Downloaded from https://www.everyspec.com AMCP 706-198 Example No. 37 Several pieces of the same equipment are being tested in conjunction with a reli- ability-growth program. After 1200 total hours of testing time, there have been 8 failures. The individual failure times (not shown here) were used to calculate . 0.6 from Eq. 10-1. What is the current failure rate, and what it it estimated to be if there are 1800 more hours of testing? (Since j 1, the failure rate Is decreasing.) Prosedure Example 1. State the data (and calculated 1. T w 1200 hr results) which are given. * Ow 0.86 2. Find I(T) and A(T). Use Eqs. 2. I(T) - (0.6)(8)/1200-hr 10-3b and 10-4b. - 4.0/1000-hr a(T) .. (2/8)/2 - 0.5.
S. Find 4(T) and ^N(T). Use 3. 24(T) - 2(0.5) - 1.0 Eq. 10-5. 1,(T) - (4.0/1000-hr)e" 1.0 - 1.5/1000-hr Xv(T) - (4.0/1000-hr)'* 1.0 - 10.9/1000-hr. 4. Find t after 1840 more hours. 4. t - 1200 hr + 1800 hr a 3000 hr. 8. Find A t), 5(t), 0(t). Use 5. tIT - 3000 hr/1200 hr- 2.5 Eqs. 10-2, 10-3a, 10-4a. .(t) - 8(2.5)0.6 = 13.88. (t)- (4.0/1000-hr)(2.5)'11 "1 - 2.77/1000-hr 0(t) - 0.5{[1 + (1 + 0.61n2.5)31/2}u| - 0.682. 6. Find X &(t), •u(O). Use Eq. 8. 29(t) - 2 x 0.852 a 1.30 10-5. Calculate the ratio of 4(t)- (2.77/i000-hr)" t xv~w)•, u). -0.75/1000-hr (t) - (2.77/1000-hr)e# - 10.2/1000-hr.