Lecture Notes: PASCO Scientific Material Testing Apparatus

Presenters

• Chong
• Justin, Mechanical Engineering Student, California State University Sacramento

Overview of Material Testing Apparatus

• PASCO Scientific's material testing apparatus
  • Manual crank connected to an encoder
  • Encoder connected to a lead screw with a carriage
  • Carriage allows attachment of material sample
  • Equipped with a force sensor for measuring material properties in compression and tension

Included Components

• Material testing apparatus
• Safety guards (no need for safety glasses)
• Calibration test piece for software calibration
• USB link for connection to a laptop
• Single user license of Capstone software for data analysis
• Starter kit for immediate setup

Additional Accessories

• Shear accessory
• Bending accessory
• Flat coupon adapter
• Adapters for structure kits and testing on structure beams

Materials for Testing

• Nailed steel, regular steel, brass, aluminum
• Two types of plastic (clear plastic with polarizing lens)

Demonstration Setup

• Remove safety cover
• Use brass piece from starter kit
• Set up webcam for test sample filming
• Hardware setup in Capstone software
  • USB link and webcam connection
  • Configure material testing unit
  • Switch sign for tensile test travel direction

Calculating Stress and Strain

• Stress equation: Stress = Force / Cross-sectional area
  • Test sample diameter: 3.3 mm (converted to meters for consistency)
  • Test sample length: 35 mm
• Enter equations into Capstone software using Calculator
  • Stress in SI units (Pascal) and imperial units (PSI)
  • Strain: Strain = ΔL / L (unitless)

Data Collection and Analysis

• Record movie with synchronized data
• Use Capstone to display video and graph simultaneously
  • Stress on one axis, strain on the other
  • Adjust graph view for clarity
• Zero the sensor before data collection
• Collect data by cranking manually
  • Observe elasticity, plasticity, and yield points
  • Playback recorded video for review

Additional Experiments

• Hysteresis demonstration: explore plasticity and elasticity
• Show work hardening

Closing

• Thanks to Justin and audience for participation
• Encourage further exploration of apparatus capabilities