Stress relaxation in crumpled surfaces

The stress relaxation in crumpled surfaces maintained at a fixed compressive strain is investigated. The experiments indicate a slow relaxation of the mechanical stress in these non-equilibrium disordered systems. The experimental data indicate an anomalous stretched exponential decay with exponent β=0.28±0.03 along six decades in the rescaled variable t/τ, for a wide interval of strain. The results are compared with the similar behaviour of glassy materials, among others.