Engineering Analysis: structural dynamics/vibroacoustics/stress
Resume:
Longjun Liu, PhD, FE/EIT, US citizen
Structural Dynamic/Vibroacoustic/Vibration/Stress/Fatigue/Optimization Analyst & Researcher
**********@*****.***, 971-***-**** (home), Yorktown, VA 23693
Expert on mechanical structure analysis, testing, and design: loads, dynamics, vibration, vibroacoustic, stress, fatigue/fracture, sloshing; metal, composite, viscoelastic material; design optimization, statistical analysis; launch vehicles, spacecrafts, solid motors, liquid engines, aircraft engines, other vehicles or equipment; tests: fatigue, vibration (sinusoidal, random), modal, engine, acoustic, pyroshock, viscoelastic, wind tunnel
Nominated for technical leadership award at NASA/MSFC/Space Systems Department. Awards for random vibration, fatigue analysis, etc. Award for successful team work.
SKILL SUMMARY
Structural dynamics
Finite element analysis
Dynamic analysis: transient, harmonic, random vibration
Multibody dynamics: vehicle vibration simulation and control
Loads & dynamics
Coupled load analysis (CLA)
Bending modes analysis
Superelements/Craig-Bampton models
Liquid sloshing modeling and analysis
Monte Carlo analysis
Modal testing and analysis
Vibroacoustic, flow induced vibration
Buffet forcing function definitions based on wind tunnel tests
Aerodynamic load definition, in-flight fluctuating pressure
SEA (statistical energy analysis) of launch vehicles
BEM (boundary element modeling and analysis)
Electric equipment/instrument isolation
Vibration control (isolation, dampers, neutralizers, absorbers, detuning, decoupling, etc.)
Vibration data acquisition and analysis
Composite analysis and design
Viscoelastic material testing and analysis
Stress analysis: linear, nonlinear
Buckling analysis
Contact analysis
Fatigue, fracture mechanics
Testing: Aircraft engine, modal, fatigue, random vibration, acoustic, pyroshock, rubber characterization
Optimization: structural optimization, Operations research, genetic algorithm,
Statistics:
DOE (Design of experiments), Response surface methodologies, DACE (Design and analysis of computer experiments, Statistical process control, Statistical Signal Processing, general statistical analysis
Products: Aircraft engines, space vehicles, launch vehicles, solid motor and liquid engine, spacecraft, railcars
Materials: metal, composite, viscoelastic material, wood (total anisotropic, 21 parameters)
Tools: FEA: NASTRAN, ANSYS, ABAQUS, FEMAP, PATRAN,
SEA: VA ONE, WAVE 6,
CAD: NX, SOLID EDGE, AUTOCAD
MATLAB, MATHCAD, CAM,
SAS, SPSS
NeuralWorks, NUCARS, VISUAL C++, DAKOTA
Programming languages: MATLAB, PYTHON, ANSYS(programming), CAM, FORTRAN, LISP
EXPERIENCE
1. Aerospace Engineer, Structural Dynamics and Vibroacoustics, NASA LaRC, Hampton, VA, 1/2017-12/2017
Couple load analysis of Space Launch Systems (SLS) with PYTHON and CAM codes
Buffet forcing function (BFF) definition based on wind tunnel (WT) tests with MATLAB for SpaceX
Provided a formal review for SLS BFF definition based on WT and research plan to significantly improve the methods
2. Senior Structural Dynamics Engineer, Vibroacoustics and dynamic environment, Virgin Galactic, 5/2016-10/2016
Buffet forcing function definition based on wind tunnel test data and correlation length from coherence decay
Created new zoning rules for aeroacoustic vibration analysis, provided effective methods to calibrate and validate
Statistical Energy Analysis (SEA) of a launch vehicle’s response to acoustic excitation with Wave6; FEA: NASTRAN
3. Staff Engineer, Aeroacoustic vibration/structural dynamics /stress/fatigue, Pratt & Whitney, 5/2011-4/2016
Lead aeroacoustic vibration methods, created a real breakthrough for zoning and PSD scaling, matching test results
Structural analysis, static/dynamics, harmonic/random vibration, stress, fatigue, fracture mechanics, with ANSYS
Static/rotating structures, compressor blade/rotor analysis, turbine rotor lifing based on fatigue & fracture mechanics
Post-test analysis with modal superposition: created new methods and matched engine test results; MATLAB for codes
Engine test online monitoring, noise detection and data validation, and digital signal processing
Modal testing and analysis: mode extraction, damping estimate, FEA matching tests (harmonic and random vibration)
Tools: created codes and GUI to combine MATLAB and ANSYS for fracture screening, compiled for Windows Linux
4. Senior Dynamics Engineer, NASA/MSFC (Marshall Space Flight Center), ESTS group, Huntsville, AL, 8/2009-4/2011
Dynamic analysis and testing for launch vehicles and spacecraft, stress, FEA with FEMAP NASTRAN PATRAN
Random vibration loads, aeroacoustic loads, transient loads, satellite structural analysis (LADEE)
Generated vibration test criteria for acceptance and qualification tests; wire rope isolator simulation
Random vibration tests of computers, instrument units, etc., pyroshock tests, acoustic tests; MATLAB for codes
In-flight fluctuating (TBL: turbulent boundary layer and shock) pressure analysis and definition
Wind tunnel and flight test data analysis and comparison with analytical/empirical predictions
Programs: Ares I, Minotaur V and LADEE lunar spacecraft, EELV/Atlas V/XPC, etc. solid modeling with Pro-E
5. Principal Dynamics Engineer, Orbital Science Corporation, Chandler, AZ, 5/2007-7/2009
Launch vehicle loads and dynamic analysis: bending modes, coupled load (CLA), with FEMAP and NASTRAN
Loads: liftoff, transonic, max q-alpha, wind, gust, vortex shedding, thrust, TVC, drag, buffet; material: metal,composite
Craig-Bampton models and superelements; provided support for pogo analysis; solid modeling with Solid Edge
6. Dynamics Engineer, ATK Launch Systems, Promontory, UT, 9/2005-4/2007
Dynamic/vibration analysis and testing, stress analysis, using ABAQUS, NASTRAN, and MATLAB
Viscoelastic material characterization via testing and simulation, close FEA and test match for dynamic stress & strain
Nonlinear FEA of viscoelastic and hyperelastic material with ABAQUS, harmonic and random dynamic ones
7. Senior Design Engineer, Gunderson Inc., Portland, OR, 2/1996-8/2005
Structural design, linear and nonlinear stress analysis, buckling analysis, fatigue analysis, CAD with Solid Edge
Dynamic/vibration analysis, multi-body dynamic modeling and motion control, dramatically reduced vibration
Composite analysis and design; structural optimization (removed 36% weight); FEA with FEMAP NASTRAN
EDUCATION
Ph.D. Systems Science, Optimization of Mechanical Structure Systems, Portland State University
MS in Engineering Management, Portland State University
MS in Structural Engineering, Southwest Transportation University
BS in Mechanical Engineering, Northern Transportation University
License: FE/EIT (76888EIT, OR); Certificates: Vibroacoustic, SEA/BEM analyses, General fluid system simulation
FEA, SEA, BEM; NASTRAN, ANSYS, ABAQUS, FEMAP, PATRAN, VA1, WAVE6; NX, SOLID EDGE; MATLAB
American Institute of Aeronautics and Astronautics (AIAA), American Society of Mechanical Engineers (ASME), Society for the Advancement of Material and Process Engineering (SAMPE), ASM, SME, …
Detailed resume: http://www.indeed.com/r/06df67fe0036fd39, **********@*****.***
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