Mixing time influence on fatigue crack growth in a carbon black-filled natural rubber vulcanizate

2019 ◽  
Vol 36 (2) ◽  
pp. 115-130
Author(s):  
Harini Sridharan ◽  
Jagannath Chanda ◽  
Prasenjit Ghosh ◽  
Rabindra Mukhopadhyay
Keyword(s):  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Carbon Black ◽  
Crack Growth ◽  
Mixing Time ◽  
Processing Parameters ◽  
Rubber Matrix ◽  
Mixing Times ◽  
Bound Rubber ◽  
The Difference

Various processing parameters affect the dispersion of carbon black (CB) in a rubber matrix, of which mixing time plays a major role. The physical properties of a green compound namely bound rubber and Mooney viscosity along with mechanical and fatigue crack growth (FCG) are affected by the dispersion of filler particles. To determine the effect of mastication on dispersion, the mixing time was varied from 120 s to 600 s where it was gauged that an optimum range of mixing times display better dispersion. The difference in dispersion between the green and the cured compounds was also stark due to the flocculation mechanism. Longer mixing times do not show much decrease in agglomerate size on curing, that is, approximately 2%, whereas shorter time has led to a decrease of 20%. The FCG properties were studied using a tear and fatigue analyser, where the FCG rate displays a similar trend with the dispersion of CB.

scholarly journals Effect of Temperature on the Tear Fracture and Fatigue Life of Carbon-Black-Filled Rubber

Polymers ◽  
2019 ◽  
Vol 11 (5) ◽  
pp. 768 ◽  
Author(s):  
Wenbo Luo ◽  
Ming Li ◽  
Youjian Huang ◽  
Boyuan Yin ◽  
Xiaoling Hu
Keyword(s):  
Fatigue Crack ◽  
Fatigue Life ◽  
Fatigue Crack Growth ◽  
Carbon Black ◽  
Crack Growth ◽  
Effect Of Temperature ◽  
Temperature Dependent ◽  
Fatigue Crack Propagation Behavior ◽  
Filled Rubber ◽  
Different Temperatures

The mechanical behaviour of carbon-black (CB)-filled rubber is temperature-dependent. It is assumed that temperature affects the fatigue life of rubber products by changing the tear energy of the material. The static tearing behaviour and fatigue crack propagation behavior of CB-filled rubber at different temperatures were investigated in this study. The critical tear energy of the material was measured through static tear fracture tests at different temperatures; it is shown that the critical tear energy decreases exponentially with increasing temperature. A fatigue crack growth test of a constrained precracked planar tension specimen was conducted at room temperature; the measurements verify that the fatigue crack growth follows a Paris–Erdogan power law. Considering the temperature dependence of the critical tear energy, the temperature dependent fatigue crack growth kinetics of CB-filled rubber was established, and the fatigue life of the material at high temperatures was predicted based on the kinetics. The predictions are in good agreement with experimental measurements.

scholarly journals Mechanism of Fatigue Crack Growth in Carbon Black Filled Natural Rubber

2004 ◽  
Vol 37 (13) ◽  
pp. 5011-5017 ◽  
Author(s):  
J.-B. Le Cam ◽  
B. Huneau ◽  
E. Verron ◽  
L. Gornet
Keyword(s):  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Carbon Black ◽  
Natural Rubber ◽  
Crack Growth

scholarly journals FATIGUE CRACK GROWTH BEHAVOR OF CARBON BLACK–REINFORCED NATURAL RUBBER

2021 ◽  
Author(s):  
Lewis B. Tunnicliffe
Keyword(s):  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Carbon Black ◽  
Natural Rubber ◽  
Crack Growth ◽  
Crack Tip ◽  
Growth Behavior ◽  
Crack Growth Behavior ◽  
Fatigue Crack Growth Behavior ◽  
Amplification Factors

ABSTRACT Fatigue crack growth behavior of carbon black–reinforced natural rubber is investigated. Rubber compounds of Shore A = 70 are prepared by varying the formulation loadings of a wide range of carbon black types based on their structure and surface area properties. The resulting fatigue crack growth behavior shows significant variation in β exponent values, depending on the properties of the carbon black. These variations are rationalized by considering the strain amplification of natural rubber by carbon black aggregates in the region of compound directly ahead of the crack tip. An assumption is made that little networking of the carbon black aggregates exists in this region of very high strain and that hydrodynamic calculations that consider occluded rubber can therefore provide realistic values for strain amplification. A reasonable scaling of power law crack growth parameters to calculated strain amplification factors is found, with the exponent, β, decreasing with increasing strain amplification. The implication here is that enhanced strain amplification promotes the formation of strain-induced crystallites in the crack tip region. Performance tradeoffs resulting from the crossover of crack growth data sets dependent on the carbon black type are discussed. Of practical significance is the fact that the strain amplification factors can be calculated directly from knowledge of carbon black type and loading in rubber formulations.

Fatigue Crack Growth and Threshold Behavior of DMLS Ti6Al4V

2017 ◽  
Vol 267 ◽  
pp. 157-161
Author(s):  
Radomila Konečná ◽  
Ludvík Kunz ◽  
Pavel Pokorný ◽  
Gianni Nicoletto
Keyword(s):  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Propagation ◽  
Crack Growth ◽  
Fatigue Cracks ◽  
Processing Parameters ◽  
Crack Growth Behavior ◽  
Threshold Values ◽  
Stress Relieving ◽  
Crack Growth Curve

Growth of long fatigue cracks in Ti6Al4V alloy manufactured by direct metal laser sintering (DMLS) was investigated. Two DMLS systems, EOSINT M270 and EOSINT M290, with different process parameters were used for production of CT specimens having three different orientations of crack propagation with respect to the DMLS build direction. The as-built specimens were stress relieved at 740 °C. The fatigue crack growth curve and the threshold values of the stress intensity factor for crack propagation were experimentally determined. It has been found that the chosen DMLS processing parameters and the used stress relieving procedure results in material exhibiting isotropic crack growth behavior, i.e. the crack growth was found to be independent of the DMLS build direction. The fatigue crack growth rates and the threshold values for the crack growth were compared with published results characterizing the as-built material and material after different post processing heat treatments.

Fatigue Crack Growth and Precipitation Characteristics of a High Zn-Containing Al-Zn-Mg-Cu Alloy with Various Typical Aging States

2021 ◽  
Vol 1026 ◽  
pp. 19-27
Author(s):  
Kai Wen ◽  
Hong Wei Liu
Keyword(s):  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Fracture Morphology ◽  
Precipitate Size ◽  
Fatigue Crack Growth Resistance ◽  
Cu Alloy ◽  
Precipitation Characteristics ◽  
The Matrix ◽  
The Difference

The fatigue crack growth of Al-Zn-Mg-Cu alloy can be adjusted by different aging treatments. In the present work, a high Zn-containing Al-Zn-Mg-Cu alloy was treated by single, double and triple stage aging treatments and typical T6, T79 and T77 states were selected by tensile properties. Fatigue crack growth under these aging states was tested and related fracture morphology and precipitation characteristics were observed. The results showed that fatigue crack growth resistance for the alloy was T6<T79<T77. The corresponding fracture morphology also showed the difference of fatigue striations and the measurement of them provided an additional evidence. The precipitation proved that the alloy with T6 state possessed GPI zone, GPII zone and η' phase while that for T76 state was GPII zone, η' phase and η phase. As for the T77 state, the precipitate types were GPII zone and η' phase. The matrix precipitate for T6 state was smaller and denser than that for T79 and T77 states while that for T77 state possessed a dense distribution than that for T79 state. The measurement of precipitate size distribution also proved it. The grain boundary precipitates for T79 and T77 states were similar, which had a more intermittent distribution than that for T6 state.

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