Sandia M.A.S.T. Miniature Automated Shock Tester TEAM PICTURE HERE Nicholai Olson, Cameron Hjeltness, Travis Nebeker, Michael Brewster, Fernando De La Garza Client:Dr. Scott Whalen - Sandia National Laboratories Faculty Advisor: Dr. Steve Beyerlein Graduate Student Mentor: Kysen Palmer

What is a Shock Tester? Used for testing hardware under impact loading conditions Come in different sizes for testing a variety of objects Typically use pneumatics, gravity, electric actuation

Background Dr. Whalen – Sponsor and Client – Needs personal, bench-top sized test apparatus – Measuring shock levels on small electronics – Safety conditions exist – Lab constraints

Unlimited access to a personal tester reduces design cycle time Smaller apparatus than commercially available High accuracy ensures design reliability Specific design constraints are tailored toward the specific needs of Dr. Whalen. Benefits of this Project

Project Targets Measure shock of magnitude 100g to 200g – Haversine waveform required Maximum dimensions: 30” W x 30” L x 72” H – Smallest possible design preferred Device under test (DUT): D = 5 cm L = 8 cm M = 0.3 kg – Fixture to conform to Sandia standard bolt pattern LabView software used to collect data Safety shields and safety mechanisms to be installed

Morphological Chart STRUCTURAL FOUR POST VERTICAL TWO POST VERTICALSINGLE POST NO VERTICAL STABILIZATION REDUCTION OF ENERGY LOSSBEARINGSBUSHINGSNONE TABLE LIFT ACTUATION CABLE & WINCHACME SCREWLINEAR MOTOR ROTARY MOTOR AND BELT SYSTEMNONE RELEASE MECHANISM ELECTRONIC CLUTCH SOLENOID & PIN MOTOR CONTROLS ELECTRO- MAGNET NONE EXTERNAL SOURCE OF ACCELERATION SPRINGS/ ELASTIC MATERIALS ROTATIONAL HAMMERLINEAR MOTOR ROTARY MOTOR AND BELT SYSTEMSOLENOID NONE (GRAVITY)ELECTRIC RAM METHOD TO VARY LEVEL OF SHOCK VARIABLE ELASTIC INPUT STIFFNESS DROP FROM VARIOUS HEIGHTS MOTOR/SOLENOI D CONTROLS VARY STIFFNESS OF BASE ENERGY DISIPATION (After impact) VISCOELASTIC DAMPERS LOCKING MECHANISM MOTOR/SOLENOI D CONTROLSSOLENOID ELECTROMAGN ETIC STOPPER/LIFT CONTROLS LINEAR ENCODER CONDUCTIVITY IN COLLISION INDUCTANCE BASE VELOCITY SENSING

Prototype Development Slide Rails Galvanized Steel Pipe Construction Accelerometer and DUT Mounting

Prototype Goals Verification of design calculations Debug accelerometer & hardware Develop data acquisition program

Large frequency range (upper end ~10 [kHz]) Data filter included within the unit Small form-factor Resists influences by temperature changes Relatively low price (Under $1,300.00) Accessories included Accelerometer Target Values

Accelerometer Purchased Triaxial AccelerometerX-Y-Z Outputs and Constant Current Inputs PCB Piezotronics Model 356A24 – 500 g peak acceleration measurement – Hz Frequency Range

Structural Considerations Four Post – Stable – Possible galling – High cost – Machining time Two Post – Low chance of galling – Medium-Low cost – Requires higher strength material

Reduction of Energy Loss Bearings – Less friction – Higher cost Both options may be viable. Bushings – More friction – Lower cost

Viable Design Options Option B: ACME Screw Actuation Option A: Linear Motor / Solenoid

Table Lift System Solenoid – Medium cost – Easily Programmable Linear motor – High cost – High difficulty of Programming Both – Accurate and repeatable – Simplify system ACME Screw – Strong – Low cost and high reliability – Low repeatability Option B:Option A:

Release Mechanism Solenoid and Pin – High Cost – High Safety – Difficult control system Magnetic Release – Works with ACME screw idea – Requires dual control to re-couple No release mechanism needed Option B: ACME Screw Option A: Linear Motor / Solenoid

Downward Acceleration Linear Motor /Solenoid – Variable Force Input – Very Controllable Gravity – No cost – Longer travel required Springs/Elastic – Low cost – Workable area reduced Option B:Option A:

Post-Impact Energy Dissipation Viscoelastic Dampers – Typically Low cost – Easy to install/vary Locking Mechanism – Fast stop – May cause ringing – Increased machining time Solenoid – Medium cost – Highly controllable Electromagnetic Stopper – Easily Programmable – Medium cost – May cause ringing Option B: ACME Screw Option A: Linear Motor / Solenoid – Controls can be reversed to prevent ringing

Method to Vary Shock / Waveform Variable Elastic Stiffness – Springs in parallel – Increase Spring Constant Acceleration at Impact – Vary Drop Height – Change force input – Few components required Vary Stiffness of base – Changing modulus of elasticity – Adding or subtracting material can change pulse length and wave form. A combination of these may be used.

Next Steps Develop data acquisition program Prototype testing Develop detailed design Purchase components Fabrication Testing and validation Deliver finished product to Dr. Whalen