|
|
《火工品可靠性评估方法》GJB376-87 当中大部分篇幅是数据表格。大约十年前,我用 VB 写了一个计算程序,不需要查表,在已知生产批量,抽样数量, 试验(检验)失效(失败)数,以及置信度这些条件后,用此程序可以瞬间算出该批产品的可靠度。
例1: 批量500, 抽25, 失效0, 置信度0.95时,该批产品的可靠度是 R=0.889808
例2: 批量500, 抽25, 失效0, 置信度0.85时,该批产品的可靠度是 R=0.928693
例3: 批量500, 抽50, 失效1, 置信度0.95时,该批产品的可靠度是 R=0.912149
以下是原程序——
' 成败型试验可靠度准确计算 计算依据:《火工品可靠性评估方法》GJB376-87
Private Sub Form_Click()
Open "批量500,抽50,失效1,置信度0.95.txt" For Output As 1 'R=0.912149
nn = 500 '批量
n = 50 '抽样数
F = 1 '失效数
D = 0.95 '置信度
R1 = 0: R2 = 1 '根在这个范围
pi = 3.1415926535: e = 2.718281828459
Dim h(50)
Dim B(50)
B(2) = 1 / 6: B(4) = -1 / 30: B(6) = 1 / 42: B(8) = -1 / 30: B(10) = 5 / 66
B(12) = -691 / 2730: B(14) = 7 / 6: B(16) = -3617 / 510: B(18) = 43867 / 798
B(20) = -174611 / 330: B(22) = 854513 / 138: B(24) = -236364091 / 2730
B(26) = 8553103 / 6: B(28) = -23749461029# / 870: B(30) = 8615841276005# / 14322
B(32) = -7709321041217# / 510: B(34) = 2577687858367# / 6
B(36) = -2.63152715530535E+19 / 1919190: B(38) = 2.92999391384156E+15 / 6
B(40) = -2.61082718496449E+20 / 13530: B(42) = 1.52009764391807E+21 / 1806
B(44) = -2.7833269579301E+22 / 690: B(46) = 5.96451111593912E+23 / 282
B(48) = -5.60940336899782E+27 / 46410: B(50) = 4.9505720524108E+26 / 66
GoTo 10
20: If y < 0 Then R1 = R: GoTo 10
If y > 0 Then R2 = R: GoTo 10
10: k = k + 1
R = (R1 + R2) / 2
If nn > 100 Then GoTo 40
x = nn * R: If x < 10 Then GoSub sub1: a1 = aaa 'a1 = (NR)!
x = nn * R: If x >= 10 Then GoSub sub2: a1 = aaa
x = nn * R - n: If x < 10 Then GoSub sub1: a2 = aaa 'a2 = (NR-n)!
x = nn * R - n: If x >= 10 Then GoSub sub2: a2 = aaa
a3 = 1 'a3 = (N)!/(N-n)!
For i = nn - n + 1 To nn
a3 = a3 * i
Next i
GoSub sub4
y = a1 / a2 / a3 * z - (1 - D)
GoTo 50
40: x = nn * R: GoSub sub3: L1 = LLL 'L1 = Log(NR)!
x = nn - n: GoSub sub3: L2 = LLL 'L2 = Log(N-n)!
x = nn: GoSub sub3: L3 = LLL 'L3 = Log(N)!
x = nn * R - n: GoSub sub3: L4 = LLL 'L4 = Log(NR-n)!
GoSub sub4
y = L1 + L2 - L3 - L4 + Log(z) - Log(1 - D)
50: If k / 2 = Int(k / 2) And k <= 50 Then
Print Tab(2); "k = "; k;: Print #1, Tab(2); "k = "; k;
If y >= 0 Then
Print Tab(12); "y="; Format(y, " ##0.000000000000000")
Print #1, Tab(12); "y="; Format(y, " ##0.000000000000000")
Else
Print Tab(12); "y="; Format(y, "###0.000000000000000")
Print #1, Tab(12); "y="; Format(y, "###0.000000000000000")
End If
End If
If k < 40 Then GoTo 20
If k >= 40 Then GoTo 30
30: Print: Print #1,
Print Tab(12); "R = "; Format(R, "0.000000")
Print #1, Tab(12); "R = "; Format(R, "0.000000")
Print Tab(12); "y = "; Format(y, "0.00000000000000")
Print #1, Tab(12); "y = "; Format(y, "0.00000000000000")
999: Close
Exit Sub
End
sub1: '广义阶乘子程序
nnn = 1000000
aaa = 1
For i = 1 To nnn
If x + i = 0 Then x = -i + 0.00001
aaa = aaa * i / (x + i)
Next i
aaa = aaa * nnn ^ x
Return
sub2: '用斯特林公式计算广义阶乘 x!
c1 = (1 + 1 / (12 * x) + 1 / (288 * x ^ 2))
c1 = c1 - 139 / (51840 * x ^ 3) - 571 / (2488320 * x ^ 4) + 163879 / (209018880 * x ^ 5)
aaa = Sqr(2 * pi * x) * (x / e) ^ x * c1
Return
sub3: '用斯特林公式计算广义阶乘的对数
If x <= 20 Then GoSub sub1: LLL = Log(aaa): Return
c1 = 0
For kv = 1 To 15 '25
c = B(2 * kv) / (2 * kv) / (2 * kv - 1) / (x ^ (2 * kv - 1))
c1 = c1 + c
Next kv
LLL = (x + 0.5) * Log(x) - x + Log(Sqr(2 * pi)) + c1
Return
sub4: '求系数 Z
h(0) = 1
For i = 1 To F
h(i) = h(i - 1) * (n - i + 1) * (nn - nn * R - i + 1) / i / (nn * R - n + i)
Next i
z = 0
For i = 0 To F
z = z + h(i)
Next i
Return
End Sub
|
|