# Homework Help: Nonlinear dynamic modelling of A380 aircraft

1. Jan 4, 2014

### Ehtisham501

Hi there,
I am currently a student at Heriot-Watt University and have been given a project of deriving a nonlinear equation of motion for an a380 wing engine. The engine is to be considered as a lumped mass attached to the cantilever beam and the main fuselage is considered having translational motion. Now, my question is in order to start with the derivation, how will my free body diagram of the engine and the airplane look like?

2. Jan 7, 2014

### AlephZero

You haven't told us what parts of the aircraft are included in your model, what loads you are considering, what the model is supposed to predict, and what parts of the model are "nonlinear". Probably, when you have the answers to those questions, it will be fairly obvious how to draw a FBD.

Two specific things:
1 You said the engine is modeled as lumped mass. Is "the cantilever beam" the engine pylon, or the aircraft wing?
2 There are two engines on each wing of an A380. Does your model include just one of them, or both?

FWIW my work involves modeling the way the dynamics of engines interact with the dynamics of aircraft, but from your vague problem description I have no idea what you are trying to do.

3. Jan 7, 2014

### Ehtisham501

The wing is considered as euler-bernoulli beam which is attached to the main fuselage and this fuselage is considered having translational motion. Both the engines are considered as lumped masses so basically a euler bernoulli beam having two lumped masses fixed from one end to the fuselage considered having only translational motion.
All i know is i am going to use the extended hamilton's principle for this where i first need to find the kinetic and potential energies taking into account geometric nonlinearity