Bird Impact analysis

Altair Forum User

Hello everyone,

 

I am 1 yr exp. fellow in hypermesh .  now i have got the project on bird impact analysis of a aircraft which will be commencing next month .

I am preparing myself for that .The point is i have done some practice on aircraft wing which 'll be on  composite materials.when i do the comp. modelling in bulk data format it's coming but i dunno hw to do on block110 format /emoticons/default_unsure.png' alt=':unsure:'> . i followed certain things that are given in help menu but i couldn't make it . /emoticons/default_sad.png' alt=':(' srcset='/emoticons/sad@2x.png 2x' width='20' height='20'>

 

 

It would be good if i get a brief  steps on how to carry out comp. modelling with block110 format which 'll help me a lot! 

 

thanks and regards,

chandru

 

Altair Forum User

Hello Chandru.

I am using Block120 but they should not be that different. I imagine that you want to use shells.

You need to create a material law 25 and a property type 10 or

a material law 25 and property types 19 for each ply + p17 for the laminate

If the material for the interface between two plies is not simulated, the thickness and material

of each ply is the same, the two approaches are identical.

For simplicity, lets use approach 1 (M25, P10).

In the property card, under the variable 'N' you define  the number of plies (or sublaminates) which

at the same time is the number of integration points through the thickness. Depending on the selection

of 'N' an equal number of 'Phi' entries will appear. That is the orientation of the ply with respect to the

LOCAL system. The LOCAL system is defined with the 'Vx, Vy, Vz' entries in the same card.

 

For example: (Vx,Vy,Vz) = (0,1,0) it means that direction 1 of orthotropy is parallel to the global 'Y'

axis. Phi1=45 means that ply number 1 has an orientation of 45 degrees with respect to the local system,

so for the example given above, the orientation with respect to the global system would be 135.

 

I think you get it..

 

Finally in the Material card you enter all the material parameters in the LOCAL system again. Finally,

you assign both to the component and you are done.

 

There are also other ways but that's an easy way to start.

Hope this helps.

Let me know if you got more questions

Altair Forum User

hello Kounis,

 

thank you for the swift reply. /emoticons/default_smile.png' alt=':)' srcset='/emoticons/smile@2x.png 2x' width='20' height='20'> .

Now i certainly got the bird eye view of block110 format /emoticons/default_biggrin.png' alt=':D' srcset='/emoticons/biggrin@2x.png 2x' width='20' height='20'>

 

I tried with prop10 as you told and i got it but when i click composite layer icon , plies  are not getting displayed. /emoticons/default_sad.png' alt=':(' srcset='/emoticons/sad@2x.png 2x' width='20' height='20'>

 

And also when i was doing with prop;17/19,

For eg.  i need 4 plies (0,-45,45,90) for the ribs and spars having variable thickness whose sum is not equal to shell thickness. first i created 8 ply props(prop17).,2 stack props(prop19) and  MAT25, if i'm not wrong.

And i am certainly not getting   '(incremental angle)' i.e (for eg) what 'll be the  ,  for -45 ply orientation?.

 

thanks and regards,

chandru

 

 

Altair Forum User

The plies do not get displayed and i think that they should fix that, it is not your fault.

To define the thickness, you just add the value you want on the ply card (P19). The total thickness is defined in the laminate (P17).

Be a bit careful with the positioning of the plies!

To define the orientation, you need to define two angles.

'

 

The angle for layer i: = i +

where i is defined in the /PROP/STACK for layer i.

'

The first angle, Phi_i, is defined in the laminate (P19) and the second, DeltaPhi, in the ply (P17). For a 45 degree ply you can either

go Phi_i=0 and Delta_Phi=45 or the opposite: Phi_i=45 and Delta_Phi=0. Basically you can choose anything that sums to 45 but the rest do not make that much sense.

Also, the value Phi_i is common for all plies in the laminate.

 

I do not get the '...variable thickness whose sum is not equal to shell thickness.'. The variable thickness part is understandable but why is their sum not equal to the shell thickness?

After all, you define the shell thickness.

Altair Forum User

Hi,

 

Thank you for the reply. /emoticons/default_smile.png' alt=':)' srcset='/emoticons/smile@2x.png 2x' width='20' height='20'> .

I got confused with the below flag, but i got it clear now.

 

Ipos

Layer positioning flag for reference vector

Default = 0  (Integer)

= 0: layer positions are automatically calculated with regard to layer thicknesses. The coherence of global thickness with the sum of layer thicknesses is automatically checked.

= 1: all layer positions in the element thickness are user defined. Multiple layers may have the same special position. Global thickness is not checked in this case, since it needs to not be equal to sum of layer thicknesses.

 

 

thanks and regards,

chandru