Search results for "Loading rate"
showing 6 items of 16 documents
Effect of the loading rate on ultimate strength of composites. Application: Pressure vessel slow burst test
2013
International audience; The strength of unidirectional elastic fibre composites is shown to depend on the loading rate as the viscoelastic nature of the matrix results in a fall in breaking load as the rate is reduced. The simulation of the accumulation of fibre breaks leading to failure, takes into account all physical phenomena involved fibre failure, including the stochastic nature of fibre strength, stress transfer through the matrix between reinforcements, interfacial debonding and the viscoelastic nature of the matrix. The kinetics of composite failure are seen to involve the initial formation of random fibre breaks which at higher loads coalesce into clusters of broken fibres. The ra…
1980
Compression creep and stress-relaxation tests have been performed on PMMA at several deformations after the sample yielding. At large loading rates, the behaviour observed was found significantly affected by the temperature rise due to the plastic deformation. Creep and stress-relaxation data taken holding the samples at constant temperature after the material loading could be collected into single curves by means of a time shift factor proportional to the loading rate. Retardations- und Relaxationsuntersuchungen bei Druckbeanspruchung von PMMA wurden bei verschiedenen Deformationen oberhalb des Fliespunktes durchgefuhrt. Bei hohen Beanspruchungsgeschwindigkeiten wurde festgestellt, das das…
Integrated production of biopolymers with industrial wastewater treatment: Effects of OLR on process yields, biopolymers characteristics and mixed mi…
2022
The production of polyhydroxyalkanoates (PHA) using industrial wastewaters as feedstocks is a current and challenging topic. This study investigated the production of biopolymers by a mixed microbial culture under different OLRs equal to 1 kgCOD m-3d-1 (Period 1), 2 kgCOD m-3d-1 (Period 2) and 3 kgCOD m-3d-1 (Period 3). The maximum PHA content was achieved in Period 2 (0.38 gPHA gTSS-1), whereas lower values were obtained in Period 1 (0.13 gPHA gTSS-1) and Period 3 (0.26 gPHA gTSS-1). Overall, the maximum PHA productivity resulted equal to 0.08 gPHA L-1h-1 (P2), 0.05 gPHA L-1h-1 (P1) and 0.04 gPHA L-1h-1 (P3), respectively. The molecular weight of the PHA increased from Period 1 (250 kDa) t…
LARGE DEFORMATION CREEP BEHAVIOR OF A SOLID POLYMER.
1981
Abstract The effect of loading rate and strain on the creep behavior after sample yielding has been studied in previous communications (14–15) for Mylar in tension and for Lexan in compression. In this work the creep behavior of Lexan samples previously elongated is considered both in tension and in compression. A procedure which collects all the data independently of both loading rate and initial creep strain is proposed.
Anaerobic dynamic membrane bioreactors for high strength wastewater treatment
2013
A laboratory scale external anaerobic dynamic membrane bioreactor (AnDMBR) treating high strength wastewater was operated to assess the effect of gas sparging velocity and organic loading rate on removal efficiency and dynamic membrane (DM) filtration characteristics. An increase in gas sparging velocity (GSV) results in a decrease in DM filtration resistance. DM or cake formation was identified as the main contribution to the total filtration resistance. Over 99% COD removal was obtained in the study regardless of the GSV. The results showed that the DM formation process proceeded until a stable cake layer thickness was reached. An effective pollutant removal and high permeate quality was …
Benchmark study of undrained triaxial testing of Opalinus Clay shale: Results and implications for robust testing
2021
Triaxial testing of argillaceous rocks and shales is significantly more challenging than conventional rock mechanical testing. The challenges are mainly related to the very low permeability of these geomaterials, and their sensitivity to exposure of atmosphere and brines, which induces variations of water content, suction and effective stress. There are currently no international standards to guide service laboratories for robust testing procedures for shales. A benchmark study of undrained triaxial testing was therefore initiated with three leading service laboratories in shale testing, performing 13 tests and using two different methods of establishing sample saturation prior to deformati…