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Graphic approximation technique |
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|  MIL-R-8236F
Graphic approximation technique. Based upon acceleration time plots from measurements or
computations; rise time, plateau duration, and G values may be obtained using the graphic approximation
technique shown in Figure 19. The procedures for establishing the accelerations and times are:
a.
Establish the calibration baseline.
b.
Establish the maximum (peak) acceleration magnitude.
c.
Construct a reference line parallel to the calibration baseline at a magnitude equal to 10
percent of the peak acceleration. The intersection of this line with the acceleration time
plot defines points 1 and 2.
d.
Construct a second reference line parallel to the calibration baseline at a magnitude
equal to 90 percent of the peak acceleration. The intersection of this line with the
acceleration time plot defines points 3 and 4.
e.
Construct the onset line defined by the straight line through points 1 and 3.
f.
Construct the offset line defined by the straight line through points 2 and 4.
Construct a line parallel to the calibration baseline, through the peak
g.
acceleration. The time interval defined by intersections of this line with the constructed
onset and offset lines (points 5 and 6) is the plateau (t).
h.
Locate the intersection of the constructed onset line with the calibration baseline (point
7). The time interval defined by points 7 and 5 is the rise time (tT).
For a given plot of accelerations, the specific G values are graphically obtained from the
i.
constructed onset and offset lines for the specific time at which the acceleration is the
greatest.
FIGURE 18. Graphic approximation technique
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