Research note / Cycle 007
The zero after unloading
A restart study for the proposed strip bench separates a zeroed display from the displacement retained in its raw record.
A strip must come back from a load
The Space Elevator program proposes a bench that would pull a 100 mm surrogate strip while keeping gauge extension, frame travel and grip movement separate. Before any strength claim, the displacement channel must show what remains after unloading. The bidirectional acceptance study established the need for return readings; this study asks what survives when the operator re-zeros the display.
The seven software cases use three authored positions: initial, loaded and returned. The clean gauge trace is 0, 200, 0 micrometres. A stationary comparison channel remains at zero. The model subtracts the reference change from the gauge change between the first and last samples, then compares the residual with the existing 6 micrometre calibration allowance. This is a proposed return check, not an installed instrument calibration.
Tare does not unload the specimen
A second trace ends at 12 micrometres. Setting the display to zero leaves that raw difference unchanged, so both the untouched and tared versions are held. If the initial raw reading has been discarded, the model cannot reconstruct the return and reports an unavailable result. It does not substitute the displayed zero.
When both gauge and stationary reference shift by 12 micrometres, subtraction gives zero. That can account for an authored common sensor shift. A hidden-coupling case supplies exactly the same numbers, but the reference has moved with the simulated specimen. The reviewer cannot distinguish the two histories and gives the same favorable conditional result. A reference name is insufficient evidence of stationary behavior.
A completed procedure, an unperformed run
Reed has completed the requested acceptance sequence as a reviewable bench procedure: preserve the initial raw readings, retain every tare, observe the unloaded return, and stop if reference coverage is absent. Voss has incorporated that sequence into the equipment evidence request. No frame, displacement sensor or independent reference custodian has been secured.
An observed residual would still require separate checks for grip movement, thermal drift, sensor behavior and specimen change. These fixtures identify no material damage. The procedure cannot authorize force or strength measurements, and the earlier full-range and mounting obligations remain.
Results at a glance
| Case | Corrected return (um) | Decision |
|---|---|---|
| clean_return | 0 | within_model_return_allowance |
| common_sensor_shift | 0 | within_model_return_allowance |
| residual_extension | 12 | hold_return_offset |
| tare_with_raw | 12 | hold_return_offset |
| tare_without_raw | Unavailable | hold_missing_raw |
| reference_outage | Unavailable | hold_reference |
| hidden_coupled_reference | 0 | within_model_return_allowance |