PROGRAM LOAD SPECTRUM COMPILATION FOR ACCELERATED
LIFE TEST OF PARABOLIC LEAF SPRING |
Jie Zhang1, Jianwei Lu1, Weiduo Han1, Haibo Li2 |
1Hefei University of Technology 2Anhui Jianghuai Automobile Co. Ltd. |
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ABSTRACT |
A method of program load spectrum compilation suitable for ALT (accelerated life test) of parabolic leaf spring
was presented. In order to shorten the design and test period, road test is conducted on proving ground roads. The displacement
spectrum of shock absorber connecting the point of the parabolic leaf spring seat on a commercial vehicle exposed to roads
was obtained. The FEA (finite element analysis) method was used to obtain stress spectrum of hot spots on leaf spring by the
displacement spectrum, and the fatigue life of the leaf spring is predicted using Palmgren-Miner's rule. Statistical
characteristics of the amplitudes and means of the displacement spectrum is investigated. The amplitudes and means of
displacement spectrum found in experiment obey Weibull distribution and normal distribution respectively, and the
distributions of amplitudes and means are independent. Based on the Conover principle, the two-dimensional spectrum with
eight levels is established by applying the cycle extrapolation method, and then it is converted into one-dimensional spectrum
with the variable mean method. Follow the theory of equal damage, the program load spectrum is compiled suitable for bench
test of fatigue life of leaf spring. The method of program load spectrum compilation can provide reference for fatigue life test
and life prediction of parabolic leaf spring assembly. |
Key Words:
Parabolic leaf spring, Accelerated life test, Program load spectrum, Fatigue reliability, Durability test |
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