On the need to decompose fatigue strain signals associated to fatigue life assessment of the AISI 1045 carbon steel

• Comparing the fatigue behaviour under three types of constant loading.
• It is a need to assess the fatigue life using a new statistical-based analysis.
• Higher stresses induced higher statistical (I-kaz) coefficient values.
• It is suggested that the I-kaz technique is capable to assess fatigue failure.

The evaluation of a new statistical-based analysis is discussed in this paper, leading to the fatigue life assessment at three different applied stresses during the cyclic testing procedure. Fatigue tests were performed following the standard ASTM: E466-07. These tests involve a strain gauge being attached to the specimen. For this test, AISI 1045 carbon steel was used as material due to its wide application in automotive and machinery industries. Fatigue tests were performed at three different stress levels of 305 MPa, 325 MPa, and 345 MPa with the testing frequency of 8 Hz, and the strain signals were collected accordingly. The Integrated Kurtosis-based Algorithm for Z-filter (I-kaz) approach, which provides its coefficient and three dimensional graphics, was utilised to define a statistically-based fatigue behaviour pattern. The I-kaz technique was used to extract strain signal patterns at the respective low, medium, and high frequency ranges for each signal at specific applied testing stress level. Results showed that highest strain amplitude occur at the low frequency range, suggesting the capability of I-kaz to identify fatigue damage pattern of metallic materials using statistical representation.