Bird Strike - Project - 2
Aim:
To perform and simulate the non linear transient dynamics problem of Bird Strike in Aero Engine by using explicit solver analysis in ls-dyna.
Objective:
The blades should rotate at a constant velocity but the casing should remain stationary. The cylindrical bird model should travel along its own axis and hit the blades. Use elastic material for the bird(2000MPa) and the casing(200GPa). The material model for the blades is attached. The velocity of the engine blades and the birds can be chosen so that blade failure can be seen within a short span of time.
The bird, casing, and the blades should be in different input files and there should be one main file referencing all the input files. The main file should contain only references. Control cards and boundary conditions should be there in another separate file. The reference include path should be such that the folder can be copied anywhere and it is able to correctly reference all the file and run the simulation.
Explanation:
the given keyword file BIRD_STRIKE is imported in the ls-prepost the file includes blades,Engine casing, bird and hub.
seperate the all parts and saved in .k file
SECTION PROPERTIES:
created the section shell card and given Elform16 for bird and assigned 15mm thickness.
created the section shell card and given Elform16 for blades and assigned 2mm thickness.
created the section shell card and given Elform16 for casing and assigned 1mm thickness.
created the section solid card and given Elform10 for hub
MATERIAL PROPERTIES:
For bird MAT_ELASTIC is used and the properties are RO=2.000e-6,E=2 and PR=0.47
For bird MAT_PIECEWISE_LINEAR_PLASTICITY is and used the properties are RO=2.715E-6,E=68.94,PR=0.33,SIGY=0.013 and FAIL=0.27 and load curve is also assigned.
For Casing MAT_ELASTIC is used and the properties are RO=7.8e-6E=210and PR=0.33
For hub MAT_PIECEWISE_LINEAR_PLASTICITY is used and the properties are RO=8.2e-6,E=145,PR=0.3,SIGY=0.81 and FAIL=1.e21
PART_UPADATE:
Parts are updated for respective section and material properties for all the parts.
BOUNDARY SPC SET:
Boundary_spc_set card is given to the casing for constraining in all the directions.
CONTACTS:
Automatic surface to surafe:
contact between Bird and blades i have given the Automatic surface to surface contact i f i not give the contact between bird and blades the bird can
penetrates into the blades. for this cotact slave as bird blade as master.
Tied Surface to surface:
This contact is permanent contact between hub and blades for this contact i have given slave as a blades and master as a hub if we not give this contact then blades and hub
are not connected and blades are move away from the hub.
Automatic single surface:
This contact is self contact this has only slave segment slave as a blades. if i not give this contact blades can penetrate into the another blade.
VELOCITY GENERATION:
*INITIAL_VELOCITY_GENERATION card is used for bird in Xdirection Vx=30mm/sec.
and the same card is used for blades for rotating we use OMEGA=0.25 and NX=1 here omega is angular velocity and it will take center point and rotates the blades.
the bird hits the rotating blades with the given velocities.
CONTROL CARDS:
the end time is given in *Control_termination the ENDTIME is 5ms
and also given the Time step scaling factor and mass scaling in *Control_time_step The values are TSSFAC=0.9,DT2MS=-0.001.
DATABASE CARDS
Database base cards are given for getting output D3plot and for knowing the global,material and sliding energies etc.,The DT values is 0.1
Results:
Vonmises stress are max effective stresses are 9.31e-2,min effective stresses are 0.0e0
the maximum Effective plastic strain is 0.27% and minmum strain is 0%.
kinetic,internal,total energies are ploted below.
sliding energies are ploted below because of the contacts sliding energies are came.
