Fatigue reliability assessment of small sample excavator working devices based on Bootstrap method

Abstract

To evaluate the fatigue reliability of the excavator working device, the fatigue tests of 2 sets of moving arm and bucket rod of medium-sized excavators with self-weight of 26000 kgwere carried out. The virtual augmented sample method (VASM) combined with Bootstrap method was used to analyze the reliability of the excavator working device under extreme small samples, and the interval and point estimations of life parameters were obtained. Based on the lognormal distribution of the excavator working device, the reliability evaluation model of the excavator working device was established, and reliability indexes, such as reliability function, failure distribution function, inefficiency function, reliable life and so on, were obtained. And the results of fatigue safety life under different confidence and reliability were calculated. The evaluation results show that the average failure time of the excavator working device is 6124 hours under the confidence of 75%, which provides an important reference for the design, the safety inspection and maintenance decision of the excavator working device.

Fatigue Life Data Fusion Method of Different Stress Ratios Based on Strain Energy Density

“…The strain energy density-fatigue life (W t -N f ) curve can be solved using a two-parameter power function model [43] as shown in Equation ( 7) or a three-parameter power function model [44] as shown in Equation (8). Formally, the three-parameter model has one more constant term than the two-parameter model, which can express the endurance limit of the model curve.…”

“…Solving fatigue damage problems in engineering structures requires fatigue test data to obtain large samples of data. It has been found that even if the fatigue test is conducted under the same conditions, the fatigue life obtained from the same material specimens has deviations, and the fatigue life has an unavoidable discrete nature [ 8 , 9 , 10 ]. The fatigue test has the features of a long cycle time and high cost; it is difficult to obtain large sample data that meet the requirements of traditional statistical methods.…”

Programmed system for fatigue life prediction of excavator turntables based on multi-body dynamics and finite element analysis

“…It not only bears its own weight but also effectively handles dynamic loads from excavation activities. Additionally, it is highly prone to fatigue fractures [ [5] , [6] , [7] , [8] ].However, the harsh operating environment and fluctuating loads can cause stress changes, potentially leading to fatigue failure [ [9] , [10] , [11] ].…”

Uncertainty for fatigue life of low carbon alloy steel based on improved bootstrap method

“…Researchers have developed different sampling methods for complex problems. For instance, Yang proposed an improved bootstrap method based on gray theory, 27 James introduced several new variants of the wild cluster bootstrap, 28 Shao improved bootstrap by using the virtual augmented sample method to analyze reliability, 29 and Chang proposed a parametric bootstrap approach to improve the Durbin‐Watson test, which is inaccurate for small samples 30 . The bootstrap method has been widely applied in various fields, such as medicine, 31 biology, 32 mechanical engineering, 33 aerospace, 34 and so forth.…”