Einhorn Reliability Calculator

The Einhorn Reliability Calculator calculates the Mean Time Between Stops (MTBS), Mean Down Time (MDT) and Availability (AVO) of n identical elements in parallel or series using the (r) out of (n) Einhorn equations. The units conform to the usual exponential error rate laws and their behavior are mutually independent. Mathematical analyses of the aspects of the system reliability prediction have appeared often [1][2][3][4]. Most of these analyses assume that errors of units are permanent i.e. the system is not repairable. This assumption applies well to missiles and satellites. In many cases we are interested in systems that can and will be returned to service following successful repair of the failure [4].

The input parameters Mean Time Between Failures (MTBF) of a device, Mean Recovery Time (MREC) of the system, Mean Time to Repair (MTTR) of the device, Fault Coverage Percentage of the device (CVGI), number of devices required for system operation, number of devices available to the system and any devices in "hot standby".

MTBF, MREC, and MTTR are measured in hours, and CVGI is measured fractionally from 0 to 1, i.e. 0.95.

[1] Balaban, H.S. "Some Effects of Redundancy on System Reliability", Proc on Reliability and Quality. Washington, D.C. pp 395-492, January 14-18, 1962.
[2] Backow, R.S. and Hunter, C.L. "Mathematical Models for System Reliability", Sylvanna Technologist, vol XIII, pp 4, January 1960.
[3] Dick, R.S. "The Reliability of Repairable Complex Systems Part A - The System Modeling Case", Proc Professional Group on Military Electronics, Washington, D.C., pp 111-150, June 26-28, 1961.
[4] Einhorn, S,J. "Reliability Prediction for Repairable Redundant Systems", Proceedings of the IEEE, pp 312-317, February, 1963.