OCTOBER 19-20, 2012 - YMCA University of Science & Technology

Proceedings of the National Conference on
Trends and Advances in Mechanical Engineering,
YMCA University of Science & Technology, Faridabad, Haryana, Oct 19-20, 2012
= (1)
Where, N= 1000 stress cycles to fail at 310.275 N/mm2, (copper reference point)
S2= 310.275 N/mm2 (stress reference point)
b = 6.4 (reference slope of fatigue curve for copper lead wire with k= 2)
S1 = wire stress from the analysis
N1 = No of cycles before the failure of wire and is given by the equation;
N1 =N2 (2)
Wire life in hours = (3)
The equations 2 and 3 will be directly included in the macro with constant values N2, S2, and b for copper lead
wire. The stress S1 will be obtained from vibration analysis and used to calculate the number of cycles to failure.
These N1 and natural frequency (Fn) will be utilized automatically to calculate life in minutes.
6. Results and Discussion
Simulation is carried for the capacitor with copper leads under 2.33 G vibrations loading by running a coded
program generally called macro in suitable analysis tool. To estimate failure probability, fatigue life calculator
was incorporated in the program. In this section detailed discussion of the results obtained from the simulation
are made with suitable graphs.
6.1 Sensitivity Analysis
Sensitivity plots are important in order to improve the design as more reliable and better quality product, or to
save money while maintaining the reliability or quality of product. It is possible to draw sensitivity plot for any
random output parameter of a component. In this case natural frequency and life are the two important output
parameters. Sensitivity plots for the Natural Frequency and Life of component are shown in Fig.6 and Fig.7
respectively. It consists of both bar chart and pie chart. Sensitivities are ranked so the random input variable
having the highest sensitivity appears first. From the sensitivity plot for natural frequency it can be concluded
that natural frequency of the capacitor is more sensitive to lead length, lead radius. Similarly sensitivity plot for
life (number of minutes to failure) clearly represents that lead radius is directly proportional to failure of
component, and hence lead radius is the most significant parameter for the failure of capacitor.
Fig. 6 Sensitivity Plot for Natural Frequency
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