Joints Workshop Vibration and Turbomachinery

Transcription

1 Vibration University Technology Centre Joints Workshop Vibration and Turbomachinery Muzio M. Gola Professor of Machine Design Team leader LAQ AERMEC DIMEAS -POLITO C. Schwingshackl Lecturer in the Dynamics Group Vibration University Technology Centre Mechanical Engineering Imperial College London

2 Theoretical research Vibration University Technology Centre Development of nonlinear tools - Friction contact elements - Bifurcation and instability - Graphical user interfaces Application to aircraft engine - Methodology - Response behaviour Validation - Against experimental data Schwingshackl 2

3 Experimental research Vibration University Technology Centre Basic research - Friction contact behaviour Nonlinear structural damping - Engine components Blade root Under platform damper Flange - Rotating and stationary systems Measurement techniques for nonlinear behaviour - Large amplitude excitation - Data processing Schwingshackl 3

4 loss factor [%] Receptance [mm/n] An example of our current work: Nonlinear flange joint analysis Vibration University Technology Centre Flange and bolt locked - Amplitude control 7.00E E E E E E E E Frequency [Hz] locked 1g - ori 0.1g - 1+1Mpa 1g - 1+1MPa 10g - 1+1MPa 100g - 1+1Mpa 1000g - 1+1Mpa 0.02g 100g 500g 2000g 4000g 1.00% 0.80% 0.60% 2T damping - updated model 0.40% 0.20% 0.00% Measurement Simulation Response level [g] Schwingshackl 4

5 Main problem areas Vibration University Technology Centre Overall dynamic response of structure - Effect of joint on stiffness and damping Need for robust prediction methods - Macro level - Variability of joints - Contact conditions unknown Designing joints that are insensitive - Manufacturing tolerances - Wear Industrial environment - Damper design has matured and is routinely used - Focus is shifting to new joint types large models Schwingshackl 5

6 What needs to be done Vibration University Technology Centre Robust tools for joint analysis - Fast and reliable - Large scale modelling Too much detail may get in the way - Change over time Criteria for effective joint design - Don t deal with it, use it Nonlinear friction joint validation - Which parameters? - Level of validation Global or local response Novel test methods - Operational level testing - Data processing Schwingshackl 6

7 forza di contatto tangenziale: F t (N) Politecnico di Torino Contact mechanics and tribology Sliding wear tests in vibration Overview of requests from companies / european projects (funding) Damper mechanics and wear Supporto Left: cicli isteresi i=2n i=n i=n/ Spostamento relativo: du (m) x 10-5 Contact modelling on rotating components Turbine and gear dynamics (flutter, mistuning) Damping and wear assessment on blades Schwingshackl 7

8 Contact mechanics and tribology Overview of capabilities Damper mechanics on dedicated test rigs and on rotors Contact modelling on rotating components Turbine and gear dynamics & damping Schwingshackl 8

9 Normalized Amplitude Amplitude (m) Politecnico di Torino Friction LAQ AERMEC Poli.Contact: Non-linear Simulation Code Poli.Shroud Poli.Damper Frequency (Hz) Poli.Root Poli.Gear No ring damper 5% nom. mass 10% nom. mass 25% nom. mass 50% nom. mass nom. mass 200% nom. mass 400% nom. mass Schwingshackl Frequency (Hz) 0

10 Friction LAQ AERMEC Validation of Contact Models: High Temperature Test Rig No. 1 du relative displacement (LDV) N (dead weights) T tangential force measurement Working range: Temperature : C Displacement: 0,1 m m Normal loading: 1kg a 10kg Excitation frequency: 1-100Hz Schwingshackl 10

11 Friction LAQ AERMEC Validation of Contact Models: High Temperature Test Rig No. 2 Mechanism for tilting approach Cell pre-loading & specimen loading Test Frequency: Hz; Relative motion range μm Temperature up to 1000 C Overall force measurement error : ~ 0,7% Overall displacement measurement error: < 1% Feedback control of the test conditions (temp. & displ.) Schwingshackl 11

12 Z [ m] Politecnico di Torino Friction LAQ AERMEC Validation of Contact Models: Wear Measurements Inconel T800 coated initial geometry E6 cycles -35 plane, worn profile, numerical plane, 90 direction of motion -40 plane, direction of motion a plane, initial profile, numerical X, Y [mm] M152 steel Schwingshackl 12

13 Validation of Contact models (blade/root joints) Numerical Contact Model Friction LAQ AERMEC The Test Rig T 1 T 2 N 1 N 2 Numerical results Experimental results Schwingshackl 13

14 Friction LAQ AERMEC Development & Validation of Damper Models The underplatform damper is a free body pressed against the blade platforms by centrifugal force. Damper models are necessary to simulate the complex damper kinematics. 1 Through damper response Two-Blade Test Rig stick Schwingshackl 14

15 Friction LAQ AERMEC Development & Validation of Damper Models 6 2 Through hysteresis cycle damper force and kinematics measurements Schwingshackl 15

16 Friction LAQ AERMEC vacuum chamber Rotating Rig 800 mm telemetry system (12 channels) Full scale tests & mistuning Static Rig underplatform dampers & shrouds non contact magnetic excitation Test disk diameter up to 650 mm Rotation speed up to 4000 rpm rotati ve seal motor containm ent ring non-contact rotating excitation by electromagnets Schwingshackl 16

17 Vibration University Technology Centre Some other considerations How to determine which problems to tackle - Experience and discussions within the institution - Good understanding of the needs from industry - Conferences and this workshop Who will use your research? - Strong industrial focus - Rolls-Royce, AVIOGroup, GE-NP, ANSALDO? Where is the funding coming from? - Industrial partner directly - Government/Industry partnership - European Projects Schwingshackl 17