A major global engineering services provider awarded my team a simulations project they had secured on a turnkey basis from IGCAR (Kalpakkam, Tamil Nadu, India). This project had to do with assessments of frequency responses in a helicopter- borne TDEM antenna. The underslung toroidal antenna assembly, of fibre- composite material would hang several meters below the helicopter, through a system of nylon bungee cords. Nylon has a significantly non- linear deformation character under loading. For our simulations accordingly, simple tests were done in order to freeze onto an appropriate modulus of the bungee cord, in the neighborhood of the design dynamic load. Interestingly, the bungee cord's aeroelastic, particularly galloping behaviour, could significantly influence the antenna dynamic performance. However, guided by legacy design and collective experience of IGCAR, the bungee cord's aeroelastic response was excluded as being infeasible under the conditions of flight.

My team successfully went from finite element modelling through many NASTRAN simulations to understand the design performance, supported by hand estimates for sanity checks where possible. Simulations, largely routine ones, covered modal frequency response and buckling of various subsystems of the assembly.  Regular face- to- face reviews were held with IGCAR and the services provider groups and the final report delivered in Jan 2018.

The report's images and data are non- disclosable.