Tm - Life Test Data Analysis

VEM

Reliability Analysis of TM Life Test Data (Zuji Magnets)

Reliability Engineering

VEM Life Test Data Sl. No 1

St. Date

Total Qty

Failed

6. Oct. 2006

4

2

15. Nov. 2006

4

4

27. Nov. 2006

4

4

27. Dec. 2006

4

4

3. Feb. 2007 24. Feb. 2007

4 4

1 1

8. Mar. 2007

4

2

23. Mar. 2007

4

3

Total

32

21

2

3

4 5 6 7

8

Average Cycles

Cycles 18000 31200 18000 25200 39600 39600 15480 15480 24120 24120 18300 30300 30300 30300 2600 11100 13350 27750 11100 18300 28100

22490.48

Reliability Engineering

Failure SLIPS

STRUCK

VEM

Weibull Analysis on the TM Life Test Data (Zuji Magnets)

Life Data 1. Failed Samples (< 50,000 Cycles) : 21 2. Censored Samples (>50,000 Cycles) : 11 3. Total Samples under Life Test

: 32

Analysis Parameters (MINITAB) 1. Estimation Method : Max. Likelihood 2. Distribution : Weibull Parameter Estimates 1. Scale : 44822 2. Shape : 1.4721 3. MTTF : 40554 Scale is also called as CHARACTERISTIC LIFE For the Weibull distribution, the characteristic life is equal to the scale parameter, This is the time at which 63.2% of the product will have failed. So, 63.2 % of TM fails by 44822 Cycles Shape value of 1.4721 implies mild wear-out characteristics Reliability Engineering

VEM Percentile is How long it takes for 10% of the units to fail, 20% of the units to fail, 20% of the units to fail............

1.05 % of samples fail by 2040 Cycles So, The No. of Cycles required for 10 % of the samples to fail is 9728 Cycles, for 50 % of failure is 34949 Cycles and for 90 % of the sample to fail is 78952 Cycles.

Reliability Engineering

Percentage 1 1.05 2 3 4 5 6 7 8 9 10 20 30 40 50 60 70 80 90

Percentile 1973 2040 3170 4189 5111 5968 6778 7553 8300 9024 9728 16191 22261 28409 34949 42239 50840 61913 78952

VEM Reliability R(t): The probability that an item will perform its intended function without failure under stated conditions for a specified period of time The R(50,000) for TM is 0.3089

Reliability Engineering

Cycles 1000 2000 3000 4000 5000 6000 7000 8000 9000 10000 20000 30000 40000 50000 60000

R(t) 0.9963 0.9898 0.9816 0.9720 0.9613 0.9496 0.9372 0.9241 0.9103 0.8961 0.7374 0.5749 0.4293 0.3089 0.2151

VEM

Reliability Engineering

VEM Conclusions : 1. 63.2 % of TM fails by 44822 Cycles. 2. Shape value of 1.4721 implies mild wear-out characteristics. 3. 1.05 % of samples fail by 2040 Cycles. 4. Reliability, R(50,000) for the TM is 0.3089. 5. Mean Time To Failure is 40554 Cycles.

Reliability Engineering