Forum: Reliability & Maintainability Questions and Answers

Add a Message About this forum
Newer messages are at the top

Previous 5 messages

Posted by: Bryant
Date posted: Fri Dec 6 8:51:22 US/Eastern 2002
Subject: MTBF for complex electromechanical system
Message:
I just want some advice on which distribution should i use to model complex electromechanical system for example army vehicle? Some advice me to use exponential distribution. Can advice?
Secondly MTBF only applies to exponential distribution but in actual fact, the vehicle will wear out sooner or later. So for my spares provisioning model should i use MTBF or MTTF values to be more realistic?

Replies: (list all replies)
MTBF for complex electromech system
C. Jayaraman Fri Dec 6 12:54:20 US/Eastern 2002
No field data
Bryant Sat Dec 7 21:59:54 US/Eastern 2002

Reply to this message


Posted by: Andrew Rowland (darowland@aep.com )
Date posted: Wed Dec 4 12:26:23 US/Eastern 2002
Subject: Life Data Analysis
Message:
I am trying to perform life data analysis which I plan to roll-up to an RBD. I am doing this to provide examples in an attempt to convince management that these analyses are important for an organization concerned with reliability. Obviously, it will be more poignant if I use actual plant systems, but I want to ensure that my results are the best they can be. In light of this, I have a couple of questions. I thank you in advance for your input.
The system I have chosen to model is comprised of four identical “channels” of electronics. System level functions are satisfied by a 2-out-of-4 arrangement of the channels. The system has been in service for 25 years (late 70’s). Use of a computerized failure reporting system began in May 1991. Thus, the date of failures and time taken to repair each failure after May 1991 are easy to obtain. However, there is no failure data for the system prior to May 1991. The only thing I know for certain is that each channel operated failure free from May 1991 until the first failure was reported. Intuitively, the first failure found in the computerized system for each channel would be a right censored data point. The time of suspension would be the date of failure minus May 1991. Is this the correct way to treat this situation when performing life data analysis? Would the model developed only be applicable to a channel during the 15-25 year portion of it’s life? That is, I couldn’t expect my model to describe the behavior of a channel that was “brand new”.

Replies: (list all replies)
Life Data Analysis
Coit Wed Dec 4 14:24:57 US/Eastern 2002
Maybe a RGT model?
Joe Dzekevich Fri Dec 6 14:50:49 US/Eastern 2002

Reply to this message


Posted by: Wayne
Date posted: Fri Nov 29 10:37:21 US/Eastern 2002
Subject: MTBF or service life??
Message:
I often see supplier's specifications on things like for example a motor having an MTBF of 150,000hrs with a service life of 10 yrs. The MTBF greatly exceeds its service life. Is that possible? I thought that MTBF should be lower than service to make sense?
So which figure do i use as my input for my reliability analysis of a complete system? MTBF or service life?

Replies: (list all replies)
Service Life
Joe Dzekevich Mon Dec 2 16:34:50 US/Eastern 2002
MTBF or Service Life?
Ken Wed Dec 4 8:41:22 US/Eastern 2002
MTBF or service life?
C. Jayaraman Fri Dec 6 13:06:34 US/Eastern 2002

Reply to this message


Posted by: John Hoegbraathen (john.sigurd.hogbrathen@kongsberg-simrad.com )
Organization:Kongsberg Simrad AS
Date posted: Mon Nov 25 9:24:04 US/Eastern 2002
Subject: Test for ESD failure
Message:
Is it any known test method, described by a standard or any other paper, to be sure of whether a electronic component or circuit is damaged by ESD or not.

Replies:
Test for ESD Failures
William H. Crowell Mon Nov 25 10:43:58 US/Eastern 2002

Reply to this message


Posted by: Wee Teck Hoon (wteckhoo@dso.org.sg )
Date posted: Fri Nov 22 1:41:47 US/Eastern 2002
Subject: Integrated Diagnostics
Message:
Appreciate anyone who can enlighten me and refer me to good references on the subject of Integrated Diagnostics.

Replies:
Integrated Diagnostics
BWD Mon Nov 25 15:15:41 US/Eastern 2002

Reply to this message


Next 5 messages

| 1...5 | 6...10 | 11...15 | 16...20 | 21...25 | 26...30 | 31...35 | 36...40 | 41...45 | 46...50 | 51...55 | 56...60 | 61...65 | 66...70 | 71...75 | 76...80 | 81...85 | 86...90 | 91...95 | 96...100 | 101...105 | 106...110 | 111...115 | 116...120 | 121...125 | 126...130 | 131...135 | 136...140 | 141...145 | 146...150 | 151...155 | 156...160 | 161...165 | 166...170 | 171...175 | 176...180 | 181...185 | 186...190 | 191...195 | 196...200 | 201...205 | 206...210 | 211...215 | 216...220 | 221...225 | 226...230 | 231...235 | 236...240 | 241...245 | 246...250 | 251...255 | 256...260 | 261...265 | 266...270 | 271...275 | 276...280 | 281...285 | 286...290 | 291...295 | 296...300 | 301...305 | 306...310 | 311...315 | 316...320 | 321...325 | 326...330 | 331...335 | 336...340 | 341...345 | 346...350 | 351...355 | 356...360 | 361...365 | 366...370 | 371...375 | 376...380 | 381...385 | 386...390 | 391...395 | 396...400 | 401...405 | 406...410 | 411...415 | 416...420 | 421...425 | 426...430 | 431...435 | 436...440 | 441...445 | 446...450 | 451...455 | 456...460 | 461...465 | 466...470 | 471...475 | 476...480 | 481...485 | 486...490 | 491...495 | 496...500 | 501...505 | 506...510 | 511...515 | 516...520 | 521...525 | 526...530 | 531...535 | 536...540 | 541...545 | 546...550 | 551...555 | 556...560 | 561...565 | 566...570 | 571...575 | 576...580 | 581...585 | 586...590 | 591...595 | 596...600 | 601...605 | 606...610 | 611...615 | 616...620 | 621...625 | 626...630 | 631...635 | 636...640 | 641...645 | 646...650 | 651...655 | 656...660 | 661...665 | 666...670 | 671...675 | 676...680 | 681...685 | 686...690 | 691...695 | 696...700 | 701...705 | 706...710 | 711...715 | 716...720 | 721...725 | 726...730 | 731...735 | 736...740 |

Add a Message About this forum