Search results for "stiffne"
showing 10 items of 533 documents
Residual out-of-plane capacity of infills damaged by in-plane cyclic loads
2020
Abstract During earthquakes, infills are subjected to In-Plane (IP) and Out-Of-Plane (OOP) actions. In the case of strong earthquakes, infills may progressively change their mechanical behavior resulting in a reduction of IP and OOP stiffness and strength. Recent earthquakes have proved that the OOP collapse of infills is a diffused mechanism also for buildings designed to resist seismic events in agreement to the most modern codes. This is potentially a very dangerous event with risk for human health. The strong interaction between IP and OOP behavior of infills traduces in a progressive reduction of the OOP strength. The IP damaging loads may cause a loss of the OOP capacity not predicted…
Steel fibre and transverse reinforcement effects on the behaviour of high strength concrete beams
2012
An experimental program was carried out to investigate the influence of fibre reinforcement on the mechanical behaviour of high strength reinforced concrete beams. Eighteen beams, loaded in fourpoint bending tests, were examined by applying monotonically increasing controlled displacements and recording the response in terms of load-deflection curves up to failure. The major test variables were the volume fraction of steel fibres and the transverse steel amount for two different values of shear span. The contribution of the stirrups to the shear strength was derived from the deformations of their vertical legs, measured by means of strain gauges. The structural response of the tested beams …
Mathematical modeling of a vehicle crash test based on elasto-plastic unloading scenarios of spring-mass models
2011
Published version of an article in the journal: The International Journal of Advanced Manufacturing Technology. Also available from the publisher on SpringerLink: htp://dx.doi.org/10.1007/s00170-010-3056-x This paper investigates the usability of spring which exhibit nonlinear force-deflection characteristic in the area of mathematical modeling of vehicle crash. We present a method which allows us to obtain parameters of the spring-mass model basing on the full-scale experimental data analysis. Since vehicle collision is a dynamic event, it involves such phenomena as rebound and energy dissipation. Three different spring unloading scenarios (elastic, plastic, and elasto-plastic) are covered…
RELATIONSHIP BETWEEN VITAMIN D STATUS AND EARLY ARTERIAL CHANGES IN PRIMARY HYPERTENSION. PRELIMINARY DATA
2011
Buckling and post-buckling of variable stiffness plates with cutouts by a single-domain Ritz method
2023
Structural components with variable stiffness can provide better performances with respect to classical ones and offer an enlarged design space for their optimization. They are attractive candidates for advanced lightweight structural applications whose functionalities often impose the presence of cutouts that requires accurate and effective analysis for their design. In the present work, a single-domain Ritz formulation is proposed, implemented and validated for the analysis of buckling and post-buckling behaviour of variable stiffness plates with cutouts. The plate model is based on the first-order shear deformation theory with nonlinear von Karman strain–displacement relationships. The p…
Ventricular-vascular coupling in hypertension: methodological considerations and clinical implications.
2014
The present review is addressed to analyse the complex interplay between left ventricle and arterial tree in hypertension. The different methodological approaches to the analysis of ventricular vascular coupling in the time and frequency domain are discussed. Moreover, the role of hypertension-related changes of arterial structure and function (stiffness and wave reflection) on arterial load and how ventricular-vascular coupling modulates the process of left ventricular adaptation to hypertension are analysed.The different interplay between vascular bed and left ventricle emerges as the pathophysiological basis for the development of the multiple patterns of ventricular structural adaptatio…
Shear Strength of a Compacted Scaly Clay from Suction-Controlled Triaxial Tests
2012
The paper presents the results of an experimental research aimed at investigating the shear strength characteristics of an unsaturated compacted scaly clay. Shear strength was investigated by suction-controlled triaxial compression tests on dynamically compacted samples. Collected results point out that suction effects on stiffness and shear strength can be very different for suction values applied lower or greater than air entry value (AEV), corresponding to the material void ratio.
Elastic waves in random-fibre networks
1997
The propagation of the first displacement maximum of a semi-infinite wavetrain in a two-dimensional random-fibre network is analysed. Model calculations and numerical simulations are used for demonstrating that two qualitatively different wavefront velocities appear in the network. A transient wave, which travels fast and whose amplitude decreases exponentially, dominates the short-time behaviour when the bending stiffness of the fibres is small and the driving frequency is high. This mode can be described by a one-dimensional model. The transient-wave mode propagates even if the bending stiffness of the fibres vanishes, in which case the normal sound velocity is zero. The usual, and slower…
Comparative evaluation of the effect of the substrate thickness and inherent process defects on the static and fatigue performance of FSW and adhesiv…
2021
Abstract This work aims at evaluating the mechanical performance of joints in an AA6016 alloy, manufactured by means of two alternative processes: friction stir welding and adhesive bonding. Given its wide use in industrial fields such as automotive and aeronautics, an overlap configuration of joints was selected for the study, and a specific method based on the overlap length evaluation has been developed to allow comparisons among the cases. Two substrate thicknesses are considered in order to vary the overall joint stiffness, and the effect of such geometrical parameter on the mechanical behavior of the joined system is experimentally investigated. The experimental findings highlight tha…
Application of cohesive-zone models to delamination behaviour of composite material
2012
International audience; The parameters of cohesive elements have to be chosen correctly in the simulation of composite delamination by finite element method: such as interface strength, interface stiffness and shape of cohesive law. The purpose of this work is to investigate their influence on the accuracy of the results obtained. A three-dimensional cohesive-zone model has been established using Ls-dyna to simulate Double-Cantilever-Beam mode I (DCB) and Edge-Notched-Flexure mode II (ENF) tests. The influence of these parameters of cohesive element on the maximum load and the slope of load-displacement curve have been discussed by comparing experimental and numerical results. Four traction…