Building this mechanical spectrometer was part of my thesis project. The objective was to design and build a testing apparatus capable of dynamic mechanical analysis, or DMA, through forced constant amplitude at fixed or variable frequency compressive oscillation, according to ASTM D4065. Building this apparatus was necessary to determine the tan(δ), or loss tangent, of a novel form of energy absorbing composite material at various temperatures and frequencies.
•LabVIEW DAQ and Sound and Vibration Toolkit
•MATLAB coding for analyzing large data sets
•SPSS for finding significant factors in the data
•Proper lathe, milling, tap and die operation
Sensors and Actuator Components
•24 VDC motor through a DC power supply
•IronHorse GSDI-48 PWM speed control unit
•TE Connectivity MHR-250 linear variable displacement transducer (LVDT)
•TE Connectivity LDM 1000 signal conditioner
•PCB 208C02 force sensor
•NI 9215 module with NI Sound and Vibration Toolkit for data collection
•Steel stock and aluminum T-slotted framing, various bearings and shafts
Temperature Control Components
•Heating element from a miniature crock-pot
•Uniclife UL80 aquarium pump for cycling isopropanol cooled with dry ice.
The apparatus is capable of DMA at frequencies between 25 and 100 Hz at temperatures between 0°C and 50°C. Calibration and verification of accuracy was accomplished by performing DMA on various durometers of Sorbothane. Data gathered with this system will be published in Composite Structures.