Introduction to Aircraft Aeroelasticity and Loads

25

Ground Manoeuvre Loads

In this chapter, the treatment of ground loads will be outlined in a somewhat similar manner to that considered for flight manoeuvre and gust loads in Chapter 24. In the certification requirements (CS-25; Lomax, 1996), the load cases are essentially subdivided into the two categories of landing and ground handling, the latter covering taxi, take-off and landing roll, braked roll, turning, jacking, towing, etc. The calculations lead to airframe internal loads, together with landing gear ground, attachment and component loads; the methodologies are similar to those for flight loads except that discrete landing gear loads are also present. As per flight loads, an alternative subdivision would be into ‘bookcases’ (mainly ground handling) and ‘rational’ cases requiring flexible or quasi-flexible dynamic modelling (dynamic landing, dynamic taxi, dynamic braked roll, etc.). The calculation of stresses from internal loads (via loads acting upon components) and loads sorting will also be considered.

25.1 AIRCRAFT/LANDING GEAR MODELS FOR GROUND MANOEUVRES

As explained earlier in Chapter 17, the landing gears provide a vital function for landing and ground handling of the aircraft. Landing gears are highly nonlinear for the shock absorber, tyre and gear mechanism. A nonlinear gear model is required for all rationally based requirements, whereas bookcases may (in most cases) use a simpler model as their requirement is usually only to represent a reasonable static ...