Fiber Tensile Testing

Tensile Testing Experiments — down to the µN-Range

Fiber tensile module with clamps for foils and heating.The outer dimensions of the Fiber Tensile Module are 80 x 100 x 22 mm3, it is mounted to the SEM or light microscope specimen stage "like a large specimen". It allows in-situ observation of tensile testing experiments at extremely low forces, yet very high load resolution (down to 1×10-5 N). The tensile speed range is 0,1 to 20 µm/s. These features, coupled with maximum stiffness of this substage, allow very accurate measurements on fibers of down to 2.5 µm diameter, and several millimeters length. The specimens can be observed statically or dynamically at magnifications well beyond 10 000 x in daily routine work.
The load is measured by the principle of frequency variations on a spring-loaded metal wire. The displacement is taken by a differential transformer (LVDT).
Fiber Clamps with wire heating
The enlarged view shows the specimen holder, which is a pair of ceramic tubes, ground down to half their diameter (red tips). One side is attached to a parallel sled, driven by a combination of DC-tacho-motor/angular encoder for precise recognition of the displacement. A fine tungsten wire touches the specimen from underneath at 90 degrees. This wire allows heating up the specimen locally.
 
Crack Growth on a T300 Carbon Fiber Precursor During Slow Increase of the Tensile Force Crack Growth on a T300 Carbon Fiber Precursor During Slow Increase of the Tensile Force
Pic.3: Crack Growth on a T300 Carbon Fiber Precursor During Slow Increase of the Tensile Force
Fracture Surfaces on Mono Fibers Fracture Surfaces on Mono Fibers
Pic.4: Fracture Surfaces on Mono Fibers

Fiber tensile module overall

Pic.1: Fiber Tensile Module, Overall View

Specimen area with heating

Pic.2: Specimen Clamping and Heating for Foils

Clamp for foils detail

Clamp Detail

Dortmund Skyline