The analysis of joint allowable load data for the case where data are required for procuring or regulatory agency (not for use in MIL-HDBK-5) for a limited range of sheet thickness and fastener diameter is as follows. An analysis similar to that described in Section 9.7.1.4 is required for data over the limited t/D range evaluated. In the special case where one sheet thickness and one fastener diameter have been tested in accordance with the requirements of Section 9.7.1.3, data will be analyzed as follows: the ultimate-load calculations will be made utilizing the statistical formulas listed in Section 9.7.1.3, where the k value is obtained from Table 9.10.1 for the appropriate number of test values (n) and 90 percent probability (B) value at a 95% confidence level. These ultimate-load values will be compared with values computed from bearing ultimate strengths of the joint material. In each comparison, the lower of either (1) statistical value computed from joint test data, (2) computed B-basis ultimate value from regression analysis, (3) computed bearing ultimate strength, or (4) fastener shear ultimate strength, will be the ultimate-load design allowable.
Similarly, the yield-load values will be compared with values computed from bearing yield strengths of the joint material. These yield-load values will be compared with values computed from bearing yield strengths of the joint material. In each comparison, the lower of either (1) statistical value computed from joint test data, (2) computed B-basis yield value from regression analysis, (3) computed bearing yield strength, or (4) fastener shear yield strength, will be the yield-load design allowable.
The load values so calculated will be rounded to three or four significant figures as follows:
- (1) Load values less than 1000 will be rounded to 3 figures (load values less than 100, 2 figures).
- (2) Load values greater than 1000 will be rounded to 4 figures. The fourth figure will be a 0 or 5.