g. cadet blue).<br>Unfortunately we cannot correct this - the problem is in the Tcl library.<br>There...

On Windows XP, after installing service pack 2 for windows the AUOTYN Help will not open.


Service Pack 2 for Windows XP installs some new security components that are related to Explorer and how other programs installed on you PC may interact with explorer. This new security setting is...

I used ALE parts to simulate underground explosions, I used ""Free(Lagrange)"" motion constraint for rocks and soils, and ""Equipotential"" motions for explosions. On the first cycle, I got an error message about ""negative density in state"" and then AUTODYN stopped."


When ""equipotential"" motion constraints are used to model high pressure and high velocity regions like explosives, AUTODYN automatically rezones the equipotential...

How to deal with ""Problem terminated -- energy error too large""?"


AUTODYN automatically calculates the energy balance and gives an error message when the energy error is greater than the tolerance (default is 5%). First, make sure the grid for all parts is...

How to deal with ""Problem terminated...Euler cell over emptied""?"


This error message shows that there is a large amount (>0.9) of volume fraction being transported into or out of an Euler cell in a single time step. Autodyn prints this message in order to...

How to deal with ""Program terminated -time step too small"" error message? "


""Time step too small"" is shown when the current time step is less than 10% of the initial time step. You can always decrease the minimum time step to continue the...

When I try to Execute my model, it shows ""wrapup cycle or time already exceeded"" even at cycle zero."


At cycle zero, this message reminds you that the wrapup cycle or time in your problem has not been specified. You should specify the cycle limit or time limit of your calculation in the Wrapup...

Why does AUTODYN sometimes look like it is not running and the screen stops refreshing?


Actually AUTODYN didn't stop running. When nothing refreshes in the AUTODYN View panel, it means AUTODYN is transferring data between your computer memory and hard disk, or saving a history...

I am running a very large problem and have many variables saved at every cycle in the history file. After it runs far beyond a certain cycle (e.g., 10,000 cycles), it looks like AUTODYN stops. Why?


Although it looks like AUTODYN has stopped it hasn't really stopped. In this case, AUTODYN is saving the history file because you have a very big history file there. The way to remedy this...

The clock is set back automatically and then AUTODYN cannot run. How can I fix this?


We never encourage AUTODYN users to set the computer clock back, even for a few minutes. This will kill the authorization file and thus AUTODYN will not able to run. When this happens, you can go...

When modeling a plate impacted by a projectile, I used the Euler processor for the plate part. Why is there no deformation being observed on the backsurface of the plate?


Generally the Lagrange processor is used in AUTODYN to model solids and the Euler processors to model fluids. If the problem includes fluid-solid interaction, either use the ALE processor for the...

In explosion problems, I have found that air flows into a part even when the explosive wave hasn't arrived there.


That's because you specified an incorrect value of reference energy for air. Incorrect specific energy will cause incorrect air pressure, which will be greater than or smaller than the...

How to deal with ""Problem terminated -- degenerate cells""?"


Firstly, make sure the grid for all parts is correct before running AUTODYN. Then, carefully examine the material properties used in the AUTODYN calculation. Next, if the grid and material...

Bulk failure is shown in Material/Status plot for an Euler part even though I didn't specify any failure model. Why?


The failure region you observed in the material status plot is actually void material. In an Euler part, when a material moves out of a cell, this cell is filled with void if no material or only a...

When running AUTODYN, Euler cells far from the flow field rapidly turn to negative pressure from zero or positive initial pressure within the first few cycles, even before there is any chance for acoustic propagation. How do I fix this?


The pressure drop you see is most likely because that region has a different initial density (lower) than the reference density. When the equation of state is evaluated in the first cycle it...

I ran an explosive detonation problem. What does it mean if ALPHA in the explosive region reaches 1.0?


ALPHA is used to indicate the state of explosives. At cycle zero, AUTODYN calculates the burn time of each cell filled with explosive material. The burn time is stored in ALPHA with a negative...

I encountered a problem remapping the results of a 1D wedge simulation of HE detonation onto a 2D Euler-FCT axial-symmetry part. There were no errors during the remapping process. However upon executing the problem, AUTODYN 2D terminates abruptly with the following error message: ""Negative density or pressure in SETFCT"". Why? "


Euler-FCT is a single material processor and only a material with an ideal-gas EOS can be mapped into an Euler-FCT part. If the explosive in the 1D calculation has enough expansion and an...

I compared the impulse time history calculated by AUTODYN with a conventional analytical model. I found that the analytical result is larger than AUTODYN's. Why?


It is expected that the pressure impulse calculated by AUTODYN is less than that calculated analytically by 20~30%. The main reason that some analytical models over predict the impulse is that...

In the remap tutorial, why is the equation of state of TNT switched from JWL to ideal gas? Where does the new reference density (10^-4) come from?


In order to improve numerical accuracy when the compression is very close to -1, we suggest changing the HE EOS from JWL to ideal gas and setting reference density to 1E-4. Actually, you can put...

In Lagrange/ALE calculations, gauge points are disappearing during execution. Why?


If the element where the gauge point sits is eroded away, you might find that this gauge point is undefined and all the variables at this gauge point are zero. So, make sure the gauge point...

How to deal with ""Error reading history file"" message."


AUTODYN will not read/write the history file if you do not have any gauge points in the model. Please make sure you have not deleted a cell where a gauge point is located. Also, make sure you have...

Why did I get the error message, ""Error #4 calculating principal values"" on the first cycle when I ran a 3D model?"


The principal stresses and the principal directions are calculated from the eigenvalues of the stress tensor. When the solution has not been found, this message is shown to notify the user. You...

I am running a shaped charge calculation using the Euler solver. The target is quite thick, 5 to 10 times the length of the fully stretched jet. To get the resolution that I need, I have to make the mesh very fine. The calculation is running on a high performance PC for almost two weeks. Is there any way to speed up the calculation without reducing the accuracy?


Estimate the length of the fully extended jet (L). Divide the mesh along the axis of symmetry into parts (subgrids) each length 1.5*L, then join all parts. Inactivate all parts except one in front...

I have made all the changes suggested by your FAQ's but still get "Problem terminated...Euler cell over emptied"


Try reducing the time step safety factor (Controls/Timestep Options)