Papers by Keyword: Ductility Index

Abstract: This paper studies that dynamic load affects mechanical properties of materials about composite tail ore different replacement rate, different PVA fiber volume content and different plate thickness. The phenomenon of the tests and results showed that:1) PVA tailings cement-based composite materials has low damage, strong integrity and strong energy dissipation under dynamic loading. 2) When the volume content is 2%, material resistance effect is best. 3) The study proves that 30 mm plate have good ductility and Size effect influence the material mechanics performance. 4) PVA tailings cement-based composite materials under dynamic loads ,as tailings content increases the performance indicators reduced. So the engineering applications recommended replacement rate of the tailings is 50%.

Abstract: Green chemistry approach (hydrothermal process) is utilized for grafting maleic anhydride (MA) into linear low density polyethylene (LLDPE), thereby enhancing the compatiblility of the latter in its blend with polylactic acid (PLA). The grafting of MA into LLDPE is confirmed by Fourier Transform-Infrared Spectroscopy (FT-IR) analysis. LLDPE-g-MA content in PLA matrix is varied as 4% wt., 8% wt. and 12% wt. when preparing glass fiber reinforced PLA/LLDPE-g-MA thermoplastic composite via hot pressing. Single Edge Notch Bend (SENB) specimens have been prepared from the composites and three point bend test was performed.The load-displacement plot of the test results indicates that the ductility index (DI) increased for the samples with increased LLDPE-g-MA content. The observation of the fractured surface of specimens in Scanning Electron Microscope (SEM) suggests that the improved DI value is because of the increased matrix ductility owing to the plasticizing effect of the LLDPE-g-MAH inclusion.

Abstract: Ultra-high toughness cementitious composite (UHTCC) is a PVA fiber reinforced cementitious composite. Tensile strain hardening behavior with ultimate tensile strain of more 3% under direct tensile loading is one of its important characteristics. In the current article, nine simply-supported reinforced UHTCC beams were subjected to four-point bending loading to experimentally investigate the influence of ductile deformation behavior of UHTCC on ductility capacity of reinforced structural members. Ductility index is determined by adopting three different parameters, i.e., deformation capacity, energy dissipation capacity as well as curvature capacity. The effect of longitudinal tensile reinforcement ratios on the variation of ductility in UHTCC reinforced beams was examined. It was found from the experimental results that the combination of ductile matrix (UHTCC) and steel bar prevents from occurrence of localized cracks in pure bending zone, showing high damage tolerance and ductile failure behavior. The results also show that as longitudinal tensile reinforcement ratio increases, deformation ductility and curvature ductility both exponentially decrease while a small reduction is demonstrated for energy ductility at ultimate failure.