Search results for "Compres"

Coupled hydro-mechanical analysis of compacted bentonite behaviour during hydration

2021

Abstract This study analyses the response of compacted bentonites upon hydration based on a coupled hydro-mechanical elasto-plastic framework. As an alternative to multi-porosity interpretation, the framework was selected based on the experimental evidence of adsorbed water behaviour in bentonites and the volumetric response at saturated states, apparently independent of its initial state. Based on these premises, a water retention model was formulated using an explicit distinction between adsorbed water and free water, enabling the postulation of the water properties and behaviour depending on its state. In order to effectively account for the transition between unsaturated to saturated st…

BCD-01 JOINT INFLUENCE OF TRANSVERSE COMPRESSION AND SHEAR-FLEXURAL STIFFNESS ON RUBBER V-BELT MECHANICS(BELT AND CHAIN DRIVES)

2009

Evaluation of continuous filament mat influence on the bending behaviour of GFRP pultruded material via Electronic Speckle Pattern Interferometry

2017

Abstract Pultrusion is a process allowing the production of unidirectional (roving) fibre-reinforced polymer (FRP) structural elements with constant cross section. Recently, also civil engineers focused their attention on pultruded composite materials as alternative to traditional ones (e.g., concrete, steel). Furthermore, to improve the transverse strength and stiffness with respect to the fibres direction, continuous filament mat (CFM) is often placed within the stacking sequence. The CFM influence on the global mechanical behaviour is not considered by appropriate actual international standards. In this paper, the influence of the CFM layers on the mechanical behaviour of glass fibres pu…

Scale effect of the tensile strength of flax-fabric-reinforced polymer composites

2011

The development of UD natural fiber composites, considered for application as structural materials, necessitates evaluation of the scale effect of their strength. Alignment of the fibers in flax bast fiber composites can be achieved by employing textile reinforcement, such as yarns and fabrics. Cutting specimens for mechanical tests out of such textile-reinforced composite plates results in a complex non-uniform reinforcement structure at their edges, which may affect the strength of specimens. Scale effect of the tensile strength in the fiber direction of flax-fabric-reinforced composites is studied in the current work. A model accounting for both volume and edge effect of the specimens o…

Reactive Layer Assembly Sustains an Interlocked Structure in Green Processed and Scalable High-Performance Layered Wood

2021

Wood can be processed into structural materials by partial removal of lignin and subsequent hot compression. The fundamental challenge of this process is achieving a cost-effective, green, and scal...

Phonons of hexagonal BN under pressure: Effects of isotopic composition

2021

Raman scattering experiments on isotopically enriched hexagonal boron nitride have been performed under pressure up to 11 GPa at room temperature. The sublinear increase of the Raman-active E2g mode frequencies has been characterized. The pressure behavior has been analyzed by means of a bond-stiffness–bond-length scaling parameter γ which takes into consideration the vast differences in a- and c-axis compressibilities. The interlayer shear mode exhibits a γ parameter similar to that of graphite, and the mode frequency in isotopically pure samples separates faster at low pressures as a result of van der Waals interactions. Because of the extremely low a-axis compressibility, the intralayer …

On the Elastic Behavior of a Cross-Ply Composite Pin-Joint with Clearance Fits

1999

The effect of pin/hole clearance fits on the elastic membranal behavior of a cross-ply fiber glass-reinforced epoxy laminate plate loaded in tension through a pin is examined by a finite element nonlinear contact analysis. No a priori assumption is made on the distribution of the contact pressure on the surface of the hole. Friction effects are not included. The numerical results correlate well with Hertzian theory of contact. It is demonstrated that clearance increases the peak compressive stress in the plate up to a factor of 3000% with respect to the perfect-fit case. Clearance also shifts the location of the peak tensile stress towards the pin/hole contact arc and decreases its magnitu…

Energy models for fatigue life estimation under uniaxial random loading. Part I: The model elaboration

2001

The paper contains analysis of the energy models for the fatigue life assessment under uniaxial stress state. From the simulation tests it appears that taking into account the stress and strain signs during determination of the energy density allows one to distinguish the strain energy density at the tension and compression path. Under random loading with the zero expected values for Gaussion processes it leads to the centered stochastic process. A new (basic for damage cumulation) material characteristic can be easily determined by rescaling the widely used standard stress and strain characteristics of cyclic fatigue. A new model of the fatigue life determination has been proposed. This mo…

Octave-spanning coherent supercontinuum generation in a step-index tellurite fiber and towards few-cycle pulse compression at 2 μ m

2021

Abstract We experimentally demonstrate 140-THz bandwidth (at −20 dB) supercontinuum generation in a 10 cm-long all-normal dispersion step-index tellurite fiber pumped by a turn-key femtosecond fiber laser emitting at 2 . 11 μ m at a repetition rate of 19 MHz. The soliton self-frequency shifted thulium-doped fiber mode-locked laser emits initial transform-limited pulses, with 85-fs pulse duration, that are subsequently quasi-linearly chirped (over more than 50 THz) during the above nJ-level nonlinear propagation. Moreover, we numerically demonstrate the possible pulse compression down to 12 fs by means of additional linear propagation in a standard step-index fluoride fiber with anomalous di…

First-principles study of elastic and thermal properties of scheelite-type molybdates and tungstates

2020

Abstract First-principles calculations are carried out to study the physical properties of scheelite-type AMoO4 molybdates and AWO4 tungstates (A = Ca, Sr, Ba, and Pb). We consider two flavors for the exchange-correlation functional, the local-density approximation (LDA) and the generalized gradient approximation (GGA). The second-order elastic constants were determined, and we found that c11 is larger than c33 for the eight investigated compounds. This fact is consistent with the well-known anisotropic compressibility of scheelite-type molybdates and tungstates. The calculated elastic constants are used to determine macroscopic properties which are relevant for applications, such as the bu…