This simulator runs a virtual tensile test on a dog-bone specimen held in wedge grips. It drives the specimen through a loading ramp and an unloading ramp while an extensometer tracks the gauge section, and it draws the stress-strain path as it forms.
• A 3D test machine, specimen and extensometer, with a live stress-strain trace that follows the loading and unloading path. • Five sliders: Young's modulus (50-220 GPa), yield stress (150-500 MPa), post-yield tangent (0-5 GPa), peak engineering strain (0.001-0.025) and original cross-section (20-100 mm2). • Six live readouts: engineering strain, engineering stress, tensile force, permanent strain, gauge extension and final residual extension. • Two presets: Elastic return (the specimen goes back to zero strain) and Permanent set (unloading to zero stress leaves a positive extension).
Yield strain is epsilon_y = sigma_y / E. Below it stress follows sigma = E epsilon; above it the bilinear law gives sigma = sigma_y + H (epsilon - epsilon_y), where H is the post-yield tangent. Unloading always follows a line with slope E, so the residual strain is epsilon_res = epsilon_peak - sigma_peak / E. The tensile force in kilonewtons is sigma (MPa) times area (mm2) divided by 1000.
The cycle is prescribed: 10 s of loading, 10 s of unloading and a 4 s observation hold. The material law is bilinear and monotonic with engineering stress and strain, so there is no necking, fracture, Bauschinger effect or hysteresis beyond permanent strain. Specimen extension is exaggerated in the drawing, while the metrics use the real 50 mm gauge length. Compare a peak strain below and above yield to see elastic return turn into permanent set.
Young's modulus, E. After yielding, unloading is elastic, so the stress falls along a line parallel to the original elastic loading line and the strain that is left at zero stress is the permanent set.
Stress is force per unit original area (MPa here) and strain is the extension divided by the original gauge length (dimensionless). Plotted against each other they describe the material rather than the specimen size.
If the peak strain stays below the yield strain sigma_y / E the specimen remains elastic and returns to zero. If it goes beyond, the plastic part of the strain is not recovered on unloading.
It uses a bilinear monotonic material law with engineering stress and strain. Necking, fracture, strain-rate effects, the Bauschinger effect and real machine compliance are not included.