Landing System Mass Reduction Through the Integrated Design of Landing Gear and Structural Attachments

The successful candidate will have the chance to study for a full time PhD. Sponsored by Safran, this studentship will provide a bursary of £14,000 plus fees for three years.
The aim of the study is to generate a methodology that permits the synthesis of landing gear solutions beyond the landing gear itself to include the attachment and other local structure. The approach will be used to account for variations in arrangement and positioning of structural attachments subject to a variety of realistic constraints. The sized landing gear will be added to assess the total landing gear system influence.

Overview:

Weight prediction methods for aircraft typically divide each section of the aircraft into separate entities that will use specific methods and tools to individually generate mass estimations. For the wing, mass estimation includes the wing master geometry and flight loads. For the landing gear, mass estimations can vary from a simple percentage of the MTOW to a more precise calculation based on the master geometries and ground loads. When all mass estimations of the different parts of the aircraft are combined there is a gap as the structural components linking the landing gears to the wing or fuselage are not accounted for. Although implications due to landing gear interfacing to the overall aircraft weight is not significant, it is nonetheless important in terms of promoting continuous improvements and for obtaining more precise weight estimations at aircraft level. Furthermore, there is lack of knowledge regarding how the positioning of the landing gear attachments affect the mass of the airframe mounted structure. For example, a lighter landing gear may result in a heavier solution at aircraft level due to larger or more complex attachments on the wing or fuselage. This project proposes to examine the implications of modifications to the landing gear attachments on the whole aircraft mass. In order to contain the study to a manageable level the scope will be limited to a wing mounted main landing gear with a rolling and folding single stay.

Aim:

To generate a methodology that permits the synthesis of landing gear solutions beyond the landing gear itself to include the attachment and other local structure. The approach will be used to account for variations in arrangement and positioning of structural attachments (pintles and side/dragstay) subject to a variety of realistic constraints. The mass of the sized landing gear will be added to assess the total landing gear system influence. This will result in a tool to size the attachment (and beyond) structure mass. A tool to size the gear itself may be developed or obtained from an existing source. The above process will be utilised to ensure sufficient robustness that it could be driven by a gradient based optimiser (though not necessarily within this study.)

In addition, the methodology should have provision to show the extent of mass sensitivity in relation to arrangements and positioning of structural attachments not reflecting a synthesised minimum mass configuration. Finally, a time history profile of the requisite actuation load corresponding to a given arrangement and positioning of structural attachments should be predicted.

Input:

A case-study serving to demonstrate the new methodology will be based upon known data associated with a baseline wing and MLG master geometry, including landing gear attachment pin sizes, bay volume and baseline ground loads.

Objectives:

• Define improved LG attachment structure geometry for various configurations.

• Research existing typical attachments for wing mounted LG at the pintle and stay interfaces.

• Generate idealised models for the attachments structure using topological improvement for baseline LG geometry then for incremental movements of the attachment points:

• Inbound and outbound along the rear spar for the side stay, including cardan pin and shackle type joints.

• Pintle axis movements in the 3 directions, while constrained by the clearance requirements of the retracted tires in the bay.

• Topological improvement must take into account the wing structure in order to improve the load path between the LG and the wing as well as the change in loads due to LG geometry incremental changes (pintle and stay attachments can be assessed independently).

• Design representative models and mass estimation method.

• Based on the topological models, create a preliminary design for the attachment brackets representative of manufacturable components.

• Derive a calculation method for estimating the delta mass of the structural attachment components as a function of displacement in positioning and/or any declared figures-of-merit.

• So given a specific design, we can chose a particular parameter and batch run a sensitivity study on this parameter.

• Actuation load time history output corresponding to a defined/synthesised arrangement and positioning of structural attachments.

• Intended optimisation code would use the NASA OpenMDAO platform (but may not be integrated within this study.).

• Application deadline18 Sep 2022
• Award type(s)PhD
• Start dateAs soon as possible
• Duration of award3 years
• EligibilityUK, Rest of World, EU
• Reference numberSATM307

This PhD may be suitable for someone with applied structural design experience relating to lightweight structures as applied to aircraft. This might include structural layout design, analytical and numerical analysis, Metallic and composite materials, structural stability etc. CATIA and FE skills will be useful.

Likely qualified to MSc level, practical work experience will be taken into consideration.

Sponsored by Safran, this studentship will provide a bursary of £14,000 plus fees for three years. 

Sponsored by Safran, this studentship will provide a bursary of up to £14,000 plus fees* for three years.         

Research students at Cranfield benefit from being part of a dynamic, focused and professional study environment and all become valued members of the Cranfield Doctoral Network.  This network brings together both research students and staff, providing a platform for our researchers to share ideas and collaborate in a multi-disciplinary environment. It aims to encourage an effective and vibrant research culture, founded upon the diversity of activities and knowledge. A tailored programme of seminars and events, alongside our Doctoral Researchers Core Development programme (transferable skills training), provide those studying a research degree with a wealth of social and networking opportunities.

For further information please contact: 

Name:   Prof Howard Smith
Email: [email protected]