REDESIGN OF AN AIRCRAFT ENGINE EQUIPMENT USING 3D DYNAMIC WHOLE ENGINE MODEL Company: SNECMA MOTEUR Engineering System Integration Division Author: Alain Mazelet

Redesign of an aircraft engine equipment using 3D dynamic whole engine model 7, 8 & 9 juin 2000 page 2 MSC :Réunion Technologique Europe du Sud Background of the study Baseline engine in service New application implies modification of one or more equipments Impact of these modifications on engine carcass integrity is not a concern Main concern is local impact around equipment Need to assess if local redesign is required to comply with blade out regulation WEM model is used to redesign equipment without blade out test

Redesign of an aircraft engine equipment using 3D dynamic whole engine model 7, 8 & 9 juin 2000 page 3 MSC :Réunion Technologique Europe du Sud Calculation process for the base line equipment Forced response test data Bladeout test data WEM Simplified equipment model Forced response calculation Bladeout calculation Detailed equipment model Correlation Interface acceleration Correlation Stress analysis Equipment designer SNECMA: Integration division SNECMA: Test division

Redesign of an aircraft engine equipment using 3D dynamic whole engine model 7, 8 & 9 juin 2000 page 4 MSC :Réunion Technologique Europe du Sud Calculation process for the modified equipment Vib. survey test data WEM Simplified equipment model Correlation Bladeout calculation Detailed equipment model Interface acceleration Stress analysis Equipment designer SNECMA: Integration division SNECMA: Test division Vib. survey calculation

Redesign of an aircraft engine equipment using 3D dynamic whole engine model 7, 8 & 9 juin 2000 page 5 MSC :Réunion Technologique Europe du Sud Equipment models Simplified model enables general loads and displacement calculation: beam / shell / masses / springs / rigid bodies Detailed model enables stress analysis: volume elements model Equipment

Redesign of an aircraft engine equipment using 3D dynamic whole engine model 7, 8 & 9 juin 2000 page 6 MSC :Réunion Technologique Europe du Sud Forced response test Equipment is mounted on fan frame and fan case to get adequate boundary conditions White noise excitation is produced with a dash pot ( Hz) 83 dofs are measured on the structure with accelerometers 57 modes are detected, we focus on 17 which were more representative of equipment displacement F

Redesign of an aircraft engine equipment using 3D dynamic whole engine model 7, 8 & 9 juin 2000 page 7 MSC :Réunion Technologique Europe du Sud Forced response test / model correlation Correlation parameters: mount stiffness, flange stiffness, masses and inertia … Correlation method: MAC / FDAC for deform shape correlation, FRF comparison for each accelerometer. Good correlation was achieved between 30 and 150 Hz Test model v75 (soft mounts) Test model v82 (stiff mounts) Test model v3 (first model) Test detailed model (volumic)

Redesign of an aircraft engine equipment using 3D dynamic whole engine model 7, 8 & 9 juin 2000 page 8 MSC :Réunion Technologique Europe du Sud Whole engine blade out model Whole engine and test rig model (shell, beam, masses, rigid bodies …) NASTRAN V69.1 (SOL109) + DMAP alter for gyroscopic effect Non linear element between fan and fan case dofs (11000 after condensation) Loads: unbalance load (one blade), impact of the blade on the fan case, decrease of thrust load, and deceleration moment.

Redesign of an aircraft engine equipment using 3D dynamic whole engine model 7, 8 & 9 juin 2000 page 9 MSC :Réunion Technologique Europe du Sud Blade out test / model correlation bearing load Equipment acceleration Equipment link load calculation test

Redesign of an aircraft engine equipment using 3D dynamic whole engine model 7, 8 & 9 juin 2000 page 10 MSC :Réunion Technologique Europe du Sud Equipment design Bladeout calculation with simplified equipment model Interface acceleration Stress analysis PROCESS Run blade out transient calculation Extract engine / equipment interface acceleration Run detailed equipment transient response under enforced interface motion (Lagrange multiplier method or big mass method) Conduct stress analysis SNECMA Moteur does not need to export WEM, DMAP etc … Equipment designer does not need to export detailed model SNECMA and equipment designer do not need to have the same FEM code, no translation is needed Detailed equipment model t a t a t a

Redesign of an aircraft engine equipment using 3D dynamic whole engine model 7, 8 & 9 juin 2000 page 11 MSC :Réunion Technologique Europe du Sud CONCLUSION WEM gives a satisfactory representation of the engine behaviour Engine equipment design can be achieved with dynamic transient criteria, static equivalent criteria are not used anymore. Data exchanges between SNECMA and equipment designers are limited to interface acceleration MSC/NASTRAN + DMAP solutions give us the capacity to run the whole process: including condensation, non linear elements, stress analysis...