Strain‐based fatigue criterion for rubber damage under multimode loadings

Abstract

An accurate prediction of the fatigue life of a rubber product is based on a criterion. Since strain can be measured directly in rubber components during a test, it would help design engineers improve product performance effectively if the strain‐based damage criteria can achieve high accuracy. Hence, the experimental data on the AE42 and AE2 specimens were utilized to test the suitability of the proposed damage criterion for rubber materials. The criterion includes three principal components determined by both a strain range and a current strain. Data from AE42 specimens, made from styrene‐butadiene rubber, contained 40 cases, that is, tension, torsion, and tension‐torsion loadings. An S‐N curve was obtained, with a scatter band of 0.7 and a coefficient of determination R2 of 0.81. The curve could be useful at the design stage. A sample of AE2, made from natural rubber filled with carbon black, showed the location and orientation of the crack in a nonproportional case. The predicted location of the fatigue crack was consistent with the experimental observation and the crack orientation matched the experimental measurement, that is, the predicted angle of 33.4° versus the measurement of approximately 40°. It would be possible to combine the proposed approach with the critical plane method in nonproportional loadings to save significant CPU time: using the proposed approach to find the critical loading range and then using the critical plane method to find the maximum value of the required damage variables. More engineering cases are needed to further verify this proposed criterion.

FE and probabilistic analysis for rubber life estimation considering cracking energy density as a fatigue predictor

“…It is observed that these results agree very well with experimental data. 18 The safety zone is remarkably reduced as the reliability values increase.…”

“…Shanguann and Coworkers, 4 Belkhiria et al, 7 Zarrin-Ghalami and Fatemi 8,19 and Luo et al 17,18 employed strain-based fatigue criteria to assess fatigue damage. The Researchers in 4 and 7 found out that Green-Lagrange was the most appropriate parameter to evaluate fatigue time of rubber.…”

A unified probabilistic fatigue life prediction model for natural rubber components considering strain ratio effect

“…Equation (6) indicates that accurate estimation of parameters in the log-normal distribution model is the key to calculate the fatigue reliability of NR components. Based on the test results, the maximum likelihood estimation method is used to determine the parameters.…”

“…5 Establishing a rubber fatigue life prediction model (also called the S-N curve) is an effective method to obtain the fatigue life of rubber isolators. 6 Unlike the mature and highly-developed fatigue theory of metal materials, the fatigue life theory of NR components is still developing. 5 The behavior of NR materials is complex owing to their high deformability, quasi-incompressibility, and stress softening.…”

A simple fatigue methodology for filled natural rubbers under positive and negative R ratios

“…• Strain-based fatigue criteria: Shanguann and coworkers [2], Belkhiria et al [4], Wang et al [7], Zarrin-Ghalami and Fatemi [8] and Luo et al [9,10].…”