Frequency, dose and recovery

A material pilot with explicit limits

E02-F is an unregistered pilot, with no collected specimens or results. It is separate from the M03-D stiffening oscillator and the E01-S softening null. Conventional viscoelastic and Mullins-effect explanations remain rivals. Published Ecoflex experiments already report softening, recovery and thermal/rate effects.

Correct the readout before testing the mechanism

The primary observable is force–displacement tangent stiffness over a frozen strain interval, rate, preload and temperature. Define positive softening D = 1 − K/K₀. A secondary ringdown interpretation requires fixed effective mass, calibrated fixtures and a single underdamped mode.

fₙ = f𝒹 / √(1 − ζ²)
D = 1 − (fₙ/fₙ₀)²

A driven resonance peak is not automatically the undamped natural frequency. Damping, fixture compliance and slip can imitate a material change. A readout must also be shown not to erase or write the memory it measures.

Frequency, cycles and duration

The specified waveform is ε(t)=0.25−0.25 cos(2πft), from 0 to 50% engineering strain. Peak strain rate is 0.785/s at 0.5 Hz and 7.854/s at 5 Hz. Matched cycle count and matched duration comparisons answer different questions; none isolates every mechanism.

Acquisition and controls

Use synchronized force and specimen displacement with a pilot-validated bandwidth and phase delay; ≥1 ksample/s/channel is a proposed target. The HX711 datasheet gives 10 or 80 samples/s: only 2 or 16 samples per cycle at 5 Hz. Do not assume this yields accurate loop work.

Include duration-matched shams, heat-only histories, calibrated temperature/gradient monitoring and probe-only controls. Determine the cooldown from observed thermal stability. A 24-hour destructive sweep must not overwrite specimens intended for seven-day recovery. Validate removable fixtures or allow the actual fixture time.

Plan power from the pilot

Six specimens per arm is a pilot. For a proposed two-percentage-point practical margin, sample size changes sharply with the true contrast and variance. These normal-approximation examples target 90% power for the lower two-sided 95% interval to exceed that margin; they omit batch effects, small-sample correction, attrition and multiplicity.

Freeze one primary time and the absolute D(T2)−D(T1) contrast. Ratios are secondary and require a nonzero, identified denominator. A positive effect would distinguish only the tested material models under these controls.

Protocol and data templates

Complete pilot protocol · Stiffness and power calculations · Specimen template · Raw time-series template · Readout template

Calibration before a numerical claim

The SI extension of M03-D is now explicit, with synthetic parameters only. Frequency ratios are conditional on the writing regime, recovery, saturation and controlled displacement. E02-F remains a separate material pilot.

Physical units and ratio limits · Prospective evidence gates