scholarly journals Predicting the master curves of bituminous mastics with micromechanical modelling

Author(s):  
Hassan Fadil ◽  
Denis Jelagin ◽  
Manfred N. Partl
2021 ◽  
Vol 6 (2) ◽  
Author(s):  
Yasser M. Alghrafy ◽  
El-Sayed M. Abd Alla ◽  
Sherif M. El-Badawy

Author(s):  
J. Shi

Scatter in test results is common for relatively brittle materials such as ceramic matrix composites. The scatter may come from differences in material processing conditions, specimen machining/handling and from variations in test parameters for nominally the same test material. Large scatter in test results makes material modeling difficult. In the past, master curve concepts have been proposed to reduce scatter in tensile data and to interpret fatigue/creep results. In this paper, one such concept is examined in detail by applying it to the recent tensile test results of a SiC/SiC composite. It was found that the way to construct master curves did not apply to the CMC studied and thus a new master curve was developed to better represent the tensile data. In addition, the test data were analysed statistically based on the new master curve.


2012 ◽  
Vol 598 ◽  
pp. 473-476 ◽  
Author(s):  
Yong Mei Guo ◽  
Wei Chen

Five SBS modified asphalts and one base asphalt were selected to carry out frequency sweeps over a wider frequency range using the dynamic shear rheometer (DSR). Six asphalt binders were subjected to sinusoidal loading at 30°C-90°C within the linear viscoelastic limits, and master curves of complex modulus (G*) and phase angle (δ) could be constructed by means of the time-temperature superposition principle (TTSP). The results show that the G* values of SBS modified asphalts are significantly greater than those of base asphalt at low frequencies, but are slightly smaller at high frequencies. Compared with the base asphalt, SBS modified asphalts have narrower master curves of complex modulus, and their phase angles are much smaller within the whole frequency range. This indicates that various properties of SBS modified asphalts, such as high-temperature property, low-temperature property, temperature susceptibility and elastic recoverability, are superior to those of the base asphalt. The G* values of the rolling thin-film oven (RTFO) aged asphalt are larger than those of the unaged asphalt in the whole range of frequencies, demonstrating that the anti-rutting performance of asphalt binder is improved after short-term aging.


2007 ◽  
Vol 280-283 ◽  
pp. 1731-1738 ◽  
Author(s):  
Frédéric Osterstock ◽  
Ioannis St. Doltsinis ◽  
Olivier Vansse

Channelled hollow ceramic cylinders have been sliced into discs of equal thickness and submitted to an adapted diametral compression, or brazilian, test such as to evaluate their reliability. The mean Weibull modulus, of m » 18, is representative of a rather good homogeneity of the ceramic material. The shapes of the distributions reveal a probable multimodality. This is analyzed in superimposing possible unimodal distributions of given characteristic value, Weibull modulus and number of items, and comparing to the experimental plot. Iterative modifications are made until a convincing superposition is attained. Complementary numerical simulations on “thermomechanically equivalent microstructures” have been created on the computer observing actual stereological data. The micro-mechanical model accounts for cracking of grain interfaces until specimen separation. Weibull plots for model structures under pore pressure suggest multimodal distributions with moduli ranging as in the measurements. The larger scatter at higher rupture pressures may indicate a varying degree of quasi-brittleness.


1997 ◽  
Vol 119 (3) ◽  
pp. 262-265 ◽  
Author(s):  
S. R. White ◽  
A. B. Hartman

Little experimental work has been done to characterize how the viscoelastic properties of composite material matrix resins develop during cure. In this paper, the results of a series of creep tests carried out on 3501–6 epoxy resin, a common epoxy matrix material for graphite/epoxy composites, at several different cure states is reported. Beam specimens were isothermally cured at increasing cure temperatures to obtain a range of degrees of cure from 0.66 to 0.99. These specimens were then tested in three-point bending to obtain creep compliance over a wide temperature range. The master curves and shift functions for each degree of cure case were obtained by time-temperature superposition. A numerical technique and direct inversion were used to calculate the stress relaxation modulus master curves from the creep compliance master curves. Direct inversion was shown to be adequate for fully cured specimens, however it underpredicts the relaxation modulus and the transition for partially cured specimens. Correlations with experimental stress relaxation data from Kim and White (1996) showed that reasonably accurate results can be obtained by creep testing followed by numerical conversion using the Hopkins-Hamming method.


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