Martindale Abrasion Weight Loss Extrapolator

The formula

This is the expression the tool evaluates. Every term is named underneath, with the unit it must be supplied in.

How the result is derived

Step by step, from the values you type to the figure on screen.

1. The 5 inputs are read from the form on every keystroke: Specimen Mass Before, Specimen Mass After, Cycles Run, Failure Threshold and Target Cycle Count.
2. Each value is checked against the accepted range in the input table below. A value outside its range stops the calculation rather than producing a misleading figure — the results blank out and a message appears.
3. The validated values are substituted into the expression above, which resolves Cycles to Failure Threshold together with every supporting figure in one pass — no value is carried over from a previous entry.
4. The supporting outputs — Mass Lost, Mass Loss, Loss Rate, Projected Loss at Target, Mass Loss Rate and Threshold Less Projected Loss — come from the same pass, so they always describe the same case as the headline figure.
5. Results are rounded for display only. The full-precision value is used throughout the chain, so reading a rounded intermediate figure back into the tool by hand can shift the last digit.

What each input means

Where to read each value on the floor, the unit it must be in, and the range the tool accepts.

What the tool returns

The headline figure and every supporting value it is built from.

Worked example

The tool loads with this case already solved — the Cycles to Failure Threshold shown above is its answer. Change one value and the difference from this baseline is the sensitivity of the result to that variable.

How to use it

1. Work through the input groups in order — Test Interval and Projection. The defaults are a realistic case, so you can change one value at a time and watch what moves.
2. There is no calculate button. Every figure recalculates as you type or drag, which is what makes this usable for a what-if sweep rather than a single answer.
3. Read Cycles to Failure Threshold in the dark results panel — that is the headline figure, expressed in no..
4. Check the supporting rows underneath (Mass Lost, Mass Loss, Loss Rate, Projected Loss at Target, Mass Loss Rate and Threshold Less Projected Loss) before acting on the headline — they are where an implausible input usually shows itself first.
5. Reset to defaults returns every field to the reference case, which is the quickest way to check whether a surprising result came from the tool or from an input you had changed earlier.

Where this is used

• Process planning — establishing Cycles to Failure Threshold before a trial is booked, so machine time and material in Testing, Standards & Metrology are committed against a calculated figure rather than an estimate.
• Costing and quotation — Cycles to Failure Threshold is an input to the cost sheet, and quoting from a worked number rather than a remembered one is what keeps a margin intact.
• Troubleshooting — when the floor result drifts from plan, entering the measured values (starting with Specimen Mass Before) shows how much of the gap in Cycles to Failure Threshold each variable explains.
• Teaching and study — the accepted ranges bracket normal Testing, Standards & Metrology practice, so moving one variable at a time shows the shape of the relationship rather than a single answer.

Assumptions and limits

• Linear extrapolation holds while abrasion stays in the steady phase. Fabrics with a pile, a coating or a surface finish lose the surface fast and then slow down, so a projection made from an early interval will be pessimistic — take the interval past the run-in.
• Every input is bounded to the range normal practice occupies (Specimen Mass Before 0.01 to 100 g, Specimen Mass After 0.001 to 100 g and Cycles Run 100 to 200000 no., and so on for the rest). Those bounds are guard rails against typing errors, not a claim that the formula fails one unit outside them.
• The calculation is deterministic: the same inputs always give the same result. It carries no allowance for machine condition, operator skill, ambient conditions or lot-to-lot material variation unless an input above explicitly represents one.
• Nothing is sent anywhere. The maths runs in your browser, so the numbers you type never leave the page.

Questions people ask