High Strain Rate Infrastructure

Tensile Hopkinson Bar

This apparatus is capable of testing a variety of materials ranging from aerospace grade titanium to automotive grade aluminum. Special grips have been incorporated to allow sheet specimens to be tested with minimal wave distortion. The momentum trapping ability allows the test to be interrupted at predetermined strain levels. This ability combined with different striker lengths (and hence test duration) is useful when doing damage characterization. Custom software was developed to analyze the raw voltage data and convert it into representative stress, strain and strain rate curves.

tensile hopkinson bar

Specifications:

  • Strain Rate Regime: 1000s-¹ to 1500s-¹
  • Temperature Range: Up to 300ºC
  • Bar Lengths: 1.4 m
  • Striker Lengths: Up to 300 mm
  • Bar Material: Hardened Steel
  • Instrumentation: Two half Wheatstone bridges utilizing 1000 ohm semi-conductor gauges
  • 8 channel Natoinal Instruments Data Acquisition PXI system capable of sampling up to 60MHz
  • Laser velocity detection for striker
  • Momentum Trapping for doing interrupted test samples
  • Gas Gun actuated for enhanced velocity control
  • 100,000 fps high speed video

Compressive Hopkinson Bar

This apparatus is capable of compression testing a variety of materials ranging from D2 tool steel to some biological materials such as bone. Specimens can also be fabricated in such a way that high rate shear properties can be obtained. Custom software was developed to analyze the raw voltage data and convert it into representative stress, strain and strain rate curves.

compressive hopkinson bar

Specifications:

  • Strain Rate Regime: 500s-¹ to 3000s-¹
  • Temperature Range: Up to 300ºC
  • Bar Lengths: 0.685 m
  • Striker Lengths: Up to 300 mm
  • Bar Material: Hardened Steel, Aluminum
  • Instrumentation: Two half Wheatstone bridges utilizing 1000 ohm semi-conductor gauges
  • 8 channel Natoinal Instruments Data Acquisition PXI system capable of sampling up to 60MHz
  • Laser velocity detection for striker
  • Gas Gun actuated for enhanced velocity control
  • 100,000 fps high speed video

Polymeric Compressive Hopkinson Bar

This apparatus is capable of testing a variety of softer materials such as silicon rubber, polyurethane foam and muscle tissue. Custom software was developed to analyze the raw voltage data and convert it into representative stress, strain and strain rate curves while accounting for wave dispersion and attenuation due to the bar's inherent rheological properties.

polymeric compressive hopkinson bar

Specifications:

  • Strain Rate Regime: 500s-¹ to 1500s-¹
  • Bar Lengths: 2.4 m
  • Striker Lengths: Up to .7 m
  • Bar Material: Aluminum, Acrylic, Low Density Polyethylene
  • Instrumentation: Two half Wheatstone bridges utilizing 1000 ohm semi-conductor gauges capable of sampling up to 20MHz
  • Laser velocity detection for striker
  • Gas Gun actuated for enhanced velocity control
  • 100,000 fps high speed video

Gas Gun

This apparatus is used to test high rate impact testing of composite materials as well as Taylor specimens. The relatively large barrel diameter in combination with differing sabots allows projectiles of a variety of dimensions to be used.

gas gun

Specifications:

  • Barrel Length: 3.7m
  • Barrel Diameter: 14 mm
  • Maximum Operating Pressure: 10 000 psi
  • Instrumentation: Laser velocity detection for projectile
  • ELVS for measuring deformation of specimens
  • 100,000 fps high speed video

Hydraulic Intermediate Strain Rate (HISR) Apparatus

The Hydraulic Intermediate Strain Rate (HISR) appparatus is used to perform uniaxial tension tests at strain rates ranging from 1.0-100s-¹. Sheet metal shear tests (continuous or interrupted) can also be conducted using this apparatus.

hydraulic intermediate strain rate apparatus

Specifications:

  • Stroke Rate: 15 000 mm/s
  • Stroke: 101.6mm (4”)
  • Hydraulic Actuator Capacity: 13.3kN (3,000lbf)
  • Load Cell: KISTLER 9500A4 ±30kN piezoelectric load cell
  • Extension: Enhanced Laser Displacement System (ELDS)
  • Data Acquisition: National Instruments 6212 USB, 250 000 samples/sec

IMATEK Instrumented Falling Weight Impact (Droptower)

Instrumented Falling Weight Impact (IFWI) testers can be used to perform experiments in compression, biaxial tension, toughness, and uniaxial tension, as well as, in low-cycle fatigue, through multiple impacts. In an IFWI experiment, regardless of the type, a striker (impactor) with some added mass is dropped onto either the specimen (compression, toughness, or biaxial tension) or a fixture which is attached to the specimen (uniaxial tension). At Waterloo, tension and compression testing at intermediate strain-rates (30-120 s-¹) are conducted using this apparatus.

IMATEK instrumented falling weight impact

Enhanced Laser Velocity System (ELVS)

The ELVS system, developed by UBC, is capable of measuring the displacement of an object over time. This system is comprised of a laser which generates a sheet of light, some lenses and a detector capable of measuring the intensity of the laser light. As an object passes through the beam of light, the intensity drops. A relation between light intensity and displacement can be determined experimentally. The ELVS can be used to measure such data as the deflection of composite panels impacted by a projectile. This data is particularly useful when characterizing personal protection systems such a body armour.

enhanced laser velocity system