US 4,198,870 A · Constant point of load application fracture specimen loading machine

Abstract

A constant point of load application fracture specimen loading machine for applying a load between grips that engage opposite grip groove faces of a slotted specimen that preferably has as a remainder portion in that slot a "V" shaped slot root whereby, when the machine grips are moved apart, they rotate so as to apply a constant point of load application to pull the specimen apart at that slot root. The machine of the present invention is useful for measuring the fracture toughness, fatigue-crack growth resistance, or stress corrosion crack growth resistance of slotted specimens providing a unique force application system whereby sliding friction losses are minimized, and other introduced effects, such as from specimen grip machining tolerances, or the like, are largely automatically compensated for.

Claims20

Dependent claims

A constant point of load application fracture specimen loading machine consisting of,

a plurality of lever arms;
means for pivotally connecting together said lever arms;
a pair of grips each secured to a lever arm below said pivot means, which grips, when said lever arms are pivoted together, fit within grip grooves of a test specimen, which grips, when said lever arms are pivoted apart, are moved therewithin in an arc that approximates an arc of travel that is made by segments of said test specimen as it splits apart;
means for pivoting apart said lever arms;
and
means for measuring the load applied to said test specimen through the lever arms.

3 more elements

Dependencies are inferred from the claim text.

Constant point of load application fracture specimen loading machine

Life of this patent

Constant point of load application fracture specimen loading machine

Life of this patent

Abstract

Claims20