This Standard establishes uniform requirements and criteria for performance-based System Reliability Modeling, including planning, performing, documenting, and evaluating. Although it is a common industry practice for reliability modeling to be performed using computerized tools, this Standard does not mandate that any particular computerized methodology be used.

Purpose

The primary purpose of System Reliability Modeling is to develop mathematical or simulation models to be used for probabilistic apportionments or predictions based on the collective reliability characteristics of all the functional items required for a system to successfully complete its mission. The baseline system reliability model consists of mathematical or simulation models for the following system attributes.

— system hierarchical functional flow

— system operating modes and the mission timeline

— functional to physical association of each item in the system, to include as a minimum:

— all electrical, electronic, and electromechanical (EEE) items that perform essential functions in each specified mission time period or operating cycle, e.g., switches and sensors that control restorable functions,

— all mechanical, pneumatic, pyrotechnical, and structural items that perform essential functions in each specified mission time period or operating cycle

— system-level effects due to the loss of each functional item in the system

— inherent hazard rate or probability of failure for each functional item in the system

The primary output of the system reliability model is the system reliability prediction. The reliability model may be developed in either a textual or graphical form to represent the mathematical expressions or simulation instructions that are used to output probabilities.

System Reliability Modeling is particularly useful in determining where the projects reliability improvement resources should be applied. For example, reliability modeling of the systems inherent or operational reliability capability, using as inputs available engineering data modified to reflect mission environments and usage, will identify where changes in the existing design are required to meet system reliability requirements.

The graphical form of the reliability model is the Reliability Block Diagram (RBD). The RBD provides a concise and orderly method for visualizing the reliability characteristics, both individually and collectively, of all the functional items in the system. A system RBD may be developed starting from either the functional item level (bottom-up) or the system level (top-down). However, the mathematical expressions or simulation instructions are defined at the functional item level, and are combined in a bottom-up fashion. The effort required to perform system reliability predictions is dependent on the number and complexity of the reliability blocks in the RBD. A reliability block is the graphical representation of the mathematical or simulation model used to estimate the reliability of a system component.

Customers who purchased AIAA S-102.2.2
also purchased

• AIAA S-102.1.4 : Performance-Based Failure Reporting, Analysis jsessionid=AMYcdVNv3QYFv-zdjWXZnQ**.app22?event=DOCUMENT_DETAILSreturn true" onMouseout="window.status=' ';return true">AIAA S-102.1.5 : Performance-Based Failure Review Board (FRB) Requirements
• AIAA S-102.2.4 : Performance-Based Product Failure Mode, Effects and Criticality Analysis (FMECA) Requirements
• AIAA S-102.2.5 : Performance-Based Sneak Circuit Analysis (SCA) Requirements

See More Documents