Bird Strike - Project - 2
AIM:
To perform and simulate the non-linear case of bird strike in Aero-engine using Explicit analysis in LS-DYNA.
THEORY:
Bird strike pose a significant threat to aircraft structures, as contact with a bird while in flight can cause significant structural damage.
For more than 30 years, computational approaches have been used to design bird proof structures and they have proven to be a cost- effective alternative to costly physical certification testing with live birds.
The bird behaves as a soft body and flows over the target structure in a fluid like way at the velocities of interest, with the high deformations of the spreading material being a substantial problem for finite element simulation.
PROCEDURE:
case setup: The given keyword file BIRD_STRIKE consist of node elements for all the four parts collectively, ie, Engine case, Blade, Bird, and Hub.
STEP 1: OPEN THE GIVEN .k FILE
STEP 2: DEFINE SECTION, MATERIAL AND PART FOR EACH COMPONENT
1. FOR ENGINE CASE.
SECTION
MATERIAL
Then add SEC ID and MAT ID to PART.
2. FOR BLADE
SECTION
MATERIAL
Here I did not use Include option, Instead of this I have taken values from given .k file. Then I created a new material card. The material curve too.
Then add SEC ID and MAT ID to PART.
3. FOR HUB
SECTION
MATERIAL
Then add SEC ID and MAT ID to PART.
4. FOR BIRD
SECTION
MATERIAL
Then add SEC ID and MAT ID to PART.
STEP 3: CREATE NODE_SET
1. FOR ENGINE CASE
2. FOR BLADE AND HUB
3. FOR BIRD
STEP 4: DEFINE CONTACT CARDS
1. BLADE-HUB
2. BIRD-BLADE
3. ENGINE CASE-BLADE
4. BLADE-BLADE
STEP 5: DEFINE VELOCITY
1. FOR BIRD
2. FOR BLADE AND HUB
Considering 5000 rpm and convert it into Radiant from which Angular velocity OMEGA=0.5 rad/ms.
STEP 6: DEFINE SPC CARD FOR ENGINE CASE
STEP 7: DEFINE TERMINATION TIME
ENDTIM=3ms
STEP 8: DEFINE TIMESTEP
STEP 9: DEFINE OUTPUT
1. FOR BINARY, BINARY_D3PLOT, DT=0.1 ms
2. FOR ASCII, GLSTAT,MATSUM,NODOUT
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WHEN I RUN THE FILE FIRST TIME I GOT ERROR TERMINATION.
RESULT AND PLOTS:
EFFECTIVE STRESS:
EFFECTIVE STRAIN (v-m) ELASTIC
PLOTS:
In this Explicit analysis, When the bird hits on blade at a velocity of 70 mm/ms Internal energy increases and kinetic energy decreases due to the impact on blades. Hence we can notice that the plot satisfies the law of conservation of energy.
---------------------------Thank You----------------------------------------------