Plastic film · Laboratory data reduction
Plastic Film Dart Impact Failure Weight Calculator
Check five-level successive-group dart-impact arithmetic for the estimated plastic-film mass at 50% failure.
Formula and method
Highest level WL = lowest level + 4 × increment. Sum S = failure percentages at all five levels. Estimated failure mass WF = WL − increment × (S ÷ 100 − 0.5).
Inputs and units
Enter the lowest missile mass, uniform mass increment, equal specimens per level, and failures at five ascending mass levels. This screen requires zero failures at level 1, all failures at level 5, whole-number counts, and nondecreasing failures.
Worked example
Five groups of 10 specimens at 100, 120, 140, 160, and 180 g with 0, 2, 5, 8, and 10 failures give 140 g estimated 50% failure mass.
When to use it
Use to verify arithmetic for a completed alternative successive-group series when the laboratory method or specification calls for this design.
How to interpret the result
The result estimates the missile mass producing 50% failure on the entered method and conditioning basis. Keep dart geometry, drop configuration, specimen thickness, failure definition, conditioning, and group data.
Assumptions and limitations
This is not the staircase calculation and does not design an efficient test series, supply a confidence interval, replace method-specific rounding, or approve compliance. Five levels are intentionally fixed for an auditable screen.
Validation guidance
Confirm equal group sizes and increments, verify the bounding zero- and 100%-failure groups, check every specimen disposition, reproduce the sum of percentages, and apply the current laboratory procedure for final reporting.
FAQ
Can I use staircase up-and-down observations here?
No. Staircase data use a different sequence and reduction. This calculator is explicitly limited to five equal successive groups.
Sources
ASTM D1709: Impact Resistance of Plastic Film by the Free-Falling Dart Method