SRC Forum - Message Replies

Forum: Reliability & Maintainability Questions and Answers

Topic: Reliability & Maintainability Questions and Answers

Topic Posted by: Reliability & Maintainability Forum (src_forum@alionscience.com )
Organization: System Reliability Center
Date Posted: Mon Aug 31 12:47:36 US/Eastern 1998

Original Message:

Posted by: Mehta (vardhman_mehta@hotmail.com )
Organization:TELCO
Date posted: Sat Feb 22 3:23:28 US/Eastern 2003
Subject: Reliability measurement for Automobile
Message:
I was hoping someone could help me out. 1. What is the best indice for specifying reliability of a car? Should we take into consideration of Power train,chassis, Electrical items(horn,headlamps,blinkers, etc...), etc all of the components of the system or only some of the subsystems as mentioned above? 2. How can i predict reliability of new development car? Could you please provide an example?

Reply:

William H. Crowell Subject: Reliability Measurement for Automobiles
Reply Posted by: (wcrowell@alionscience.com )
Organization: Reliability Analysis Center
Date Posted: Wed Feb 26 15:32:15 US/Eastern 2003
Message:
When performing a reliability model on an Automobile, all of the components should be considered in the analysis, unless the study specifies that only specified components are to be studied such as the Power Train.

A good publication that provides general reliability principles and analysis techniques published by the Reliability Analysis Center (RAC) is the Reliability Toolkit: Commercial Practices Edition. While this publication will not directly answer your question, it does provide insight into analyses that can be performed to assess the design of a new automobile. For a complete directory of RAC publications go to: http://rac.alionscience.com/rac/jsp/webproducts/products.jsp

Also, the Society of Automotive Engineers (SAE) has developed several papers that discuss Automotive Reliability.

Potential Failure Mode and Effects Analysis in Design (Design FMEA) and potential Failure Mode and Effects Analysis in Manufacturing and Assembly Processes (Process FMEA) and Effects Analysis for Machinery (Machinery MTBF)
SAE Document Number J1739, August 2002

Papers published before February 1998 are not listed on the SAE website. They are available with SAE Internet and CD-ROM products or by contacting SAE Customer Service at 1-877-606-7323 (toll-free in the U.S. and Canada) or 724/776-4970.

Additional suggested reading:

Reliability Prediction and Evaluation of Electronic Devices, Subassemblies, and Systems for Automotive Applications
SAE Technical Paper 830408

Development of Reliability Prediction Models for Electronic Components in Automotive Applications.
SAE Technical Paper 840486

Automotive Electronic Reliability Prediction
SAE Technical Paper 870050

Reply:

William H. Crowell Subject: Repair Incidents
Reply Posted by: (wcrowell@alionscience.com )
Organization: Reliability Analysis Center
Date Posted: Wed Feb 26 16:06:28 US/Eastern 2003
Message:
As a rule of thumb a Rough Measurement of Repair Incidents per 100 vehicles per year or 10,000 miles would be:
Less than 50 Repairs is Very Good
50 to 100 Repairs is Good
100 to 150 Repairs is Fair
Greater than 150 Repairs are Poor

All components are included under most first year warranties.
To perform a Reliability Modeling Analysis you should use the following:
Use Historical Data
Use Stress Test data
Use Sample Long Term Test Data
Use Mechanical Parts Data NPRD-95
Use Electrical Parts Data EPRD-97