David Ehrhardt Email & Phone Number

Monticello, Il, Us

Urbana-Champaign Area

Urbana-Champaign, Illinois Area

Project lead in the measurement of curved panels subjected to temperatures near 1000 °F with combined acoustic and mechanical loading using 3D-DIC and forward looking infrared cameras. Project lead in the design and manufacturing of a nonlinear beam demonstrator with distributed and localized nonlinearity.Part of a team measuring flow over curved rigid panels and flat compliant panels in Mach 4 flow using high speed Schlieren techniques, temperature sensitive paint, and 3D-DIC.

Wright Patterson Air Force Base

Part of a team measuring shockwave boundary layer interactions of compliant panel in Mach 3 flow including full-field pressure, temperature, and displacement measurements.Experimental identification of snap-through boundaries of buckled beams and plates in combined thermal/mechanical environments.Measurement and modeling of nonlinear normal modes of bi-stable systems.

Bristol, United Kingdom

Responsible for design and testing of nonlinear structural system with 1-1 nonlinear modal interactions.Used normal forms analysis to understand the effects of nonlinear interaction terms on the modal response of structuresIdentifying the nonlinear resonant responses of the structureApplying identification techniques to find nonlinear parameters from experimental dataFocusing on torsional/bending motions in cantilever beams

Madison, Wisconsin Area

Measured nonlinear normal modes of beams and plates using stepped sine base excitation and force appropriationUsed 1200lbf-50lbf shakers and modified magnetic pickups to provide steady state and swept sinusoidal, random, and impulse loading excitation.Numerically computed nonlinear normal modes of reduced and full order finite element models using numerical continuationMeasured linear natural frequencies, mode shapes, frequency-energy backbone curves, and deformation patterns of beams and plates using 3D digital image correlation and continuous-scan laser Doppler vibrometryCompared and updated finite element model with measured full-field dynamic responses

Madison Wisconsin

Lead weekly discussions in Statics and Dynamics coursesGraded exams and design reports

Stoughton, Wisconsin

Performed Order Analysis on exhaust pressure pulsation test dataAided in 26000 lbf and 100 lbf electrodynamic shaker installation and maintenance Wrote testing procedure check lists for 26000 lbf shakerPerformed modal tap test in field on exhaust component

Conducted experiments on variables used to calibrate a 3D DIC systemAssessed calibration error using known displacementsConducted swept sine vibration experiments on curved beam (50-900 Hz)Measured full field deformation of curved beams using 3D DIC coupled with high speed cameras using AramisExtracted and analyzed Aramis data using MATLAB

Supervised experiments in Thermodynamics and Mechanical VibrationsWrote pre-labs for student use during experimentBuilt and tested experimental setups for lab useAnalyzed data from testing to determine usefulness of lab

Project: Identification of Nucleate Boiling in Heat Exchangers Advisor(s): Dr. David Zietlow, Prof. Steve Gutschlag Tasks: Conducted experiments of heat exchangers Conducted maintenance on apparatus Analyzed data to determine nucleate boiling Researched possibilities for next stage of testing

Detailed drawings in Pro-Engineer Checked drawing done by other Engineers Organized parts to be delivered to client Managed office re-organization

Doctor Of Philosophy (Ph.D.), Engineering Mechanics

Master Of Science, Mechanical Engineering

Bachelor Of Science, Mechanical Engineering

Master'S Degree, Mechanical Engineering