Question 1

Consider a product with three components in series,with reliabilities of 0.90,0.80,and 0.99 for components A,B,and C,respectively.Furthermore,component B uses a backup that also has a reliability of 0.80.What is the reliability of the system?

Accepted Answer

The reliability of the system can be found using the formula:

R(system) = R(A) * R(B) * R(C)

However, since B has a backup with a reliability of 0.80, the reliability of B can be represented as:

R(B) = 0.8 + 0.2 * (1-0.8) = 0.96

This means that the overall reliability of the system can be calculated as:

R(system) = 0.90 * 0.96 * 0.99 = 0.85536

Therefore, the reliability of the system is 0.85536 or approximately 0.86. The answer is D, 0.85536.

Question 2

While breakdowns occur randomly,their frequency is somewhat predictable through such tools as the product failure rate,MTBF,and the breakdown costs model.

Accepted Answer

The statement is true. While breakdowns may occur randomly, their frequency can be estimated using different tools such as product failure rate, Mean Time Between Failures (MTBF), and breakdown cost models.

Question 3

A job consists of a series of three tasks.Task 1 is performed correctly 98% of the time,task 2 is performed correctly 99% of the time,and task 3 is performed correctly 97% of the time.The reliability of this job is

Accepted Answer

We can use the formula for calculating reliability of a series system: R = R1 x R2 x R3, where R1 is the reliability of task 1, R2 is the reliability of task 2, and R3 is the reliability of task 3.

R = 0.98 x 0.99 x 0.97
R = 0.9411

So the reliability of this job is 94.11%, which means that it can be expected to be performed correctly 94.11% of the time. Therefore, the best choice is B.

Question 4

A system has three components in parallel with reliabilities 0.9,0.7,and 0.5.System reliability is

Accepted Answer

The system reliability in parallel is given by the multiplication of the reliability of the individual components. 
Therefore, the system reliability is: 
0.9 x 0.7 x 0.5 = 0.315 
Thus, the correct option is D) 0.985.

Question 5

Which of the following best illustrates the importance of employee involvement in achieving successful maintenance and reliability?

Accepted Answer

Choice D describes how employee involvement, through reward systems and power sharing, combined with good maintenance and reliability procedures, can lead to improved capacity and reduced variability. This highlights the importance of involving employees in achieving successful maintenance and reliability, as their input and collaboration can contribute to better outcomes. The other choices do not directly address the importance of employee involvement in achieving successful maintenance and reliability.

Question 6

An optimal maintenance policy strikes a balance between the costs of breakdown and preventive maintenance so that the total cost of maintenance is at a minimum.

Accepted Answer

An optimal maintenance policy is designed to minimize the total cost of maintenance, which involves balancing the costs associated with breakdown maintenance and preventive maintenance. By finding the optimal maintenance frequency and selecting the most effective maintenance methods, an organization can reduce the overall costs of maintenance while maximizing the reliability and availability of its assets.

Question 7

A product has three components,A,B,and C,with reliabilities of 0.95,0.98,and 0.995.Engineers intend to put a redundant component A that has reliability 0.70.With this change,system reliability will

Accepted Answer

To find the new reliability, we need to use the formula for parallel components:
R_total = 1 - (1 - R_A)(1 - R_B)(1 - R_C)
where R_total is the reliability of the system with the redundant component A and R_A, R_B, and R_C are the reliabilities of components A (redundant), B, and C, respectively.

Substituting the given values, we get:
R_total = 1 - (1 - 0.70)(1 - 0.98)(1 - 0.995)
R_total = 0.99916

Therefore, the system reliability will rise to 0.99916, which is higher than the original reliability of 0.95. Therefore, the answer is C) rise.

Question 8

Which of the following statements about maintenance at the Pickering Nuclear Station is false?

Accepted Answer

The statement that maintenance at the Pickering Nuclear Station does not provide the province of Ontario with any significant amount of electricity supply is false. The station contributes significantly to Ontario's electricity supply.

Question 9

What is the reliability of a four-component product,with components in series,and component reliabilities of .90,.95,.98,and .99?

Accepted Answer

The answer of What is the reliability of a four-component...

Question 10

Components A,B,and C are connected in series.Component D is connected in parallel to component B.Which of the following statements is true?

Accepted Answer

Since components A, B, and C are connected in series, all three must work for the system to work. However, since component D is connected in parallel to component B, either component B or component D can work for the system to work. Therefore, the system works when A works, C works, and either B or D works, making choice C the correct answer. Choice A is incorrect because only one of B or D needs to work, not both. Choice B is incorrect because component D can still work even if component B doesn't work. Choice D is incorrect because components B and C are not backups to A. Choice E is incorrect because all three components A, B, and C need to work for the system to work.

Question 11

TPM (total productive maintenance)is an application of TQM (total quality management)principles to the area of maintenance.

Accepted Answer

TPM is indeed an application of TQM principles to the area of maintenance.

Question 12

What is the reliability of the three components connected in series shown below?

Accepted Answer

The answer of What is the reliability of the three...

Question 13

A system is composed of three components A,B,and C.All three must function for the system to function.There are currently no backups in place.The system has a reliability of 0.966.If a backup is installed for component A,the new system reliability will be

Accepted Answer

If a backup for component A is installed, the system will be able to function even if component A fails, increasing the overall reliability of the system. Therefore, the new system reliability will be greater than the original reliability of 0.966.

Question 14

The probability that a product will function properly for a specified time under stated conditions is

Accepted Answer

The probability that a product will function properly for a specified time under stated conditions is known as reliability.

Question 15

The objective of maintenance and reliability is to

Accepted Answer

The objective of maintenance and reliability is to maintain the capability of the system, which means ensuring that the system is able to operate at the required level of performance and productivity. This involves a combination of preventive, predictive, and corrective maintenance activities, as well as continuous improvement efforts to optimize the design, operation, and maintenance of the system over its lifecycle. The other options are not the primary objectives of maintenance and reliability.

Question 16

The objective of maintenance and reliability is to maintain the capability of the system.

Accepted Answer

The objective of maintenance and reliability is to ensure that the system remains capable of performing its intended function. This includes minimizing downtime, reducing the frequency and impact of failures, and optimizing the use of resources. Ultimately, the goal is to maximize the availability, performance, and safety of the system in order to meet business objectives and customer needs.

Question 17

A system has three components in series with reliabilities 0.9,0.7,and 0.5.System reliability is

Accepted Answer

The system reliability in series is the product of individual component reliabilities. Thus, the system reliability is 0.9*0.7*0.5=0.315.

Question 18

As the number of components in a system connected in a series decreases,all other things being equal,the reliability of the system usually

Accepted Answer

When components are connected in a series, the failure of any one component can cause the whole system to fail. Therefore, as the number of components in a series decreases, the likelihood of a failure decreases, increasing the reliability of the system.

Question 19

Simulation models and expert systems are useful tools for enhancing maintenance.

Accepted Answer

Simulation models and expert systems can be used to analyze maintenance data, predict failures, and recommend maintenance actions. They can also help to optimize maintenance schedules and reduce downtime. Therefore, they are useful tools for enhancing maintenance.

Question 20

Which of the following is a reliability tactic?

Accepted Answer

Reliability tactics aim to improve the overall reliability of a system or process. Improving individual components (A) can increase overall reliability, as can providing redundancy (C), which involves having backup components or systems in case of failure. Increasing repair speed (B) does not address the underlying reliability of the system and is not considered a true reliability tactic. Therefore, the best choice is D, as both improving individual components and providing redundancy are effective reliability tactics.

Quiz 17: Maintenance and Reliability