Download RELIABILITY ENGINEERING AND RISK ANALYSIS A PRACTICAL GUIDE 3RD EDITION MODARRES SOLUTIONS and more Exams Engineering Economy in PDF only on Docsity!
RELIABILITY ENGINEERING AND RISK
ANALYSIS A PRACTICAL GUIDE 3RD
EDITION MODARRES SOLUTIONS MANUAL
COMPREHENSIVE EXAM SCRIPT 2026
SOLVED QUESTIONS GRADED A+
⩥ TOP EVENT. Answer: The failure event of a particular system under study. ⩥ BASIC EVENT. Answer: An event which cannot be subdivided further and is the terminating point of the branch of the tree. ⩥ Fault. Answer: An abnormal undesirable state of a system attributed to wrong command implementation, no command implementation, or failure of a system/component. ⩥ Failure. Answer: Loss of functioning of the system or any component of the system. ⩥ Primary Failure. Answer: Failure that occurs due to the system itself, such as leakage or failure within the lifespan, with no exposure to the surroundings.
⩥ Secondary Failure. Answer: Failure that occurs due to exposure of the system to the surroundings or manufacturing errors. ⩥ MOE. Answer: A Multiple Occurring Event or failure event mode that occurs more than one place in the Fault Tree. ⩥ Boolean Logic. Answer: A system of algebraic notation used in FTA to divide each step into two outcomes: True or False. ⩥ AND Relationship. Answer: A parallel relationship in FTA where all conditions must be true for the event to occur. ⩥ OR Relationship. Answer: A series relationship in FTA where at least one condition must be true for the event to occur. ⩥ Hierarchical Representation. Answer: A structured diagram in FTA showing the dependencies among various events. ⩥ Preventive Analysis. Answer: An analysis performed to protect the end user from unidentified and unacceptable consequences. ⩥ Failure Mode and Effects Analysis (FMEA). Answer: A risk technique that can be supplemented by Fault Tree Analysis.
⩥ Pressure Vessel Burst. Answer: An example of failure where the pressure vessel fails. ⩥ MOB. Answer: Multiple Occurring Branch is a branch that is used in more than one place in FT (All basic events in MOB will be MOE's) ⩥ Branch. Answer: A sub section of tree ⩥ Module. Answer: An independent subtree or branch that contains no outside MOE or MOB and is not a MOB ⩥ Cut Set (CS). Answer: A set of events starting from basic event to the undesirable top event that together cause the top event to occur is called Cut Set ⩥ Min CS (MCS). Answer: A CS with minimum number of events that can still cause the top event ⩥ Super Set. Answer: A CS that contains a MCS plus additional events to cause the top undesirable event. ⩥ Critical Path. Answer: The highest probability CS that drives the top undesired event probability
⩥ Cut Set Order. Answer: The number of elements in a CS ⩥ Cut Set Truncation. Answer: Removal of cut sets from consideration during the FT evaluation process. CS's are truncated when they exceed a specified order and/or probability. ⩥ Boeing's Use of FTA. Answer: Later adopted and extensively applied by the Boeing Company as system safety analysis tool (1963) and applied to entire Minuteman system for safety (1964-67, 1968-99) ⩥ First Technical Paper. Answer: First technical paper presented at the first system safety conference, held in Seattle, June 1965 ⩥ Commercial Aircraft Design. Answer: Use by Boeing for the design and evaluation of commercial aircraft, (1966) ⩥ FTA Simulation Program. Answer: Boeing developed 12-phase FTA simulation program on a Colcomp roll plotter ⩥ Nuclear Power Industry Adoption. Answer: Further adopted by Nuclear Power industries (1971-80)
⩥ FTA in Operation Phase. Answer: FTA including operator and procedure characteristics can be used to study an operating plant to identify potential combinations of failures, for specific accidents ⩥ Type of Results. Answer: A listing of sets of equipment and/or operator failures that can result in a specific accident. These sets can be qualitatively ranked by importance ⩥ Nature of Results. Answer: Qualitative, with quantitative potential. The fault tree can be evaluated quantitatively when probabilistic data are available ⩥ Staff Requirements. Answer: One analyst should be responsible for a single fault tree, with frequent consultation with the engineers, operators, and other personnel who have experience with the systems/equipment that are included in the analysis ⩥ Team Approach. Answer: A team approach is desirable if multiple fault trees are needed, with each team member concentrating on one individual fault tree. ⩥ Data Requirements. Answer: A complete understanding of how the plant/system functions and knowledge of the plant/system equipment failure modes and their effects on the plant/system
⩥ Time and Cost Requirements. Answer: Highly dependent on the complexity of systems involved. ⩥ Fault Tree Analysis. Answer: A systematic method for analyzing the causes of system failures. ⩥ Gate Event. Answer: A logic operator that combines input nodes to determine the output event. ⩥ Conditional Event. Answer: An event that must occur for a gate event to happen. ⩥ Transfer Event. Answer: A pointer to a subtree branch used elsewhere in the fault tree. ⩥ AND Gate. Answer: A gate that requires all input events to occur for the output to occur. ⩥ OR Gate. Answer: A gate that requires at least one input event to occur for the output to occur. ⩥ NOT Gate. Answer: A gate that outputs the opposite of the input event.
⩥ Regulatory Impact. Answer: The implications of the top event in relation to laws and regulations. ⩥ Normal Event. Answer: An event that describes a normally expected system state. ⩥ Dormant Event. Answer: An event that is not currently active but may become active. ⩥ Union. Answer: A logical operation where at least one of the events must occur. ⩥ Intersection. Answer: A logical operation where all specified events must occur. ⩥ Immediate Event. Answer: Collection of past events and previous experiences that should always be included in FTA. ⩥ Necessary Event. Answer: Events that are actually necessary for the analysis; inclusion of small faults leads to complicated visualization. ⩥ Sufficient Event. Answer: Events that do not exceed the minimum necessary for the analysis.
⩥ Support Information. Answer: Information such as list of components, boundary diagram, schematic, code requirements, engineering noises, examples of similar products, and previous FTA data. ⩥ Potential Causes of Hazard. Answer: Causes listed starting from the top event, focusing on completion of a single level before proceeding to the next. ⩥ Team Work Process. Answer: The collaborative effort required to develop relationships of causes to a failure or fault. ⩥ Primary Fault. Answer: A type of causing event identified in the fault tree analysis. ⩥ Secondary Fault. Answer: A type of causing event identified in the fault tree analysis. ⩥ Command Fault. Answer: A type of causing event identified in the fault tree analysis. ⩥ Probability Estimation. Answer: The process of estimating the likelihood of causes at the base-level event. ⩥ Fault Tree Construction. Answer: The process of connecting events to AND gates and OR gates to analyze the system.
⩥ Higher reliability component. Answer: A component selected to replace a base-level event component, often at a higher cost if not identified early in product development. ⩥ Physical Redundancy. Answer: The use of a redundant component placed in parallel to another, requiring both to fail simultaneously for a hazard to occur. ⩥ Software Redundancy. Answer: The addition of a sensing circuit to change the state of the product, reducing event severity by protecting components. ⩥ Warning System. Answer: A circuit that warns of an event, requiring action from an operator or analyst. ⩥ FTA (Fault Tree Analysis). Answer: A method to analyze the causes of an end effect, which can be quantified by generating probability estimates and assigning them to events. ⩥ Graphical representation of FTA. Answer: A visual tool that aids in understanding the logic and facilitates the selection of points of interest to find root causes. ⩥ Monitoring and control. Answer: The process of overseeing and optimizing the safety performance of a complex system.
⩥ Parallel fault paths. Answer: Fault paths that can operate simultaneously within a system, effectively managed through FTA. ⩥ Sensitivity cases. Answer: Considerations for modifications to system components, architecture, and testing intervals. ⩥ Limitations of FTA. Answer: Challenges such as the need for separate fault trees for each top event and the time-consuming nature of the analysis. ⩥ Omissions in FTA. Answer: The possibility of failing to include certain failure event probabilities in the analysis. ⩥ Applications of FTA. Answer: Used in safety and reliability engineering to determine the probability of accidents, monitor system performance, and assist in system design. ⩥ Diagnostic tool. Answer: A function of FTA to identify and correct causes of the top event. ⩥ Impact of changing environment. Answer: The effect of environmental changes or duty cycle modifications on system design.
