Document ID: chunk:federal_register_of_legislation:F2005L03990:reg:60:p2
Version: federal_register_of_legislation:F2005L03990
Segment Type: reg
Provision Reference: reg 60 (pt 2/9)
Character Range: 72618–75111

Figure 2 for an illustration of how to locate these sections within the honeycomb block. Each of these larger samples shall be cut into samples for certification testing (150 mm x 150 mm x 50 mm).Certification shall be based on the testing of two samples from each of these four locations. The other two should be made available to the applicant, upon request.
2.2.  Sample size
 Samples of the following size shall be used for testing:
 Length: 150 mm  6 mm
 Width: 150 mm  6 mm
 Thickness: 50 mm  2 mm
 The walls of incomplete cells around the edge of the sample shall be trimmed as follows:
 In the "W" direction, the fringes shall be no greater than 1.8 mm (see Figure 3).
 In the "L" direction, half the length of one bonded cell wall (in the ribbon direction) shall be left at either end of the specimen (see Figure 3).
2.3.  Area measurement
 The length of the sample shall be measured in three locations,12.7 mm from each end and in the middle, and recorded as L1, L2 and L3 (Figure 3). In the same manner, the width shall be measured and recorded as W1, W2 and W3 (Figure 3). These measurements shall betaken on the centreline of the thickness. The crush area shall then be calculated as:
2.4.  Crush rate and distance
 The sample shall be crushed at a rate of not less than 5.1 mm/min and not more than 7.6 mm/min. The minimum crush distance shall be 16.5 mm.
2.5.  Data collection
 Force versus deflection data are to be collected in either analog or digital form for each sample tested. If analog data are collected then a means of converting this to digital shall be available. All digital data shall be collected at a rate of not less than 5 Hz (5 points per second).
2.6.  Crush strength determination
 Ignore all data prior to 6.4 mm of crush and after 16.5 mm of crush. Divide the remaining data into three sections or displacement intervals (n = 1, 2, 3) (see Figure 4) as follows:
  (1) 06.4 mm - 09.7 mm inclusive,
 (2) 09.7 mm - 13.2 mm exclusive,
 (3) 13.2 mm - 16.5 mm inclusive.
 Find the average for each section as follows:
 where m represents the number of data points measured in each of the three intervals. Calculate the crush strength of each section as follows:
2.7.  Sample crush strength specification
 For a honeycomb sample to pass this certification, the following conditions shall be met:
 0.308 MPa  S(n)  0.342 MPa for 0.342 MPa material
 1.540 MPa  S(n)  1.711 MPa for 1.711 MPa material
 n = 1, 2, 3.
2.8.  Block crush strength specification
 Eight