We report exceptional ductile behavior in individual double-walled and triple-walled carbon nanotubes at temperatures above 2000 degrees C, with tensile elongation of 190% and diameter reduction of 90%, during in situ tensile-loading experiments conducted inside a high-resolution transmission electron microscope. Concurrent atomic-scale microstructure observations reveal that the superelongatio...

Irregularities are inherent to virtually all fibers, including the conventional textile fibers, the high-performance brittle fibers and newly developed nano-fibers. These irregularities can fall into two main categories: dimensional or geometrical irregularity (external) and structural irregularity (internal). For natural fibers such as wool, diameter variation along fiber length is atypical ex...

In this research, softening and ratcheting behaviors of Ck20 alloy steel cylindrical shells were studied under displacement-control and force-control cyclic axial loading and the behavior of hysteresis curves of specimens was also investigated. Experimental tests were performed by a servo-hydraulic INSTRON 8802 machine. The mechanical properties of specimens were determined according to ASTM E8...

The effect of polymeric coatings on the static fatigue of double-coated optical fibers is investigated. A closed form solution of the tensile stress in the glass fiber under the action of a constant tensile force in the fiber’s axial direction is obtained using viscoelastic theory. The tensile force is applied to the glass fiber and polymeric coatings. The applied tensile fore is gradually tran...

Shale formations show obvious anisotropic characteristics in their mechanical properties due to pronounced bedding planes and natural fractures. This anisotropic behavior generally creates complex fracturing networks and is crucial to gas shale stimulation. Although much research has been done to study the anisotropic compression behaviors of shale with static and quasi-static strain rates, the...

The cornea is a transparent soft tissue covering the front of the eye. The biomechanical properties of the cornea have been commonly investigated by uniaxial tensile and inflation testing methods. The cornea like many other hydrated tissue swells when immersed in an ionic solution. Previous studies on hydrated tissues have shown that mechanical properties and hydration are closely related. The ...

Natural fibers are receiving considerable attention as substitutes for synthetic fiber reinforcements such as glass in polymer due to their low density, low cost, acceptable specific strength, reduced tool wear and respiratory irritation and renewable resources. The fibers are not uniformly distributed in the randomly oriented fiber reinforced hybrid composites due to manual lay-up and fibers a...

BACKGROUND Adhesive systems are constantly subjected to mechanical and chemical stresses that negatively impact the integrity and durability of the dentine-adhesive interface. Despite the lack of evidence to support or reject the clinical indication for mechanical retention, the potential further contribution of these preparations to the behavior of the composite resin-sound dentine bond has be...

Tensile stress develops in concrete when shrinkage deformations and restraints (internal or external) exist. Utilization of appropriate creep or relaxation functions is crucial for assessing stress and the associated cracking potential in concrete, especially at early ages when chemical and physical properties change rapidly. The existing models, developed either from compressive creep tests or...

Fly ash, which consists of hollow particles with porous shells, was introduced into polyurea elastomer. A one-step method was chosen to fabricate pure polyurea and the polyurea matrix for the composites based on Isonate® 2143L (diisocyanate) and Versalink® P-1000 (diamine). Scanning electron microscopy was used to observe the fracture surfaces of the composites. Particle size and volume fractio...