Abstract
The stress measurement method using the fractal analysis of grown grains which occur in an electrodeposited copper foil was examined in this report. The electrodeposited copper foil was adhered to the titanium specimen and cyclic loading test was carried out under bending or torsion condition. Fractal property was observed in the microphotograph of grown grains which occurred by various repeated loading conditions and it became clear that the fractal dimension calculated by the box-counting method depends on the maximum shear stress and a number of cycles. The expression among maximum shearing stress, number of cycles and fractal dimension was proposed based on the experimental results. The combination of this expression and the traditional formula related to the grown grain density enables us to estimate the maximum shearing stress even if the number of cycles is unknown. Moreover, a unique relation was recognized between the grown grain density and the fractal dimension. This means that the fractal dimension can be estimated from the grown grain density. This result suggests that the maximum shearing stress can be obtained only by measuring the grown grain density.
