Test Design Using Logarithmic Distributions (Statistical Analysis)*

Liaison: Martin Stryker

Reliability analysis is used in part and assembly design to determine if it will perform the intended function, without failure, for the required duration when installed and operated correctly in a specified environment. There are three parts to this project: first, quantitatively compare the current test design at Stryker Medical to that used at Stryker Instruments. Secondly, develop a reliability testing calculator that determines required testing parameters for accelerated simulated life tests, go-no go testing, testing longer than required life, and testing to failure. The variables involved are sample number, mean time to failure, confidence level, and reliability. Other variables may be used depending on the type of distribution (Weibull, single parameter logarithmic) to model behavior.

These parameters, if used, should have a physical meaning or must be related to other defined reliability parameters. Thirdly, using the new/chosen model and past test data, create a library of testing parameters according to part/assembly, failure type, and testing type, that may be used in future test design and analysis.

* Summary prepared by Michael Hernandez, Associate Project Manager, Stryker Medical, mhernand@med.strykercorp.com