SimWe仿真论坛 » A02：LS-DYNA » 请问ansys/ls-dyna中如何控制输出结果内容？

cwedone 发表于 2008-7-15 17:01

请问ansys/ls-dyna中如何控制输出结果内容？

隐式分析中可以通过outres来控制根据需要输出节点位移解，或应力解单元解等
BEJK3R-| dyna中没有找到相关的选项，好像默认是所有解都输出，结果文件大得无法接受，每次求解完都有十多g的结果文件Y,X+ZQsV3`$VN5B

@&Z6} PRJ 另外，显示动力分析中如何控制求解子步步长，隐式分析中通过载荷步，载荷子步来确定，显示分析中子步步长是如何确定的~/YG1CH*o*Q
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知道的同志告一声，非常感谢

lqx403 发表于 2008-7-15 22:05

我只知道控制d3plot文件的输出间隔，这个的确能减少很多空间

cwedone 发表于 2008-7-16 09:35

谢谢lqx403[x"Y}Z
增大文件输出间隔确实能减小输出文件%[z{fH o
不过我要在时间历程后处理器中画位移时间曲线，所以输出文件间隔不能太小8Gr(S0x,t$K6b
所以想控制结果的输出内容，隐式分析时我就是这么干的，可是显示分析中找不到这个选项

shouxinwj 发表于 2008-7-16 12:02

这是个问题，麻烦知道的吼一声啊，谢谢

yulyu 发表于 2008-7-16 14:51

*database_binary_extent选项看看．

cwedone 发表于 2008-7-16 15:27

回复 5# 的帖子

yulyu能否说清楚点，没找到这个选项、CG9VRdY$fUa"E8h
另外显示分析中，其子步步长默认是怎么计算出来的，我求解时模型的子步步长为0.78us，我通过time step control将其改为0.8us，会不会有什么大的影响

yulyu 发表于 2008-7-18 11:13

Sorry, 是*database_extent_binary.定义这个选项与不定义这个选项d3plot大小不一样的.
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*R)W/@U lvZ-rB 最小时间步,为了稳定收敛. 最小时间步基本上随着计算的进行而变小的.只要能计算就行.
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从关键字手册摘一点:
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1. During the solution we loop through the elements and determine a new time step size by(pVO+Lhx'X
taking the minimum value over all elements.JKxM*CJE
Δt n+1 = TSSFAC *min {Δt1,Δt2 ,..., ΔtN }
'?s/d|:b}Ud.KjZm where N is the number of elements. The time step size roughly corresponds to theh,e+M/~Z+u y
transient time of an acoustic wave through an element using the shortest characteristic
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f4j distance. For stability reasons the scale factor TSSFAC is typically set to a value of .906rY~%s:|Or,z-[3p
(default) or some smaller value. To decrease solution time we desire to use the largestC
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possible stable time step size. Values larger than .90 will often lead to instabilities.
?ZK7_ X;~:D Some comments follow:
L7\Jr0?@#\T • The sound speed in steel and aluminum is approximately 5mm per microsecond;
9I,a(O+u4RT$aM%H therefore, if a steel structure is modeled with element sizes of 5mm, the computed~ x8t8uD'AMO
time step size would be 1 microsecond. Elements made from materials with lower
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{ sound speeds, such as foams, will give larger time step sizes. Avoid excessivelyTF(z,\[!Z$Sz)v8w
small elements and be aware of the effect of rotational inertia on the time step size in
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}/h the Belytschko beam element. Sound speeds differ for each material, for example,8t/q:_eZ#u8Y'~0h2iu
consider:WRTn,FZ N{
AIR 331 m/s
~3A;Il$XH WATER 1478uK8J*YjL C\
STEEL 5240
S_ }2{[sl? TITANIUM 5220B[ Xh1|y[m
PLEXIGLAS 2598
}I8syIj • Model stiff components with rigid bodies, not by scaling Young’s modulus which can8hu.c-HT@1wc
substantially reduce the time step size.
4_"@S:o A7z • The altitude of the triangular element should be used to compute the time step size.MofX"~8H7e#p
Using the shortest side is okay only if the calculation is closely examined for possible
!qh$@9PQN instabilities. This is controlled by parameter ISDO.

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