A Practical Method for Aircraft Life Enhancement
Abstract
The purpose of this Phase I effort was to prove the feasibility of reducing dynamic loads induced into aircraft structure by increasing landing gear strut precharge pressure. Reducing dynamic loads will reduce fatigue damage to aircraft structure resulting in life extension and reduced maintenance and inspections. An additional purpose of this effort was to determine the "degree" of life enhancement that can be achieved. Finally, commercial aircraft operations and maintenance organizations were contacted to determine the level of ground loads related problems that occur in day to day operations. A NASA Langley instrumented A-6 main landing gear strut was used to experimentally validate the concept. Computer simulations were used to predict dynamic load reductions for a large matrix of conditions for a variety of aircraft. The computer predictions were used to assess the potential life enhancement that could be achieved. Questionnaires were sent to a variety of commercial airline organizations requesting information regarding maintenance, inspection and structural failure data that relate to this effort. Phase I of this effort proved conclusively (both analytically and experimentally) that ground loads can be reduced by 40% or more by increasing strut precharge pressure. Estimated improvements in life of up to 15% were calculated for a randomly selected structure. A "hot spot" would show much greater improvement. The results of Phase I were better than anticipated. The application of this technology will include military and civilian aircraft. The aircraft that will benefit the most will be large flexible aircraft such as commercial jets and military bomber and cargo aircraft that operate heavy and on rough runways.
Document Details
- Document Type
- Technical Report
- Publication Date
- May 01, 1998
- Accession Number
- ADA362642