The Hopkinson Bar test setup provides our customers the opportunity to evaluate stress-strain behavior under high strain rates on elastomeric materials.

Objective
Equipment Specifications
Applications
Theory
Products Tested

 

Objective
ARDL's Engineering department uses the Split Hopkinson Pressure Bar (SHPB) test setup to perform stress-strain testing on materials at high strain rates for large strain amplitudes. When very large strains and strain rates are expected in a given application, the conventional experimental techniques are inadequate due to experimental error caused by the “Inertia Effect” of the test crosshead.

Equipment Specifications
     • Strain Rate Range of 10² to 10⁶s^-1
     • Temperature -40°C to 200°C
     • Bulk and Uniaxial Tests on Thin Specimens
     • High-Speed Digital Data Acquisition Using Customized Software to Accommodate the
       Propagation of Stress Waves in the Elastomer Samples
     • High-Speed 4-Channel Tektronix Digitizers

Applications
Impact Energy Absorption
     • Energy Absorbing Materials, Structures and Devices for Vehicles

Projectile Arrest
     • Containment and Electrical/Electronic Packaging
     • Cellular Materials (Wood, Foam, Honeycomb) and Structures

High Rate Material Properties
     • Shock Waves in Solids
     • Impact on Ceramics, Fiber-Reinforced Composite Shells, Sandwich Panels, Polymers
       and Elastomers and Reinforced Structures

Dynamic Structural Response
     • Dynamic Structural Plasticity
     • Fragmentation, Penetration and Perforation of Plates and Shells

Theory
The Split Hopkinson Pressure Bar technique measures the dynamic stress strain response by introducing a stress wave in the test sample.

V₁ and V₂ are the velocities at the incident bar/specimen and specimen/output bar interfaces, respectively.

L is the length of the specimen, C₀ is the longitudinal sound velocity in the pressure bar.
Using the above equation the stress-strain behavior is determined.

High strain rate material properties are crucial for geometric optimization using FEA.

Product design will be performed using the high strain rate material data from Hopkinson Bar and the final design verification will be done by ARDL Instrumented Impact Testing.

Products Tested
     • Actuator Components
     • Aerospace Applications
     • Airbag Impact
     • Automotive Brakes
     • Bulletproof Vests
     • Car Bumpers
     • Crash Analysis
     • Dummy Testing
     • Gaskets & Washers
     • Gas Tanks
     • Helmets
     • Industrial Conveyors
     • Packaging Materials
     • Polymer Projectiles
     • Power Tool Components
     • Printing Rollers
     • Tires
     • And Many More!