Bird Strike - Project - 2

Aim

- To simulate a bird strike on a turbine.

- Understand the usage of include card for multiple parts (materials, BCs, Section) , so multiple personnels can work on a sngle project simulataneously.

Explanation and Procedure

Unit system used for this project kg mm ms KN GPa

Renumbering

A consistent numbering approach 100000+ for nodes, 500000+ for elements, and 1000+ for the parts which are hub, case, blade and bird.

Material cards

Bird, Hub and case are provided with elastic material as the focus in this instance is to find the perfomance of the blades during strike.

Blades are assigned with Mat piecewise linear plasticity with plastic region defined using the given curve (given). Material assigned is derivative of aluminium alloy.

Section Creation

Blade, bird and case are made of shell elements hence shell sections, with element formulations as shown in the figure below. hub is given solid section card.

Hub is given Element formulation with quadratic tetrahedron element with nodal rotations.

Boundary Conditions

Case is constrained in all DOF using the SPC card.

Hub and blade set is given a rotational velocity (1 rad/ms approx equals to 9549.29rpm) in x global axis.

Bird is given a 250mm/ms velocity in the global axis towards the blades.

Contacts

Blade is given self contact , hence the slave part with blades only needs to assigned in the card.

Automatic surface to surface contacts are created with bird as master segment ; blades and hub forms the slave segement for this contact.

Another Automatic surface to surface contacts is created with master as case and blades as the slaves.

Control termination is defined for 2ms and other database cards such extend binary is requested.

As the bird approches the blades , it can be seen that the some elements of the blades getting deleted once its gets failed due to high kinetic energy collision.

The global energy figure describes the drop small in the kinetic energy due to the impact and hourglass energy is well within the limits of 5% of the total energy to remain stable.

The Impacted blade element has maximum stress value of 0.252 GPa.

Debugging and Trials

- Engine case needs to constrained in all DOF , for replicating a real situation.

- Initial velocity needs to be applied carefully, there are some scenarios were in which bird and just bounce of the blades.

Conclusion

- In this project different boundary conditions are applied along with renumbering approach was used.

- Incidents like this are well-known in the aviation world. Each year, bird strikes cause an estimated 400 million dollars worth of damage to flying aircraft with the majority of incidents inflicting destruction to aircraft windscreens or engines. This project needs the application of SPH and other parameters to emulate the real physics.

- In terms of design manufacturing a turbine should be such that it sustains such strikes without harming other parts of the craft.

- Kindly run the dyn file to get the output files ( Due to limitation of upload limit, output files had to be removed)