STH Stress Hypotheses Unit

The Stress Hypotheses Unit, "STH", allows the study and testing of stress hypotheses by applying loads in different directions on a test specimen point and measuring the deformations produced.

Normal and shear stresses are applied, avoiding transverse stresses. The test specimen is fixed to the unit on one side and weights are placed on the other side to create the stresses. A counterweight is used to compensate these weights.

These stress-creating weights are supported on a graduated plate placed on the specimen, which allows the weights to be fixed at 15° differences, adding also bending and torsional moments.

The test specimens have an annular cross-section in their loaded zone and the ends are reinforced for support.