Plastics — Determination of modulus of elasticity by alternating flexure

In this manner, small amplitudes of the deflection oscillation can thus result in large amplitudes of the torsion oscillation at the appropriate frequency.

A deflection member (14, 14') is provided between at least one torsion member (12, 12') and the support (13).

Said deflection member undergoes a deflection oscillation which induces a torsion oscillation of the mirror surface (11) about the torsion axis (19).

Reinforcing threads produced according to the inventive method are characterised by an intimate impregnation with polymers and thus by high stability under load and fatigue strength under reversed bending stresses.

Such finishes significantly enhance the flex life of woven glass fabrics (10) by improving the acid and alkali corrosion resistance of the fibers.

Said maraging steel typically exhibits tensile strength Rm of about 2800 Mpa's, yield strength Rp0.2 of about 2600 Mpa's, Vickers hardness > 800 and alternating flexure strength 0bw of about 1550 Mpa's.

ISO 6266:2013 specifies a method for the determination of the fatigue indexes of alpine skis (i.e. the resistance of the skis to changes in shape and of stiffness) after a bending test with cyclic loading.

The high-modulus mixes according to the invention have a modulus of rigidity E*, measured at 15°C and at 10 Hz, of greater than 15 × 103 MPa and a reversed bending fatigue strength ε6, at 10°C and at 25 Hz, of greater than 140 × 10-6.

ISO 7798:2017 specifies a method for the determination of the fatigue indexes of cross-country skis (i.e. the resistance of the skis to changes of bottom camber height or irreversible damage) after a bending test with cyclic loading.