Fakultät Maschinenwesen Professur für Dynamik und Mechanismentechnik Integration of measured receptance into a time domain simulation of a Multi Body Model using SIMPACK Dipl.-Ing. Johannes Woller Prof. Dr.-Ing. Michael Beitelschmidt Braunschweig,
Project presentation Cooperation between the TU Dresden and Bombardier Transportation GmbH Bombardier Center of Competence Railway Vehicle Engineering Integration Center (since 2007) Subsequent results are part of the research project: Topic: Project head: Employee responsible: Seamless integration of standardized Noise Vibration- Harshness (NVH) calculations in the development process of railway vehicle powertrains Prof. Dr.-Ing. Michael Beitelschmidt Dipl.-Ing. Johannes Woller Duration of the project: 4 years starting 2014 Integration of measured receptance into a time domain 2
Structure of the presentation Motivation New Approach Test models Final assembly based on measured data Conclusion Integration of measured receptance into a time domain 3
Motivation Airborne noise Interior noise Objective: Calculation of the interior noise of the rail vehicle caused by structure-borne noise from the drive train Unbalance, etc. Excitation of the railwheel contact Excitation of the electrical pulse pattern supply Gearing excitation Transfer of structure-borne noise through the bogie Integration of measured receptance into a time domain 4
Motivation Calculation of the structure-borne sound power transmitted to the car body (frequency domain): In Situ: Direct calculation of the coupled variables (with car body model) Structure-borne sound power: In Situ: Integration of measured receptance into a time domain 5
Motivation Structure borne sound: Forces and velocities must be calculated for all coupling points between the running gear and the car body Transfer characteristics of the car body is only considered via elastic body for comfort calculation (0-30 Hz) The current model approach is not valid in the higher frequency range FE modeling in this frequency range is not feasible Integration of measured receptance into a time domain 6
Structure of the presentation Motivation New Approach Test models Final assembly based on measured data Conclusion Integration of measured receptance into a time domain 7
Idea of using black box model Reduced Elastic car body Replaced by Black Box model based on measured data Coupling elements Model border Running Gear Integration of measured receptance into a time domain 8
General Approach: Black Box modeling in the acoustical frequency range Measurement System Identification Up to 2000 Hz Transform Simulation Black Box State Space Representation Integration of measured receptance into a time domain 9
Idea: Black-Box Sub model Use of force elements including Possible Approaches Co-Simulation (SIMPACK - Simulink) Using SIMPACK Force Elements Using FMU-Import in Simpack of Simulinkmodels Elastic body base on the floating frame of reference formulation transfer functions or state space representations 102,103 Force/Torque by Freq-Resp Transfer Function 1 :By Polynomial Quotient (max. 9 DGF) 141,142 State Space Filter 110, 123 Actuator Force Element Use of specialized force elements Dynamic Bushing/Hydromount Cmp 80 Air Spring Advanced 82 Non-linear Airspring 81 FlexiCoil-Springs 79 Shear Spring Implementation of a user element with dynamic transmission behavior Integration of measured receptance into a time domain simulation of a Multi Body Model using SIMPACK 10
Structure of the presentation Motivation New Approach Test models Final assembly based on measured data Conclusion Integration of measured receptance into a time domain 11
Proof of concept: Minimal models g Higher DOF m c b Simpack q Minimal MIMO-Model SIMPACK g m m c b q c b q m m c b q c q b m q c b Black Box Model Black Box Model c c m m q b q b Integration of measured receptance into a time domain simulation of a Multi Body Model using SIMPACK 12
Test Model constrained MDof estimated, without gravity Parameter Value m 100 kg Approximation as MDoF - Oscillator! " R % R % c 50000000 N m m b 1000 Ns m Reference model n 15 c n b q Sub model n8 m q R % c b m q c b Longitudinal vibrations in a rod (no bending) Integration of measured receptance into a time domain simulation of a Multi Body Model using SIMPACK 13
Estimation of a State Space Model Receptance Matlab System Identification Toolbox Tfest command (Matlab 2016b) (using 16 poles, 14 zeros) 10-4 10-5 Driving Point Receptance at q 8 Reference Estimated transfer function model receptance Tolerance: 0.01 Iterations: 1 (max. 50) Initialization Method: n4sid (modal subspace) Result: Number of poles: 16 Number of zeros: 14 Number of free coefficients: 31 Fit to estimation data: 100% Amplitude 10-6 10-7 10-8 10-9 10-10 0 50 100 150 200 250 300 350 400 450 500 Frequency in Hz Integration of measured receptance into a time domain simulation of a Multi Body Model using SIMPACK 14
Receptance / Mobility Coupling Force Element Joint with Degree of Freedom Black Box Model SSM-File 5 m * 1(z) Sensor Control Element Marker uf & 169 142 q & q' 5 m m + 1(z) Subvariable Excitation Constraint 85 1(z) Integration of measured receptance into a time domain 15
Receptance sub model: Frequency response function Dynamic behavior, Initial: non equilibrium state Frequency domain (Laplace Transformation) Time domain (numerical integration) F jω,f(ωt) Mobility: Response Respose From Black Reference Time Box Domain BlackBox Model Mobility: Respose Response From Black Reference Time Box Domain Reference Model Mobility: x 10x -3 From 10-6 Frequency Domain BlackBox Model Mobility: From Frequency Domain Reference Model 1.5-3 11.329 10-4 10-5 10 1.0 6.329 0.5 Response Mobility Time Domain Diagram 4, q, (jω),q, (t) m/ns -6 10 z [m/s] -7 10-8 10 0.0-3.671-0.5 1.329 Time Domain Excitation: Sine-Sweep 0 300 Hz in 500 s (0.6 Hz/s) -8.671-1.0-9 10 10-10-1.5-13.671 0 0 195 50196 100 197100 200 198 150 199 300 200 200 400250 201 202 300500 Frequency time time in [s] Hz[s] Integration of measured receptance into a time domain simulation of a Multi Body Model using SIMPACK 16
Structure of the presentation Motivation New Approach Test models Final assembly based on measured data Conclusion Integration of measured receptance into a time domain 17
Validation: Experimental test model Experimental-Analytical Dynamic Substructuring for Multi Body Simulation A.T. Moorhouse A.S. Elliott Integration of measured receptance into a time domain simulation of a Multi Body Model using SIMPACK 18
Reference model Source beam (running gear) X A B Y Timoshenko Beam models Tunable Coupling Stiffness Receiver beam (car body) Integration of measured receptance into a time domain simulation of a Multi Body Model using SIMPACK 19
FRF Measurement 4x4 FRF Measurement at Receiver Beam Excitation Impulse Hammer PCP 086C80 0,44g Response Polytec Laser Scanning Vibrometer PSV500 Suspension Resilient Mounting (rubber components) highest mounting frequency 23 Hz Lowest eigenfrequency 150 Hz Signal Processing Sampling Frequency: 5400 1/s FFT: 3200 FFT Lines Window Function: Force/Exponential Average: 3;complex Estimated Transfer function H1 Integration of measured receptance into a time domain 20
Insight model and measurement Receiver Receptance; db Reference= 10-6 m/n 100 From: In(1) To: q A x Magnitude (db) 50 0-50 -100 360 A B Phase (deg) 180 0-180 Timoschenko-Model Measured Receptance f_a x to q_a x -360-540 0 200 400 600 800 1000 1200 1400 1600 1800 2000 Frequency (Hz) Integration of measured receptance into a time domain 21
System Identification Matlab System Identification Toolbox n4sid command (Matlab 2016b) (modal subspace method) Initial States: 0 Estimated model order: 19 N4Weight: CVA Enforce Stability: on Result: 93959497 90829392 Fit to estimation data: % 93979692 94936887 To: q A x Magnitude (db) x y To: q B To: q A 50 0-50 -100 50 0-50 -100 50 0-50 From: f A x Receiver Receptance; db Reference= 10-6 m/n From: f A y Measurement Data Estimated Model From: f B x From: f B y -100 50 To: q B y 0-50 -100 0 1000 20000 1000 20000 1000 20000 1000 2000 Frequency (Hz) Integration of measured receptance into a time domain 22
Comparison in the frequency domain X A B Y Admittance Matrix Receiver (db Reference = 10-9 m/ns) Magnitude (db) y x y x To: q Y To: q Y To: q X To: q X 0-50 -100 0-50 -100 0-50 -100 0-50 -100 From: f X x From: f X y Reference 4x4 translational coupled measured estimation 0 500 1000 1500 20000 500 1000 1500 2000 Frequency (Hz) Eigenfrequencies of the 4x4 estimated from measurement 3000 2500 2000 1500 1000 500 paired Eigenfrequencies lower 95% deviation upper 95% deviation frequency fit 0 0 500 1000 1500 2000 2500 3000 Eigenfrequencies of the reference model Integration of measured receptance into a time domain 23
Structure of the presentation Motivation New Approach Test models Final assembly based on measured data Conclusion Integration of measured receptance into a time domain 24
First approach car body : Yaw Damper connection Car body: Triaxle acceleration measurement Yaw damper -150 From: In(1) Bode Diagram From: In(2) From: In(3) To: Out(1) -200-250 measured estimated Magnitude (db) To: Out(2) -300-100 -150-200 -250-150 To: Out(3) -200-250 10 1 10 2 10 3 10 1 10 2 10 3 10 1 10 2 10 3 Frequency (Hz) Integration of measured receptance into a time domain simulation of a Multi Body Model using SIMPACK 25
Outlook Challenges: Suitable measurement of the experimental test model Just looking at few connection points perfect measurement is needed System identification of MDof models Problems with strongly coupled structures Consideration of the mass properties of the substructure Extrapolation connection points with rotational DoF Integration of measured receptance into a time domain simulation of a Multi Body Model using SIMPACK 26
Advantages and Chances Chances: Combining linear acoustic models with Multi Body Simulation Looking at transient behavior instead of just steady state Using general sub models Not restricted to modal models Possible domain overlapping: Combining structure and airborne sound field using vibroacoustic transfer functions Significantly simplified representation of large weakly coupled structures Applications in other fields Extension to non linear sub models possible (using Functional Mockup instead of State Space) Integration of measured receptance into a time domain simulation of a Multi Body Model using SIMPACK 27
Thankyoufor your attention! Dipl.-Ing. Johannes Woller Wissenschaftlicher Mitarbeiter Technische Universität Dresden Fakultät Maschinenwesen Institut für Festkörpermechanik Professur Dynamik und Mechanismentechnik 01062 Dresden Tel.: +49 351 463-38042 E-Mail: johannes.woller@tu-dresden.de