A diagnosis unit is used to determine certain select material parameters of a wire (elongation limit, modulus of elasticity, modulus of hardening, Bauschinger modulus, etc.) which are needed for the virtual description of a wire straightening process using a simulation program.
Finite, unidimensional curved wire sections are subjected for this purpose to a bending load, whereby the number, magnitude and direction of bends applied to the wire varies. The wire curvatures and the corresponding bending moments and torques for discrete values of the bending angle are derived either directly or from intermediate values during the bending tests. Plotting the bending moments as a function of the curvatures in a graph produces a bending moment / curvature curve. The characteristic values of such a curve can be used to calculate the material parameters.
See Also
Adapted from “"We do it straight" — Wire Straightening”, p. 69 (ISBN 3-00-005897-4).