Pendulum Energy
Falling-pendulum testing devices calculate the energy consumed when a ballistic tearing force propagates an initial cut through woven or nonwoven textiles. The elmendorf tear test utilizes a weighted pendulum raised to a fixed starting position and released to tear a notched fabric sample. Scale pointer readings convert potential energy loss into force units expressed in grams or newtons.
Fabric buyers require minimum tear values to verify structural durability under sudden stress conditions.
Tear Resistance
Yarn mobility within the weave structure governs how individual ends group together to resist tear propagation. Smooth filament yarns slip easily to form protective bundles, yielding higher tear values than tightly bound spun yarns.
Specimen Slit
Standardized testing requires cutting an accurate starting slit in rectangular specimens prepared in both warp and weft directions. Finishes like resin crosslinking or flame retardants reduce yarn mobility, lowering measured tear strength compared to untreated fabric webs. Technicians calibrate pendulum capacities using interchangeable augment weights to keep test readings within twenty to eighty percent of full scale.
Force Boundary
Extremely extensible knits or elastomeric fabrics flex rather than tear, rendering ballistic pendulum measurements invalid. High-density industrial fabrics exceeding pendulum capacity require trouser tear or trapezoidal test protocols.
