in this paper, the effect of polypropylene fibers added to concrete on strength and thermal resistance of high strength concrete has been investigated. therefore, five tests have been carried out to reach this goal which it includes; effect of weight percent of polypropylene fibers on mechanical properties of concrete, effect of fiber’s length on the strength of high strength concrete, effect o...

Buckling-driven delamination is considered among the most critical failure modes in composite laminates. This paper examines the propagation of delaminations in a beam under pure bending. A pre-developed analytical model to predict the critical buckling moment of a thin sub-laminate is extended to account for propagation prediction, using mixed-mode fracture analysis. Fractography analysis is p...

in this study, al/gr composites with 5,10,15,20 weight percent of graphite were produced by in-situ powder metallurgy method. the produced powder mixtures were consolidated and sintered at optimum conditions. the resultant composites were solution treated at 495?c and aged at 170?c. the influence of graphite content on the bending strength of composites was studied. the distribution of graphite...

Apatite-wollastonite (A-W)-phlogopite glass-ceramic is considered to be difficult to resorb, but often, it has been incorporated in particulate form to create new bioactive composites for potential maxillofacial applications. With various compositions, the present work has attempted to prepare apatite-wollastonite (A-W)-phlogopite glass ceramic composites, by applying sintering. Here, three-poi...

The effect of an electric field on the bending behavior of [001] oriented and poled relaxor Pb(In1/2Nb1/2)O3–Pb(Mg1/3Nb2/3)O3–PbTiO3 (PIN–PMN–PT) single crystals was measured using a four point bending apparatus with a longitudinal electric field applied to the bar during bending. The surface finish and electric field amplitude were observed to affect the bending strength. Polished surfaces imp...

Strength data from a recently developed apparatus for measuring long-length fiber strength distributions are analyzed in terms of proof test theory for truncated distributions. Data are fitted using Weibull statistics and scaled for bending and tensile lengths ranging from 1 meter to 100 kilometers. Most tensile applications require strength data near the proof stress level. For failure probabi...

Defects and heterogeneities degrade the strength of glass with different surface and subsurface properties. This study uses surface nanostructures to improve the bending strength of glass and investigates the effect of defects on three glass types. Borosilicate and aluminosilicate glasses with a higher defect density than fused silica exhibited 118 and 48 % improvement, respectively, in bending...

In this study, we mechanically strengthened a borosilicate glass wafer by doubling its bending strength and simultaneously enhancing its transparency using surface nanostructures for different applications including sensors, displays and panels. A fabrication method that combines dry and wet etching is used for surface nanostructure fabrication. Specifically, we improved the bending strength of...

This study reviews world literature on the strength-related effect of duration and rate of loading on wood and wood-based materials. Also, early developments are discussed which led to the currently used permanent loading factor of 9/16. Published data on duration of load are reanalyzed and compared. The comparisons suggest that the effect of stress level on duration of stress for wood is great...