Introduction to Reliability Allocation in Reliability Workbench

Reliability Allocation is a method of apportioning a system target reliability to sub-systems and components. It is a useful tool at the design stage for determining the required reliability of equipment in order to achieve a given system reliability target.

Using Reliability Allocation

During the design phase of a product Reliability Allocation may be used to set reliability goals for individual sub-systems. The simplest method is simply to distribute the reliability goal equally among all sub-systems. However, this rarely gives the best distribution of reliability objectives for all sub-systems. It is better to allocate reliability values between the sub-systems based on complexity, criticality, achievable reliability, or other factors that are deemed appropriate.

The Allocation module within Reliability Workbench supplies the user with six methods for assigning sub-system reliability values:

  • Non-restricted equal allocation
  • Non-restricted graded allocation
  • Non-restricted proportional allocation
  • Non-restricted redundancy proportional allocation
  • Non-restricted reliability re-allocation
  • Restricted direct research allocation
  • Extended graded allocation

The Reliability Allocation module enables a system hierarchy to be constructed where sub-systems may be broken down in detail to component level. This allows a complete system allocation model to be constructed.