Reliablity Assignment
Reliablity Assignment
Reliablity Assignment
2)
for the truss shown, the structural elements 1 and 7, 3 and 5, 2 and 6
have identical failure characteristics. Let the probability of failure be
P(1)=P(7)=0.02,
P(2)=P(6)=0.01,
P(3)=P(5)=0.02,
P(4)=0.03,
a) Calculate the reliability of the structure
b) Calculate the probability of failure.
E4 E2 E1 E3 E5
7) The failure rates of three components are 0.06 × 10-3, 0.18 × 10-3
and 0.92 × 10-6 per hrs. Find the failure rate, MTTP of the system
and reliability at 550 hrs if these components are connected in
parallel.
3]Write down the minimal tiesets and cutsets for the block diagram
shown
0.9
0.9
0.95 0.9
0.8
0.9
Fig(a)
0.8 0.9
Fig(b)
4]For the block diagram shown, write down the minimal tie sets and
minimal cutsets. From these obtain the reliability of the system,
assuming the elements to be independent. Also draw equivalent block
diagram obtained from tie sets and cut sets.
3]Write the procedure for MLE. What are the properties of MLE.
6]Data for the failure times of 309 radio transmitter receivers are given
in the following table
Instructions:
a] Question number 1 is compulsory.
b] Answer any four from the remaining six questions.
c] use of statistical tables and charts are permitted.
d] Assume suitable data if necessary.
Q1
a) Distinguish between reliability and quality of a product. (05)
b) List important properties of MLE. (05)
c) What is meant by tie set and cut set methods?
(05)
d) Three light bulbs are selected at random from 15 bulbs of which
five are defective. Find the probability that
(05)
i) none is defective
ii) at least one is defective.
Q2.
a) Explain with neat sketch failure pattern of component.
(10)
b) Explain method of decomposition for finding reliability of
system.
(10)
Q3.
a) The working life of machine component follows normal
distribution with standard deviation of 50 hour and mean 500
hour. If an organization uses 1000 of these components,
determine the expected number of components to be replaced
at or before 400 hour.
(10)
Q4.
a) Write down the minimal tiesets and cutsets for the block diagram
shown. Also find Reliability.
(10)
0.85
0.85
0.9 0.9
0.8
0.9