scholarly journals Characterization and Quantitative Analysis of Crack Precursor Size for Rubber Composites

Materials ◽  
2019 ◽  
Vol 12 (20) ◽  
pp. 3442 ◽  
Author(s):  
Hao Guo ◽  
Fanzhu Li ◽  
Shipeng Wen ◽  
Haibo Yang ◽  
Liqun Zhang
Keyword(s):  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Fatigue Failure ◽  
Theoretical Formula ◽  
Uniaxial Tensile ◽  
Rubber Composites ◽  
Economic Output ◽  
Average Size ◽  
Crack Growth Model

In the field of engineering, the annual economic loss caused by material fatigue failure reaches 4% of the total economic output. The deep understanding of rubber fatigue failure can help develop and prepare rubber composites with high durability. The crack precursor sizes within the rubber composites are vital for the material mechanical and fatigue properties. In this study, we adopted three different characterization methods to analyze crack precursor sizes and their distribution. First, based on the theoretical formula of fracture mechanics, the size of the crack precursor was deduced from 180 μm to 500 μm by the uniaxial tensile experiment combined with tear test (nicked angle tear, planar tear and trouser tear). Second, by combining the uniaxial fatigue test of dumbbell specimen with the fatigue crack growth rate test, the average size of the crack precursor was calculated as 3.3 μm based on the Thomas fatigue crack growth model. Third, the average size of the crack precursor was 3.6 μm obtained by scanning electron microscope. Through theoretical calculations and experimental tests, the size and distribution of the crack precursors of rubber composites were systematically presented. This work can provide theoretical guidance for the improvement of fatigue performance of rubber composites.

A uniaxial tensile behavior based fatigue crack growth model

2020 ◽  
Vol 131 ◽  
pp. 105324 ◽  
Author(s):  
S.C. Wu ◽  
C.H. Li ◽  
Y. Luo ◽  
H.O. Zhang ◽  
G.Z. Kang
Keyword(s):  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Growth Model ◽  
Tensile Behavior ◽  
Uniaxial Tensile ◽  
Behavior Based ◽  
Crack Growth Model

Two-parameter mechanistic model for the fatigue crack growth of metals

2019 ◽  
Vol 12 (2) ◽  
Author(s):  
Tawqeer Zada
Keyword(s):  
Experimental Data ◽  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Fatigue Failure ◽  
Mechanistic Model ◽  
Model Development ◽  
Two Parameters ◽  
Crack Growth Model ◽  
Two Parameter

In this paper, a two-parameter mechanistic model for the fatigue crack growth has been developed. Fatigue failure is the major causes of mechanical structural failure. The fatigue failure progress in three stages crack initiation, crack growth and final failure. The fatigue crack growth has been modelled by different approaches, however these approaches are generally empirical. In this paper, a mechanistic fatigue crack growth model is proposed. The striation and its relation to the cyclic load is used for the model development. Scanning electronic microscope results are used to establish relation between striation and crack growth. The developed model is two-parameters. The model has been implemented and validated using experimental data from the literature. The model prediction is satisfactory in region II of the crack growth curve. However, in region I and region III the model deviates from experimental data. It is suggested to incorporate interaction of monotonic and cyclic loading in the mechanistic modelling for the fatigue growth.

Evaluation of Fatigue Crack Growth Curves in Existing Codes and a Proposed Modification Based on Experimental Data of Cr-Ni-Mo-V Steel Welded Joints

2016 ◽  
Author(s):  
Yan-Nan Du ◽  
Ming-Liang Zhu ◽  
Fu-Zhen Xuan ◽  
Shan-Tung Tu
Keyword(s):  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Welded Joints ◽  
Growth Curves ◽  
Crack Growth Behavior ◽  
Fatigue Assessment ◽  
Crack Growth Model ◽  
Threshold Regime ◽  
Near Threshold

A comparison of currently available codes for assessment of fatigue crack growth, including ASME (America Society of Mechanical Engineers) SEC. XI, FKM (Forchungskuratorium Maschinenbau) guideline, WES (Japan Welding Engineering Society) 2805, BS7910 and JSME (The Japan Society of Mechanical Engineers), was carried out by paying attention to the suitability of application and the easiness to obtain the parameters, based on fatigue crack growth data of Cr-Ni-Mo-V steel welded joints. Results showed that fatigue crack growth curves provided by the FKM or WES were good choice when few inputs were at hand while the curves in the BS7910, JSME and ASME were recommended for precise estimation. It was indicated that the assessment of welded joints solely by fatigue crack growth behavior at base metal part and the assessment of fatigue crack growth for the aged condition by as-received one both resulted in non-conservativeness, albeit dependent on the range of stress ratios, R. A new bilinear form of fatigue crack growth model independent of R was developed based on transition point occurred in the near-threshold regime. This constituted the bilinear approach to fatigue assessment, and thus contributed to the optimization of fatigue assessment in the near-threshold regime.

Fatigue

2020 ◽  
pp. 529-546
Author(s):  
Lallit Anand ◽  
Sanjay Govindjee
Keyword(s):  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Failure Analysis ◽  
Crack Growth ◽  
Fatigue Failure ◽  
Miner’S Rule ◽  
Miner's Rule ◽  
Repeated Loads

This chapter introduces methods for analysing fatigue failure of materials under repeated loads. The notions of defect-free and defect-tolerant failure analysis are discussed. For defect free analysis the notion of S-N curves is introduced and Coffin-Mason low cycle as well as Basquin high cycle relations are discussed. Miner’s rule is also introduced. For a defect-tolerant approach Paris’s law for fatigue crack growth is presented.

Fatigue Life Prediction Based on Probabilistic Fracture Mechanics: Case Study of Automotive Parts

2015 ◽  
Vol 2 (1) ◽  
Author(s):  
Mahboubeh Yazdanipour ◽  
Mohammad Pourgol-Mohammad ◽  
Naghd-Ali Choupani ◽  
Mojtaba Yazdani
Keyword(s):  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Fracture Mechanics ◽  
Crack Growth ◽  
Probabilistic Models ◽  
Fatigue Loading ◽  
Critical Fields ◽  
Propagation Of Uncertainty ◽  
Automotive Parts ◽  
Crack Growth Model

This paper studies the stochastic behavior of fatigue crack growth analytically and empirically by employing basic models in fracture mechanics. The research estimates the crack growth rate probabilistically, quantifies the uncertainty of probabilistic models under fatigue loading in automotive parts, and applies the simulations on W319 aluminum alloy, which has vast applications in automotive components’ products. Walker and Forman correlations are used in the paper. The deterministic simulations of these models are verified with afgrow code and validated experimentally with fatigue data of W319 aluminum. Then, the models are treated probabilistically by considering the models’ parameters stochastic. Monte Carlo (MC) simulation is employed to investigate the models under stochastic conditions. The paper is quantifies the propagation of uncertainty with calculating the standard deviations of crack lengths via cycles. The proposed procedure is useful for selecting a proper probabilistic fatigue crack growth model in specific applications and can be used in future fatigue studies not only in the automotive industry but also in other critical fields, to obtain more reliable conclusions.

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