Bird Strike - Project - 2

Objectives,

         To perform the bird strike into the engine case. Assign the given material data with different parts. The usage of the new composite and hybrid metal reinforced composite structure in the engine component requires extensive testing. This project is to rotate the blades in the engine on the airplane and bird hit into the blade so as to find out the results and D3plot for all the parts of the system.
Procedure,

          When an airplane collides with a bird or debris during flight, the high velocities of contact can damage or disable engines, break windscreens, and threaten the structural integrity of an aircraft. While the majority of bird strikes will not affect an aircraft to be able to continue flying, the in-flight impact can pose a serious threat and have the potential to cause significant damage, or disabling the planes ability to fly.

           Aircraft certification standards for the Federal Aviation Authority (FAA) and European Union Aviation Safety Agency (EASA) require impact testing of the engine and the airframe externals. Testing the effect of impact demonstrates the resistance of the product to bird impact and can cope with damage inflicted by birds of different weights while in flight.

           

                      Fig. Meshed Bird Strike model setup with Engine casing, Blade, Bird

           Ls-Dyna is a general-purpose for transient dynamic finite element analysis it's capable of simulating the complex real-world problem. An explicit finite element program for analyzing the large deformation dynamic response of the elastic and solid structure models. The contact between the rigid bodies and deformable bodies which very useful in crash testing provided in Ls-Dyna. 

            In this project provided the whole assembly consist of a blade, casing, hub, and bird. Then, save it individual components either deleting the other component and saving it.

Material, Section and Part creation, 

             The parts of the bird-strike model setup were different material properties and section properties of the shell elements. Blades were connected to the hub the forming a rotating structure. the hub is a thick component when compared to the blade it isn't damage/failure. So the engine casing and hub are modeled with rigid material and the blade was modeled with Aluminium Elastic-plastic material properties given.

              

              The bird and casing material consider as the elastic where the material of the bird is similar to a human muscle and the casing material consists of the Steel. And the section of bird and casing is a shell and the element formulation is 2 and hub element formulation is 4.

               

Contacts,

          Contacts are mostly preferred for intersecting the components. Where the Automatic surface to surface contact for blades and bird, here this contact bird is a slave and blades is the master. After that, the Tied surface to surface contact for hub and blades where the blade is the slave and hub as the master. And foaming surface to surface contact to prevent the penetration between the blade and casing.

              

Boundary Condition,

            The casing is steady and SPC created its constraining all the direction. hub and blade rotate along the same axis and assign the rotational velocity. The bird is moving at x-axis translational it's defined by *INITIA_VELOCITY_GENERATION.

                  

Control card and database,

              Different type of control cards is used in that study control termination, control timestep. Control time step card is used for different timestep and explore the mass scaling approach and energy card is required to assure the hourglass and sliding interface energies are captured in the output.

             Database binary D3plot and ASCI options are written. database extend binary card is captured the strain value correctly.

Results,

             After completing all the files, simulation is run. The following data has been extracted from the results files.

                    

                                        Fig. Simulation of Bird Strike

Stress-Strain data,

              

                                                    Fig. Effective Stress

               

                                            Fig. Effective plastic strain

Mass scaling,

        The simulation of runtime case and complex scenario for reducing the simulation time, mass scaling is used. The TSSFAC is 0.9 for all the cases, the stress and strain data on the late is captured and check in the simulation. it shows the Strain and stress in the cases.

                  DT2MS   Mass     Added mass      Simulation     Stress on blades      strain on the blades

original          0         1.478           0                   920                 0.175                    0.2306

Mass scale    2e-4      1.478      0.098595            785                 0.229                    0.2306

              

                                                     Fig. Von-mises stress

             

                                                         Fig. Effective plastic strain

Conclusion,

          This project helps to understand the performance and procedure for how to set up the complex problem having the component in each different keyword file using the include keyword. Mass scaling, the stress and strain data on the late are captured and check in the simulation. it shows the Strain and stress in the cases and understands the effect of the simulation data.