Forum: Reliability & Maintainability Questions and Answers
Posted by: Mehta (firstname.lastname@example.org )
Date posted: Sat Feb 22 3:23:28 US/Eastern 2003
Subject: Reliability measurement for Automobile
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?
Posted by: Hari (email@example.com )
Date posted: Sat Feb 22 2:59:45 US/Eastern 2003
Subject: Difference between Reliability and Durability
I am hoping someone could help me out.What is the difference between Durability and Reliability.(Along with some practical example)? How can we specify the both for components?
Posted by: Sadat
Date posted: Thu Feb 20 9:46:06 US/Eastern 2003
Subject: TL9000 Return Rates
Is anyone using TL9000 for tracking field reliability performance? I am wondering if we can compare our Telcordia based prediction of return rates (i.e. based on MTBF) to TL9000 metrics like Initial Return Rate (IRR) and Long Term Return Rate (LTR)? My concern is that predictions are time-based while the TL9000 metrics are population-based. Any general view of TL9000 as a reliability benchmark will also be appreciated.
Posted by: raja rizwan imtiaz (firstname.lastname@example.org )
Date posted: Sun Feb 16 0:57:10 US/Eastern 2003
Subject: functinal failure of safety valves
Recently, we have faced recurring pressure safety valve popping problem in few of the safety valves installed in high pressure steam service. While conducting safety valve failure investigation, it was observed that the problematic psv's spring has reduced in height about 7.0mm compared to the original (new) spring. original spring height = 207 mm and the used (old) measured spring height = 200mm
Currently, we are using only visual inspection criteria for the replacement of safety valve critical parts i.e. spring, spindle etc. However, we are looking for introducing the dimensional criteria as well to avoid such failures. If someone help answer following · Are you applying dimensional measurement criteria for the psv's critical parts or only visual inspections are done to adjudge the parts fitness. · What is the dimensional measurement criteria for spring replacement. Example could be for any service.
Posted by: Sadat (email@example.com )
Date posted: Fri Feb 14 12:46:51 US/Eastern 2003
Subject: DRAM Error Rates
I was hoping someone could help me out. We have recently seen a problem where we are getting high levels of bit errors from the "persistent memory" after a reset. Do you have statistics that would show what bit error rate we should expect if DRAM refresh was not done? Do you know if lack of DRAM refresh could cause bits to go 0->1 as well as 1->0?