Hdrramsmodelling

RAMS Modelling

RAMS, short for Reliability, Availability, Maintainability and Safety, is nowadays also commonly known as Dependability & Safety, or Systems Assurance. It is a discipline that is inherent in many technical fields, such as mechanical, electrical, software, systems, human factors and operations.

RAMS analysis is used to determine whether a system meets targets or required levels of performance and also allows sensitivity studies to be undertaken for the identification of critical components. Thus performance can be improved for optimum costs and modifications proposed that will lead to improved system availability and/or safety.

The numerical techniques employed to calculate the probability of a given event occurring, or protective measures failing, can be combined with consequence analysis to quantify risk. Therefore, as well as stand-alone studies, RAMS analysis frequently forms an integral part of Quantitative Risk Analysis and Safety Cases.

Techniques

apm provides expert RAMS modelling services through the application of a comprehensive selection of techniques, including:

Reliability:

  • Deterministic Reliability Assessment
  • Reliability Prediction, e.g. Systems Reliability and Mean Time Between Failures
  • Failure Modes Effects and Criticality Analysis (FMECA), including Functionality Analysis
  • Fault Tree Analysis & Reliability Block Diagrams
  • Reliability Critical Items List
  • Human Error Analysis
  • Common Cause / Mode Analysis
  • Time-Dependent System Reliability

Availability and Maintainability:

  • Availability & Maintainability Prediction
  • Maintenance Task Analysis, including Mean & Maximum Corrective & Preventative Maintenance Time
  • Mean Time To Repair (MTTR) Analysis
  • Maintainability of Design Analysis
  • Fault Detection, Isolation and Recovery (FDIR) Analysis
  • Spares Optimisation
  • Maintenance FMECA
  • Life Cycle Cost (LCC) Analysis

Safety:

  • Design and Operations Hazard analysis, e.g. HAZOP Studies
  • Determine Safety Assessment
  • Quantified Risk Assessments / Probabilistic Safety Assessments
  • Safety Integrity Levels (SIL) Verification
  • Cost Benefit Analysis
  • Event Tree Analysis
  • ALARP Analysis
  • Safety Critical Items List

Standards

In addition to the ISO and US Military RAMS and Dependability standards, apm has implemented specific industry standards into RAMS and Life Cycle activities, including the railway RAMS standards EN50126 and EN50128.

Analysis Tools

apm uses a range of commerical and in-house tools when performing RAMS analysis, using either Monte Carlo simulations or analytical methods, including:

  • In-House Software: FMECA, HAZOP ans Weibull analysis
  • Isograph Software: FaultTree+, AvSim+, Reliability Workbench, Hazop+ and Weibull
  • Relex Software: Fault & Event Tree Methodology, FMECA, Reliability Block Diagram, Reliability Prediction and Weibull
  • Jardine Software: MAROS