Crack propagation in elastomers subjected to cyclic loading

2019 ◽  
Vol 233 (11) ◽  
pp. 2301-2310
Author(s):  
Adel Hamdi ◽  
Abdelkader Boulenouar ◽  
Noureddine Benseddiq ◽  
Sofiane Guessasma
Keyword(s):  
Growth Rate ◽  
Cyclic Loading ◽  
Crack Growth Rate ◽  
Crack Propagation ◽  
Crack Growth ◽  
Shear Loading ◽  
Styrene Butadiene Rubber ◽  
Butadiene Rubber ◽  
Fracture Surfaces ◽  
Styrene Butadiene

This work tackles crack propagation mechanisms of styrene butadiene and natural rubbers, both subject to cyclic loading under a positive load ratio. The experimental evidence is based on pure shear loading of notched specimens supported by SEM analysis of fracture surfaces. Relationship between crack growth rate and tearing energy is revisited. The experimental results show that the fatigue behaviour of studied vulcanisates can be clearly separated in the power-law regime. Furthermore, the reported results from the literature extend this statement to any load condition. Fracture surface observations reveal also differences in energy dissipation mechanisms inferred to structural mutations in the case of natural rubber. Alternation of rough and smooth fracture surfaces associated with change in crack growth rate is more likely to occur for styrene butadiene rubber. All observations suggest that crack branching is a secondary ranked dissipation mechanism for the studied materials compared to crack deviation.

Effect of Cyclic Loading on Crack Propagation of X-70 Pipeline Steel in Near-Neutral pH Solution

2005 ◽  
Vol 297-300 ◽  
pp. 2501-2507 ◽  
Author(s):  
Hao Guo ◽  
Guang Fu Li ◽  
Xun Cai ◽  
Jiasheng Bai ◽  
Wu Yang
Keyword(s):  
Growth Rate ◽  
Cyclic Loading ◽  
Crack Growth Rate ◽  
Tensile Stress ◽  
Crack Propagation ◽  
Crack Growth ◽  
Pipeline Steel ◽  
Stress Axis ◽  
Mode I ◽  
Propagation Period

Crack propagation of X-70 pipeline steel in near-neutral pH solution was studied under different modes of cyclic loading. A revised equation of crack growth rate vs. Δ K was obtained. Average crack growth rate increased with cycles under conditions of different R values. Linear shape notch specimen made cracks much easier to initiate and propagate than V-shaped notch specimen did. For different R values, the curves of crack growth rate with cycles were similar, but the platform propagation period and quick propagation period were different obviously. Crack growth rate at both periods increased and thus failure time decreased markedly with decrease of R value. The propagation directions of cracks were different under different cyclic loading conditions. Under mode I (single tensile stress) cyclic loading, cracks were straight and perpendicular to the tensile stress axis, while under mixed-mode I/III (tensile/shear stress) cyclic loading, cracks were sinuous and did not propagate in the direction perpendicular to the main tensile stress axis.

Prestrain Influence on Fatigue Crack Propagation in a 304L Stainless Steel

2009 ◽  
Author(s):  
Kokleang Vor ◽  
Catherine Gardin ◽  
Christine Sarrazin-Baudoux ◽  
Jean Petit ◽  
Claude Amzallag
Keyword(s):  
Growth Rate ◽  
Stainless Steel ◽  
Fatigue Crack ◽  
Crack Growth Rate ◽  
Crack Propagation ◽  
Crack Growth ◽  
Fatigue Crack Propagation ◽  
Crack Closure ◽  
Threshold Region ◽  
304L Stainless Steel

The scope of this study is to investigate the effect of tensile prestrain on crack growth behavior in a 304L stainless steel. Fatigue crack propagation tests were performed on single-edge notched tension (SENT) raw specimens (0% of prestrain) and on prestrained specimens (2% and 10%). On one hand, it is found that the different levels of prestrain exhibit no significant influence on crack propagation in the high range of Stress Intensity Factor (SIF), where there is no detectable crack closure. On the other hand, a clear effect of prestrain on crack growth rate can be observed in the near threshold region where closure is detected. Thus, it can be concluded that the prestrain mainly affects the crack growth rate through its influence on the crack closure.

CROSSLINKING OF SBR COMPOUNDS FOR TIRE TREAD USING BENZOCYCLOBUTENE CHEMISTRY

2019 ◽  
Vol 92 (1) ◽  
pp. 25-42 ◽  
Author(s):  
Akshata Kulkarni ◽  
Coleen Pugh ◽  
Sadhan C. Jana ◽  
Darnell T. Wims ◽  
Ammar Abdel Gawad
Keyword(s):  
Crack Growth ◽  
Abrasion Resistance ◽  
Crack Growth Resistance ◽  
Styrene Butadiene Rubber ◽  
Butadiene Rubber ◽  
Self Healing ◽  
Styrene Butadiene

ABSTRACT This research investigates the potential of benzocyclobutene (BCB) chemistry for crosslinking styrene-butadiene rubber in conjunction with sulfur curatives with the objective of achieving curing at lower temperatures and/or in shorter times compared with entirely sulfur-based cure formulations. The reversible polysulfidic linkages produced in sulfur crosslinking allow self-healing characteristics but suffer from poor heat-aging stability. The C–C crosslinks from BCB chemistry are irreversible and offer higher resistance to aging, but they do not present apparent self-healing properties. The hybrid curative package based on C–C, C–S, and S–S linkages developed is expected to provide reduced crosslinking time and/or temperature, along with higher crack-growth resistance, the ability to self-heal, higher resistance to fatigue-to-failure, reduced hysteresis, and increased abrasion resistance. The crosslinking performance of 1-substituted BCB-based compounds in conjunction with sulfur is specifically investigated.

COMPARISON OF SINE VERSUS PULSE WAVEFORM EFFECTS ON FATIGUE CRACK GROWTH BEHAVIOR OF NR, SBR, AND BR COMPOUNDS

2010 ◽  
Vol 83 (4) ◽  
pp. 391-403 ◽  
Author(s):  
G. Andreini ◽  
P. Straffi ◽  
S. Cotugno ◽  
G. Gallone ◽  
G. Polacco
Keyword(s):  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Natural Rubber ◽  
Crack Growth ◽  
Fine Tuning ◽  
Styrene Butadiene Rubber ◽  
Butadiene Rubber ◽  
Pulse Waveform ◽  
Tearing Energy ◽  
Styrene Butadiene

Abstract Fatigue crack growth experiments on carbon black-filled rubber compounds have been carried out to evaluate the influence of testing conditions over different compound formulations. Investigations on the influence of waveform, data acquisition, and compound formulation have been performed on strip-tensile specimens reproducing the mode I of crack opening. The response of three different compound formulations (based on either natural rubber, butadiene rubber, or styrene-butadiene rubber) to the application of two different waveforms, pulse and sine, has been analyzed, showing significant differences in fatigue behavior and ranking of the various compounds. Compared to the sinusoidal waveform, the use of a pulse waveform provided an improved correlation of the tearing energy with the crack propagation speed. This difference was particularly evident in the case of natural rubber and butadiene rubber, while it resulted negligible in the case of styrene-butadiene rubber. Such a different behavior could be attributed to differences in macromolecular chains orientation. Fine-tuning of video acquisition parameters provided an accurate observation of the crack growth process, as confirmed by the low standard deviation of the estimated tearing energy and crack growth rate.

Effect of Environment on Fatigue Crack Propagation Behavior of an Al-Cu-Mg Aluminum Alloy

2014 ◽  
Vol 1004-1005 ◽  
pp. 142-147
Author(s):  
Ming Liu ◽  
Kun Zhang ◽  
Sheng Long Dai ◽  
Guo Ai Li ◽  
Min Hao ◽  
...  
Keyword(s):  
Growth Rate ◽  
Fatigue Crack ◽  
Crack Growth Rate ◽  
Fatigue Crack Growth ◽  
Crack Propagation ◽  
Crack Growth ◽  
Fatigue Crack Propagation ◽  
Fatigue Crack Growth Rate ◽  
Fatigue Crack Propagation Behavior ◽  
Stress Ratios

The fatigue crack propagation behaviors of an Al-Cu-Mg alloy are investigated in different environments and with varying stress ratios. Fatigue experiments are carried out via a fatigue crack growth rate test in laboratory air, a 3.5% (mass fraction) NaCl solution and a tank seeper. The results show that a corrosion environment has an obvious influence on the fatigue crack growth rate, and the degrees of influence of the two different corrosive environments are basically identical. When the stress ratio is R = 0.5 and 0.06 with a decrease of the stress intensity factor, the difference in the crack propagation rates for the corrosion and air environments gradually increases. However, the corrosion acceleration in each stage of crack propagation is obvious while R=−1.

New insight into the flocculation behavior of hydrophilic silica in styrene butadiene rubber composites

RSC Advances ◽  
2015 ◽  
Vol 5 (111) ◽  
pp. 91262-91272 ◽  
Author(s):  
Juqiao Su ◽  
Qi Yang ◽  
Dahang Tang ◽  
Yajiang Huang ◽  
Zhongguo Zhao ◽  
...  
Keyword(s):  
Crack Growth ◽  
Crack Tip ◽  
Styrene Butadiene Rubber ◽  
Butadiene Rubber ◽  
Rubber Composites ◽  
Modified Silica ◽  
Filled Rubber ◽  
Styrene Butadiene ◽  
Insight Into

We propose that modified silica filled rubber composites with moderate silica flocculation possesses preferable resistance to crack growth by the crack tip deflection mechanism.

Fatigue Crack Growth Rate of Reeled Pipe in Sour Environments

2015 ◽  
Author(s):  
Javad Safari ◽  
Ramgopal Thodla ◽  
Ian Merchant ◽  
John Hamilton
Keyword(s):  
Growth Rate ◽  
Fatigue Crack ◽  
Cyclic Loading ◽  
Crack Growth Rate ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Fatigue Crack Growth Rate ◽  
Paris Law ◽  
Number Of Cycles ◽  
Corrosive Environments

Fatigue Crack Growth Rate (FCGR) of reeled pipe (strained & aged) in sour environments was investigated. FCGR frequency scans on different microstructures, i.e. heat affected zone (HAZ), and weld center line (WCL), revealed that, FCGR in corrosive environments increased with decreasing frequency and reached a plateau value at low frequencies of 10mHz to 3mHz. At these ‘plateau frequencies’, FCGR in the moderately sour environment that was investigated were found to be about 10–18× or 30× higher than the in-air values for the WCL and HAZ, respectively. There was no effect of the reeling cycles on the FCGR of the WCL or HAZ specimens. The FCGRs of the WCL were consistently lower than that of the HAZ by about a factor of 2–3× under various conditions. The reason for the lower FCGR of the WCL is not well understood. It is possible that it may be due to the higher yield strength (YS) of the overmatched welds, differing hydrogen concentration and/or diffusion coefficient or possibly due to the differences in the microstructure between the HAZ and WCL. Paris law curves, FCGRs as a function of ΔK (stress intensity factor range), were measured on the HAZ, and WCL (both intrados) at the plateau frequency (10mHz), representative of flowline cyclic loading. They were also measured at a higher frequency of 0.33Hz, representative of Steel Catenary Risers (SCR) cyclic loading associated with wave motion. Comparisons of measured Paris law curves in corrosive environments to those in air were consistent with the results of the frequency scans. There was no effect of number of cycles of reeling on the Paris law curves in the sour environment tested for WCL and HAZ specimens at both the plateau frequency and 0.33Hz. The results of the test program suggest FCGR of WCL and HAZ in the sour environment tested are not affected by number of cycles (up to 5) of straining on the intrados side for the strain level (1.93% per cycle) used in this study.

Sign in / Sign up

Export Citation Format

Share Document