Stress Relaxation Test Dataset of Cylindrical PVA Gel Polymer Electrolyte (GPE) Samples

This dataset accompanies the research on the nonlinear mechanical characterization of Poly(vinyl alcohol) (PVA) gel polymer electrolytes (GPEs) for structural supercapacitors (SSCs). It contains the raw experimental data acquired during displacement-controlled compression stress-relaxation tests performed on cylindrical freeze–thaw PVA hydrogel samples. The measurements were conducted using a universal testing machine (Zwick Roell Z010) under a predefined loading protocol consisting of an initial preload, a constant-rate compression phase, and a subsequent stress-relaxation holding period. Each specimen was subjected to three consecutive loading cycles to investigate the repeatability and time-dependent mechanical response of the material. The dataset includes the time, force, and crosshead displacement signals for each test. These data provide the basis for determining stress-relaxation behaviour and serve as input for constitutive model development and validation. The dataset enables independent analysis of the viscoelastic response of PVA gel polymer electrolytes and supports the development and validation of constitutive models for hydrogel electrolytes used in structural energy-storage applications.