Non-Relaxing Crack Growth and Fatigue in a Non-Crystallizing Rubber

1974 ◽  
Vol 47 (5) ◽  
pp. 1253-1264 ◽  
Author(s):  
P. B. Lindley
Keyword(s):  
Crack Growth ◽  
Growth Behavior ◽  
Crack Growth Behavior ◽  
Maximum Deformation ◽  
Fatigue Data ◽  
Tentative Explanation ◽  
Tearing Energy ◽  
Relationship Of ◽  
The Relationship ◽  
Unique Relationship

Abstract The crack growth behavior of a non-crystallizing rubber, SBR, is investigated in terms of the tearing energy T, the energy available for crack growth. For cyclic deformations in which the minimum tearing energy is zero (relaxing conditions), a unique relationship is obtained between the growth per cycle and T at the maximum deformation. This rubber also exhibits crack growth at constant tearing energies. The relationship of the crack growth rate as a function of tearing energy, when the minimum tearing energy of the cycle is not zero, can be superimposed on the relaxing relationship by scaling the rates, and a tentative explanation is proposed for the scaling factor. Fatigue data are consistent with this.

Contributions of Time Dependent and Cyclic Crack Growth to the Crack Growth Behavior of Non Strain-Crystallizing Elastomers

2002 ◽  
Vol 75 (4) ◽  
pp. 643-656 ◽  
Author(s):  
J. J. C. Busfield ◽  
K. Tsunoda ◽  
C. K. L. Davies ◽  
A. G. Thomas
Keyword(s):  
Crack Growth ◽  
Growth Behavior ◽  
Time Dependent ◽  
Crack Growth Behavior ◽  
Wide Range ◽  
Dependent Component ◽  
Tearing Energy ◽  
Quasi Crystals ◽  
Crack Growth Rates ◽  
Time Dependent Crack Growth

Abstract Engineering components are observed to fail more rapidly under cyclic loading than under static loading. This reflects features of the underlying crack growth behavior. This behavior is characterized by the relation between the tearing energy, T, and the crack growth per cycle, dc/dn. The increment of crack growth during each cycle is shown here to result from the sum of time dependent and cyclic crack growth components. The time dependent component represents the crack growth behavior that would be present in a conventional constant T crack growth test. Under repeated stressing additional crack growth, termed the cyclic crack growth component, occurs. For a non-crystallizing elastomer, significant effects of frequency have been found on the cyclic crack growth behavior, reflecting the presence of this cyclic element of crack growth. The cyclic crack growth behavior over a wide range of frequencies was investigated for unfilled and swollen SBR materials. The time dependent crack growth component was calculated from constant T crack growth tests and the cyclic contribution derived from comparison with the observed cyclic growth. It is shown that decreasing the frequency or increasing the maximum tearing energy during a cycle results in the cyclic crack growth behavior being dominated by time dependent crack growth. Conversely at high frequency and at low tearing energy, cyclic crack growth is dominated by the cyclic crack growth component. A large effect of frequency on cyclic crack growth behavior was observed for highly swollen SBR. The cyclic crack growth behavior was dominated by the time dependent crack growth component over the entire range of tearing energy and/or crack growth rate. The origin of the cyclic component may be the formation/melting of quasi crystals at the crack tip, which is absent at fast crack growth rates in the unswollen SBR and is absent at all rates in the swollen SBR.

Crack Growth Characteristics of Pure Copper for Smart Stress Memory Patch

2007 ◽  
Vol 353-358 ◽  
pp. 2045-2048
Author(s):  
Shoichi Nambu ◽  
Manabu Enoki
Keyword(s):  
Crack Propagation ◽  
Crack Length ◽  
Crack Growth ◽  
Stress Amplitude ◽  
Pure Copper ◽  
Growth Behavior ◽  
Growth Characteristics ◽  
Crack Growth Behavior ◽  
Stress Memory ◽  
The Relationship

A new sensing method called “smart stress memory patch”, which could estimate the maximum stress, the stress amplitude and the fatigue cyclic number simultaneously using Kaiser effect of Acoustic Emission (AE) and crack length of this patch, was developed. In this study, the crack growth characteristics of this patch was evaluated. Pure copper was used for this patch because its good corrosion resistance, stable crack propagation and so on. Two kinds of samples which were rolled and electrodeposited copper were prepared to investigate the effect of microstructure on crack growth behavior. Fatigue test was performed under constant stress amplitude to evaluate the crack growth behavior using the relationship between stress intensity factor range and crack propagation rate. The scattering in fatigue crack growth was also investigated to obtain the relationship between crack length and the fatigue cyclic number including two-sided 95% confidence interval. The effect of thickness and grain size on the scattering was discussed. Finally, good crack growth behavior was obtained and the fatigue cyclic number could be estimated by this patch.

FATIGUE BEHAVIOR AND THE RELATIONSHIP BETWEEN CRACK PROPAGATION AND THE SLIT CONFIGURATION OF C/C COMPOSITES

2013 ◽  
Vol 27 (13) ◽  
pp. 1350094 ◽  
Author(s):  
MD. SHAFIUL FERDOUS ◽  
SOFYAN ARIEF SETYABUDI ◽  
CHOBIN MAKABE ◽  
MASAKI FUJIKAWA
Keyword(s):  
Fatigue Strength ◽  
Crack Growth ◽  
Fracture Behavior ◽  
Maximum Stress ◽  
Fatigue Behavior ◽  
Growth Behavior ◽  
Crack Growth Behavior ◽  
Fatigue And Fracture ◽  
Slit Length ◽  
The Relationship

The fatigue and fracture behavior of C/C composites fabricated using fine-woven carbon fiber laminates with α = 0/90° direction were investigated. Also, the phenomenon of crack growth behavior and the shear damage in the fiber bundle was discussed. Slits of several sizes were cut on both sides of a test section and different sizes of slit length were chosen. The effect of the slit configuration on crack initiation and growth behavior was observed. Specimens with blunt-notches and center-holes were also used to compare the fatigue strength and crack growth behavior. Non-propagating cracks were observed and fatigue limit was defined as the maximum stress at which specimen did not break for N = 107 cycles stress application. The longest fatigue life was obtained in the case of specimens with shorter slits. The relationships between fatigue strengths and specimen shapes were analyzed by stress concentration, K t , and stress intensity factor, K I . The effect of slit configuration on fatigue strength was then discussed regarding both the experimental and calculated consequences.

Effect of Creep Holding Time on the Fatigue Behavior in P92 Steel Weldment at High Temperature

2005 ◽  
Vol 475-479 ◽  
pp. 4211-4214 ◽  
Author(s):  
Bum Joon Kim ◽  
Byeong Soo Lim
Keyword(s):  
Growth Rate ◽  
High Temperature ◽  
Crack Growth ◽  
Fatigue Behavior ◽  
Growth Behavior ◽  
Holding Time ◽  
Crack Growth Behavior ◽  
Wave Shape ◽  
P92 Steel ◽  
The Relationship

In this study, the crack growth behavior in P92 steel (9%Cr-2%W) weldment was investigated at 600ı under the load of trapezoidal wave shape with various holding times. The relationship between the crack growth behavior and holding time was studied and it was characterized using the ΔK and (Ct)avg parameters. The number of micro-voids/cavities at the crack tip and fracture modes were examined and the relationship between crack growth rate and holding time was investigated.

Dwell-fatigue crack growth mechanisms of titanium alloy Ti-6Al-4V at room-temperature

2019 ◽  
Vol 34 (01n03) ◽  
pp. 2040033
Author(s):  
Ke Wang ◽  
Xiaopeng Sun ◽  
Yongzheng Li ◽  
Pengyu Wei ◽  
Jiarui Liu ◽  
...  
Keyword(s):  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Dwell Time ◽  
Growth Behavior ◽  
Crack Growth Behavior ◽  
Fatigue Crack Growth Behavior ◽  
Dwell Fatigue ◽  
Manned Submersible ◽  
The Relationship

Ti-6Al-4V alloy is widely used for the deep-sea manned submersible. In addition to the normal cyclic loading, the manned cabin will experience a period of dwell time in each cycle during their service life. In this research, the fatigue and dwell-fatigue crack growth behavior of Ti-6Al-4V alloy under different dwell time were studied experimentally. The mechanism of dwell-fatigue crack growth was investigated. The acceleration phenomenon of the dwell-fatigue crack growth can be directly observed in the experiment. The relationship between the crack length and the dwell time was captured under different [Formula: see text] within one cycle. The results presented that there is a saturation time for the dwell-fatigue crack growth. A prediction model is proposed to predict the dwell-fatigue crack growth behavior considering the effects of dwell time.

A Study on the Relationship between Fatigue Crack Growth Behavior and Cyclic Crack Tip Opening Displacement

2006 ◽  
Vol 326-328 ◽  
pp. 1051-1054 ◽  
Author(s):  
Hyeon Chang Choi ◽  
Hyeon Ki Choi
Keyword(s):  
Fatigue Crack ◽  
Crack Growth ◽  
Crack Tip ◽  
Growth Behavior ◽  
Crack Growth Behavior ◽  
Fatigue Crack Growth Behavior ◽  
Crack Tip Opening Displacement ◽  
Opening Displacement ◽  
Crack Tip Opening ◽  
The Relationship

The relationship between fatigue crack growth behavior and cyclic crack tip opening displacement is studied. An elastic-plastic finite element analysis (FEA) is performed to examine the growth behavior of fatigue crack, where the contact elements are used in the mesh of the crack tip area. We investigate the relationship between the reversed plastic zone size and the changes of the cyclic crack tip opening displacement along the crack growth. The cyclic crack tip opening displacement is related to fatigue crack opening behavior.

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