TH-1H Finite Element Model Validation and Flight Loads Development

This paper presents the testing and analysis methods used in estimation of TH-1H flight loads and validation of a finite element model using data gathered during a static crane lift and flight strain survey. Analysis methods and results are emphasized here as most testing methods and data have been shared in previous forums. This is followed by a discussion of the resulting computed load values and their verification through comparisons to operational parameters such as aircraft weight and vertical acceleration. It was found that computed loads and moments compare well to flight conditions. For example, main rotor lift force correlates well to the product of aircraft weight and vertical acceleration (Nz). Preliminary results also show that the computed static and dynamic loads lead to strain predictions that have a good overall trend when compared to measured values, but more work is needed to improved correlations with individual sensors. Further development of these loads will allow the H-1 program office to use them to better address structural repairs, flight severities, and risk analyses. Accurately predicted aircraft response at the sensors from both static and dynamic inputs will enable the development of stress spectra to be used for durability and damage tolerance analyses and service life development.