Fatigue remaining life estimation for remanufacturing truck crane Jib structure based on random load spectrum

Quantitative fractography is the important tool for evaluating the fatigue propagation life about material research and manufacturing process perfect, it is very useful in the circumstances that crack expands inside of the material or the crack cannot be observed because of the hidden part of the component. In-service components are usually suffered different load spectrums, and the fracture characteristics are combined created by random load spectrum and block spectrum, which are beach marks, small beach marks and fatigue striations. The most important thing for fractography quantitative analysis is to confirm the parameter used for evaluating the fatigue life and determine the relationship between the parameter and load spectrum. The relationships between different fracture characteristics and load spectrums are analyzed, and the selection means of characteristic parameter for different load spectrums are proposed. This paper also discussed a case of fatigue propagation life estimation of some aircraft lower wall panel suffered in-service aircraft flight load spectrum.

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Load Spectrum Compiling and Fatigue Life Estimation of the Automobile Wheel Hub

Recent Patents on Mechanical Engineering ◽

10.2174/2212797613999201231200939 ◽

2020 ◽

Vol 13 ◽

Author(s):

Xintian Liu ◽

Yang Qu ◽

Xiaobing Yang ◽

Yongfeng Shen

Keyword(s):

Fatigue Life ◽

High Speed ◽

Two Dimensional ◽

Load Spectrum ◽

One Dimensional ◽

Life Estimation ◽

Load Spectra ◽

Fatigue Life Estimation ◽

Program Load Spectrum ◽

Program Load

Background:: In the process of high-speed driving, the wheel hub is constantly subjected to the impact load from the ground. Therefore, it is important to estimate the fatigue life of the hub in the design and production process. Objective:: This paper introduces a method to study the fatigue life of car hub based on the road load collected from test site. Methods:: Based on interval analysis, the distribution characteristics of load spectrum are analyzed. The fatigue life estimation of one - dimensional and two - dimensional load spectra is compared by compiling load spectra. Results:: According to the S-N curve cluster and the one-dimensional program load spectrum, the estimated range fatigue life of the hub is 397,100 km to 529,700 km. For unsymmetrical cyclic loading, each level means and amplitude of load were obtained through the Goodman fatigue empirical formula, and then according to S-N curve clusters in the upper and lower curves and two-dimensional program load spectrum, estimates the fatigue life of wheel hub of the interval is 329900 km to 435200 km, than one-dimensional load spectrum fatigue life was reduced by 16.9% - 17.8%. Conclusion:: This paper lays a foundation for the prediction of fatigue life and the bench test of fatigue durability of auto parts subjected to complex and variable random loads. At the same time, the research method can also be used to estimate the fatigue life of other bearing parts or high-speed moving parts and assemblies.

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Improved numerical model for fatigue cumulative damage of mechanical structure considering load sequence and interaction

Advances in Mechanical Engineering ◽

10.1177/1687814021995309 ◽

2021 ◽

Vol 13 (2) ◽

pp. 168781402199530

Author(s):

Bixiong Huang ◽

Shuci Wang ◽

Shuanglong Geng ◽

Xintian Liu

Keyword(s):

Fatigue Life ◽

Theoretical Basis ◽

Life Prediction ◽

Damage Model ◽

Cumulative Damage ◽

Load Spectrum ◽

Random Load ◽

Mechanical Parts ◽

Proposed Model ◽

Load Sequence

To more accurately predict the fatigue life of components under the action of random loads, it is necessary to explore the influence of the interaction between the load sequence and the load on the life prediction. Based on the Manson-Halford method and Corten-Dolan model, this paper establishes a fatigue cumulative damage model that takes into account both the load order and the interaction between loads, and also takes into account the loads near the fatigue limit. The fatigue life of mechanical parts under random load can be calculated through this model, which provides a theoretical basis for life prediction under random load spectrum. The fatigue life of mechanical parts under random load can be calculated through this model, which provides a theoretical basis for life prediction under random load spectrum. Comparing the calculation results of the proposed model with the results of Palmgren Miner, Manson-Halford method, and Corten-Dolan model, it is found that the fatigue damage model established can reasonably predict the fatigue life of parts. Comparison and verification of examples further prove the accuracy and reliability of the proposed model.

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Processing Load Signal on Wheel Loader Transmission

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.383-390.4482 ◽

2011 ◽

Vol 383-390 ◽

pp. 4482-4485

Author(s):

Li Sun ◽

Yong Chen Liu

Keyword(s):

Time Course ◽

Load Spectrum ◽

Processing Load ◽

Random Load ◽

Pass Filter ◽

Low Pass Filter ◽

Wheel Loader ◽

Virtual Test ◽

Low Pass ◽

Filter Frequency

To determine fatigue life of Loader transmission and to analyze machine power for different user, the torque loads of wheel loader transmission are tested and calibrated with the method of four sections per cycle. The disturbed signals are filtered by low-passed filter, and anomalous spikes are eliminated with the NSOFT. And contrastively analyzes the disposal effect of signal, then acquires pure random load-time course. It concludes that one Hz of the low-pass filter frequency is suitable, and the test signal is in line with the actual work of Loader. These provide the base for getting load spectrum and virtual test on wheel loader transmission.

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