Creep Failure of Rat Tail Tendon

1978 ◽  
Vol 100 (4) ◽  
pp. 229-234 ◽  
Author(s):  
D. G. Ellis
Keyword(s):  
Activation Energy ◽  
Failure Process ◽  
Time Interval ◽  
Specific Load ◽  
Incipient Melting ◽  
Creep Failure ◽  
Creep Tests ◽  
Covalent Bonds ◽  
Tail Tendon ◽  
Rat Tail

Creep tests were performed on rat tail tendons at each of six temperatures: 25, 30, 35, 40, 45, and 50°C. It was found that the time interval from load application to rupture was related to the applied (specific) load and the temperature. Over the range 25° to 45°C this relation was found to be reasonably approximated by a Tobolsky-Eyring rate equation, if a squared term in specific load was added to the numerator of the exponent. Deviation of the 50°C data from this equation was hypothesized to be associated with incipient “melting”. The apparent activation energy for the failure process was sufficiently high to suggest that the creep failure of tendon involves the breaking of covalent bonds.

scholarly journals Uniaxial Compression Creep Relaxation and Grading of Coal Samples via Tests on the Progressive Failure Characteristics

Geofluids ◽  
2019 ◽  
Vol 2019 ◽  
pp. 1-13 ◽  
Author(s):  
Zuqiang Xiong ◽  
Changsheng Song ◽  
Chengdong Su ◽  
Xiaolei Wang ◽  
Cheng Wang ◽  
...  
Keyword(s):  
Uniaxial Compression ◽  
Yield Curve ◽  
Progressive Failure ◽  
Failure Process ◽  
Thin Sheet ◽  
Strain Curve ◽  
Mechanical Parameters ◽  
Creep Failure ◽  
Creep Tests ◽  
Failure Characteristics

An RMT-150B electrohydraulic servo testing system was used to perform uniaxial compression and uniaxial grading relaxation (creep) tests. The deformation, strength, and failure characteristics of the progressive failure process of coal samples under three loading modes were analyzed. The analysis results show that the prepeak stress-strain curve of the coal samples and the load relationships are not clear and that the whole compression process of coal still showed compression, elastic, yielding, and failure stages. The local stress drop characteristics during our relaxation creep grading tests showed no clear peak value and showed a yield curve with the shape of a conventional single plateau. The values of the mechanical parameters of axial compression were significantly higher than those obtained in the grade relaxation (creep) tests, which showed the mechanical parameters of coal samples with aging characteristics. In the relaxation (creep) tests, when the stress ratio was less than 70%, the relaxation (creep) characteristics of the sample were not clear. When the ratio of stress relaxation (creep) was more than 70% in the relaxation (creep) tests during displacement (stress) with a constant relaxation (creep) over the duration of the test, the evolution, development, and convergence of microcracks in the coal samples were observed. Relaxation (creep) stress was higher, failure duration was shorter, and the duration of failure was longer. For fully mechanized coal faces, increasing the support resistance and timely moving the support after coal cutting may prevent rib spalling accidents by reducing coal stress and exposure time in the front of the working face. Additionally, routine uniaxial compressive failures showed a simple form, having a clear tension-shear dual rupture surface. The staged relaxation creep failure testing of coal is more complex. The entire coal samples were divided into many thin-sheet debris via gradual collapse and shedding, and the number of cracks increased significantly, showing evident lateral expansion characteristics that are similar to the rib spalling characteristics in high coal mining working faces.

scholarly journals Chromatographic Fractionation of Acetic Acid-solubilized Rat Tail Tendon Collagen

1960 ◽  
Vol 235 (4) ◽  
pp. 989-994
Author(s):  
Alexander Kessler ◽  
Hyman Rosen ◽  
Stanley M. Levenson
Keyword(s):  
Acetic Acid ◽  
Chromatographic Fractionation ◽  
Tail Tendon ◽  
Rat Tail ◽  
Tendon Collagen

Polarization-dependent optical second-harmonic imaging of a rat-tail tendon

2002 ◽  
Vol 7 (2) ◽  
pp. 205 ◽  
Author(s):  
Patrick Stoller ◽  
Beop-Min Kim ◽  
Alexander M. Rubenchik ◽  
Karen M. Reiser ◽  
Luiz B. Da Silva
Keyword(s):  
Second Harmonic ◽  
Harmonic Imaging ◽  
Tail Tendon ◽  
Rat Tail

scholarly journals KINETICS OF PALM OIL TRANSESTERIFICATION IN METHANOL WITH POTASSIUM HYDROXIDE AS A CATALYST

2010 ◽  
Vol 8 (2) ◽  
pp. 219-225
Author(s):  
Yoeswono Yoeswono ◽  
Triyono Triyono ◽  
Iqmal Tahir
Keyword(s):  
Activation Energy ◽  
Palm Oil ◽  
Rate Constants ◽  
Potassium Hydroxide ◽  
Catalyst Concentration ◽  
Time Interval ◽  
Pseudo First Order Reaction ◽  
Exponential Factor ◽  
Potassium Methoxide ◽  
First Order

A study on palm oil transesterification to evaluate the effect of some parameters in the reaction on the reaction kinetics has been carried out. Transesterification was started by preparing potassium methoxide from potassium hydroxide and methanol and then mixed it with the palm oil. An aliquot was taken at certain time interval during transesterification and poured into test tube filled with distilled water to stop the reaction immediately. The oil phase that separated from the glycerol phase by centrifugation was analyzed by 1H-NMR spectrometer to determine the percentage of methyl ester conversion. Temperature and catalyst concentration were varied in order to determine the reaction rate constants, activation energies, pre-exponential factors, and effective collisions. The results showed that palm oil transesterification in methanol with 0.5 and 1 % w/w KOH/palm oil catalyst concentration appeared to follow pseudo-first order reaction. The rate constants increase with temperature. After 13 min of reaction, More methyl esters were formed using KOH 1 % than using 0.5 % w/w KOH/palm oil catalyst concentration. The activation energy (Ea) and pre-exponential factor (A) for reaction using 1 % w/w KOH was lower than those using 0.5 % w/w KOH.   Keywords: palm oil, transesterification, catalyst, first order kinetics, activation energy, pre-exponential factor

scholarly journals A damage model for collagen fibres with an application to collagenous soft tissues

2020 ◽  
Vol 476 (2236) ◽  
pp. 20190821
Author(s):  
Gerhard A. Holzapfel ◽  
Ray W. Ogden
Keyword(s):  
Soft Tissues ◽  
Damage Model ◽  
Three Dimensional ◽  
Collagen Fibres ◽  
Physiological Loading ◽  
Cross Links ◽  
Complex Boundary ◽  
Tail Tendon ◽  
Similar Basis ◽  
Rat Tail

We propose a mechanical model to account for progressive damage in collagen fibres within fibrous soft tissues. The model has a similar basis to the pseudoelastic model that describes the Mullins effect in rubber but it also accounts for the effect of cross-links between collagen fibres. We show that the model is able to capture experimental data obtained from rat tail tendon fibres, and the combined effect of damage and collagen cross-links is illustrated for a simple shear test. The proposed three-dimensional framework allows a straightforward implementation in finite-element codes, which are needed to analyse more complex boundary-value problems for soft tissues under supra-physiological loading or tissues weakened by disease.

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