FAULT TREE ANALYSIS REPORT FOR THE AUTOMATIC BRAKE SYSTEM. Prepared by

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1 FAULT TREE ANALYSIS REPORT FOR THE AUTOMATIC BRAKE SYSTEM Prepared by Sample Company 111 Foothill Blvd. Suite E-156 La Canada Flintridge, California July 2002 Copyright 2002 by Probabilistic Software, Inc.

2 TABLE OF CONTENTS Section Title Page 1.0 INTRODUCTION AND SUMMARY Scope Objectives Functional Description APPLICABLE DOCUMENTS Military Specification Documents Sample Company Documents Other Documents FAULT TREE ANALYSIS (FTA) REQUIREMENTS Subsystem Safety Program Plan Requirements Procurement Specification Automatic Brake System Requirements Fail Operational Requirements Automatic Brake System Reliability Quantitative Requirements FAULT TREE ANALYSIS Fault Tree Analysis Methodology Detailed Fault Tree 22 Copyright 2002 by Probabilistic Software, Inc. 2

3 TABLE OF CONTENTS Section Title Page 4.3 Fault Tree Symbols Mathematical Model of The Automatic Brake System 23 Fault Tree Diagram 5.0 ANALYSIS RESULTS SUMMARY 35 Table 1 Comparison Matrix of FTA Specified Top Event 2 Quantitative Failure Probability Requirements Versus Calculated Values Figure 1 Automatic Braking System Exploded View Assembly Drawing 4 2 Automatic Brake System Failure Fault Tree Diagram 5 Copyright 2002 by Probabilistic Software, Inc. 3

4 1.0 INTRODUCTION AND SUMMARY This document presents the Sample Company Fault Tree Analysis (FTA) Report performed on the Automatic Braking System (ABS). It was prepared in accordance with the Sample Company Automatic Braking System (ABS) Procurement Specification, Document No. ABC1111A, Paragraph , Reliability ; the Sample Company Engineering Statement of Work, Paragraph 1.7.6, "Fault Tree Analysis"; the Sample Company s Subsystem Safety Program Plan, Document No , Paragraph 5, Hazard Analysis ; the Data Item Description No. E-348, "Fault Tree Analysis", dated March 29, 1977; and the Sample Company document "Introduction to Fault Tree Analysis", SC-ABC1111A, Revision A, dated April 10, The results of this analysis indicate that the ABS and its assemblies meet the safe operation requirements of its Procurement Specification. This statement is fully supported by the ABS Fault Tree Diagrams and Failure Probability Calculations presented in the mathematical models, the Fault Tree Diagrams of Section 4 and the summary matrix of specified quantitative requirements versus calculated values in Table 1. This example is not a complete report. The remaining text and mathematical models will be provided upon the purchase of this report. Continue to scroll down to view an example mathematical model and fault tree diagram. Copyright 2002 by Probabilistic Software, Inc. 4

5 4.4 Mathematical Model of The Automatic Brake System Fault Tree Diagram Since all the events in the fault tree of Figure 1 are independent, the event probabilities are as follows: P( C) = P( D) + P( E) [ P( D) x P( E)] PTop ( ) = PA ( ) xpb ( ) xpc ( ) Where P( A)= Probability of Event A, Servo Valve Driver Failure, 1 e λ At, / λ A = Failure rate of Servo Valve Driver, U1, Hybrid Current Driver, / 10 6 Hours. t = Risk Exposure Time, seconds or 7/ 10 6 hours, for all events. P( B) = Probability of Event B, Shutoff Valve Watchdog Failure, 1 e B t, / λ B = Failure rate of Shutoff Valve Watchdog Circuit, U2, Eraseable Programmable Logic Device (EPLD), / 10 6 hours. t = 7/ 10 6 hours. P( C) = Probability of Event C, Display Electronics Unit (DEU) fails to display ABS fault status, D E PD ( ) + PE ( ) [ PD ( ) xpe ( )], ( 1 e ) + ( 1 e ) Dt Et [( 1 e ) x( 1 e )], / P( D) = Probability of Event D, ABS Arm Watchdog Failure, 1 e D t, / t t Copyright 2002 by Probabilistic Software, Inc. 5

7 λ D = Failure rate of the ABS Arm Watchdog Circuit, U3, EPLD, / 10 6 hours. t = 7/ 10 6 hours. P( E)= Probability of Event E, Servo and Shutoff Valve Monitor Failure, 1 e E t, / λ E = Failure rate of the Servo and Shutoff Valve Monitor Circuit, U4, EPLD, / 10 6 hours. t = 7/ 10 6 hours. Therefore, P( Top) = P( A) x P( B) x P( C) = ( / 10 )( / 10 )( / 10 ) = / or zero. Copyright 2002 by Probabilistic Software, Inc. 7

Basic manual: Contents ELECTRONICALLY CONTROLLED HYDRAULIC SYSTEMS

Basic manual: Contents ELECTRONICALLY CONTROLLED HYDRAULIC SYSTEMS TECHNICAL NOTE Edition Anglaise 77 11 205 445 JUNE 1999 Type 3239A Service 0422 Sub-section JE0 X BOSCH 5.3 ABS WITH SPEED INFORMATION FUNCTION Engine: Gearbox: XXX XXX Basic manual: N.T. 3034A This note