Modeling and Simulation (M&S) Impact on Reliability Basic Thoughts

Transcription

1 Modeling and Simulation (M&S) Impact on Reliability Basic Thoughts Briefing for: Ground Vehicle Reliability Panel DoD Maintenance Symposium 27October 2008 Jerry Moeller US Army TACOM , 1/10

2 Current State of Reliability Top Top Level Managements Assessment 6 Dec Dec Assistant Secretary of of the the Army Army (Acquisition, Logistics and and Technology) Reliability MEMO MEMO to to Army Army PEOs/PMs Emerging data data shows shows that that a significant number number of of US US Army Army systems systems are are failing failing to to demonstrate established reliability requirements during during operational testing testing and and many many of of these these are are falling falling well well short short of of their their established requirement Jul Jul Under Under Secretary of of Defense Defense (Acquisition, Logistics and and Technology RAM RAM MEMO MEMO to to Acquisition Executives In In recent recent years, years, there there has has been been an an increasing trend trend within within the the Department of of weapon weapon systems systems not not achieving the the required reliability during during development testing testing and and subsequently being being found found unsuitable during during Initial Initial Operational Test Test and and Evaluation. Also, Also, higher higher than than anticipated ownership cost cost points points to to insufficient reliability engineering activities and and logistics logistics planning during during the the program acquisition phase. phase. This This trend trend indicates that that RAM RAM was was not not adequately designed into into systems. Reliability Improvement Needed Needed Now Now 2/10

3 Consider the Use Physics of of Failure (PoF) in in Materiel Design The ultimate long term goal is for DoD system developers to consistently predict & design-in reliability at the system and component levels Proven successful with high Return on Investment Electronic PoF Mechanical PoF + Required for Ultra-reliability required in AAN Ultra-Reliable System Increase Reliability Reduce Reduce O&S O&S Costs Costs Focus Focus Testing Testing Increase Readiness Supports RCM RCM Support CBM+ CBM+ PoF-Based PoF-Based M&S M&S Analysis Analysis Focuses Focuses on on Fatigue Fatigue 3/10

4 Analytical Elements of of Mechanical PoF PoF Design Objective: Identify the fatigue spots on critical components, iteratively modify the design of the those components to assure Ultra High Reliability Solid Modeling Tool Dynamics Simulation Tool FEA Tool w/pre & Post Processor Fatigue Analysis Tool Examples: Pro/Engineer I-deas Solid Works Examples: DADS ADAMS Examples: NASTRAN ABAQUS ANSYS Pro/Mechanica Examples: MSC/Fatigue (N-Code) U.of Iowa DRAW LMS FALANCS An integration of these tools 4/10

5 The Focus of of Mechanical PoF-based M&S Predicting early early in in the the design design process process what what testing testing can can not not afford afford to to reveal reveal Hazard Rate Failure Curve for Mechanical Equipment Quality Defects Wear-out w/ Random Overstress Main Main causes causes of of mechanical mechanical wear-out: wear-out: Fatigue Fatigue Wear Wear Corrosion Corrosion Testing Mechanical PoF M&S Time Reliability Reliability testing testing reveals reveals only only a a fraction fraction of of the the failures failures of of the the total total materiel materiel life life cycle cycle This This overlap overlap is is where where testing testing can can be be focused focused using using Mechanical Mechanical PoF PoF M&S M&S Mechanical Mechanical PoF PoF M&S: M&S: Main Main focus focus is is on on understanding understanding and and predicting predicting wear-out wear-out failures failures throughout throughout the the entire entire materiel materiel life life cycle cycle Mechanical PoF PoF is is required to to assess assess life life cycle cycle reliability 5/10

6 Reliability Centered Maintenance (RCM) Most Most Weapon s s Component Can Can Not Not be be Designed to to Last Last the the Life Life Cycle Cycle The purpose of Reliability Centered Maintenance (RCM) is to formulate Failure Management Strategies that allow assets to continue operating at the users desired level of reliability performance as opposed to what the asset was designed to do. The DoDapproved RCM process includes identifying the following items in sequence. PoF PoF helps helps in in defining maintenance intervals #6 #6 6/10

7 How can PoF Help RCM Predicting Failure: On-Condition On-Condition tasks are performed to identify signs of impending failure and can be performed using: Human senses Sophisticated monitoring equipment; or Continuous monitoring by sensors being applied directly to equipment Condition Based Maintenance Examples of On-Condition tasks are: Performing vibration analysis: detects increased vibration signatures. Taking oil samples: Sample results indicate increased water content and additive depletion. Measuring brake pads: Identifies how much of the pad is remaining. Monitoring # duty cycles endured by key components The point of an On-Condition task is to identify when action is required based on the evidence of need (e.g. detection of the Potential Failure Condition). How often an On-Condition task is performed depends on the P-F Interval. Following is a discussion of the P-F Curve and the P-F Interval. PoF PoF can can help help in in defining the the P-F P-F Interval 7/10

8 What can PoF- do for RCM Predicting Failure: The The P-F PP-F F Curve Curve This graph depicts the P-F Curve. The graph below is a typical wear out example such as brake pads. The X axis is Age, which can be measured in any number of units such as calendar time, miles, operating hours, cycles, etc. The Y axis is Resistance to Failure. P is the Potential Failure Condition, defined as evidence of an impending failure. F is the Functional Failure, as defined by the user. Resistance to Failure P: Potential Failure Condition Age F: Functional Failure Use Use PoF PoF to to define define the the P-F P-F Curve Curve for for Critical Critical Components 8/10

9 Condition Monitoring s s Basic Problem Not All Duty Cycles are not Created Equal Because of of the the limitation of of sensor sample rates and and data data storage on on in- inservice vehicles, algorithms and and metrics need need to to be be developed that that would use use simplified counting schemes to to compare actual damage cycles on on in-service vehicles to to pre-calculated damage from various environmental conditions as as calculated by by PoF PoF failure mechanism models. Approach: Approach: Categorize Categorize mission mission scenarios scenarios (primary, (primary, secondary, secondary, etc) etc) and and run run PoF PoF for for each each Initialize Initialize damage damage accumulation accumulation model model with with mission mission scenario scenario results results On-board On-board sensors sensors used used to to determine determine duration duration of of each each scenario scenario Transfer Transfer sensor sensor data data to to damage damage accumulation accumulation models models Damage Damage accumulation accumulation models models keeps keeps running running total total % of of life life is is used used Spare Spare parts parts ordered ordered and and maintenance maintenance performed performed before before component component failure failure Accurately Account for for Wear Wear to to Check Check Against Against the the P-F P-F Curve Curve 9/10

10 Use M&S Driven Mechanical PoF A Helper in in Achieving High Reliability Use M&S driven PoF Design Analysis to: 1) 1) Initially Find the High Reliability Configuration 2) 2) Define RCM P-F Curve to to Ascertain When a Critical Component Need to to be Replaced 3) 3) Develop Damage Accounting Algorithms for Condition Monitoring of of Critical Components Comments/Questions?? 10/10