Search results for "strength"
showing 10 items of 2415 documents
Strength and ductility of R.C. columns strengthened with steel angles and battens
2012
Abstract In this paper the behaviour of R.C. members externally strengthened with steel angles and battens subjected to axial force and bending moment is analysed. A fibre model was utilised to predict the moment–curvature diagrams of the strengthened members on the basis of stress–strain curves of the constituent materials (confined concrete, steel bars and angles) recently derived by the author. The stress–strain curves utilised for compressed concrete were able to take into account the confinement effects induced by longitudinal (bars and steel angles) and transverse (stirrups and battens) steel reinforcements. Constitutive laws in compression for confined concrete and steel bars and ang…
Critical Planes in Multiaxial Fatigue
2005
The paper includes a review of literature on the multiaxial fatigue failure criteria based on the critical plane concept. The criteria were divided into three groups according to the distinguished fatigue damage parameter used in the criterion, i.e. (i) stress, (ii) strain and (iii) strain energy density criteria. Each criterion was described mainly by the applied the critical plane position. The multiaxial fatigue criteria based on two critical planes seem to be the most promising. These two critical planes are determined by different fatigue damage mechanisms (shear and tensile mechanisms).
Overstrength requirements to avoid brittle shear failure in RC slender beams with stirrups
2020
Abstract In this paper, an analytical expression was derived for the prediction of shear strength of slender reinforced concrete (RC) beams with stirrups. Failure occurring in B and D regions of the beam was considered. An expression derived for the shear strength of the B region was based on a modified constant angle truss model. The analytical expression derived consisted of three terms. The first one was related to the concrete contribution expressed through the square root of cylindrical compressive strength, geometrical ratio of longitudinal bars, and depth to width ratio. The second one was relating to the shear force induced by yielding of stirrups to the inclination of the main crac…
Flexural Response of RC Beams Failing in Shear
2020
In this paper, an analytical model to determine the flexural response of simply supported RC beams under four-point bending tests failing in flexure and shear is presented. The model is able to provide load-deflection curves, including also the shear contributions, which are determined assuming a kinematic rigid plastic model able to consider different strength contributions such as the concrete, the dowel action, and transverse reinforcement with progressive yielding. For each contribution, a physical explanation is provided to link the strength evaluation with a specific kinematic evolution for the determination of the overall response of RC beams under combined shear and flexural loads. …
Influence of FRP wrapping techniques on the compressive behavior of concrete prisms
2006
Abstract Results of an experimental investigation on the compressive behavior of concrete prisms with square cross-section, externally wrapped with carbon fiber reinforced plastic (CFRP) sheets are presented. The effects of the following parameters were analyzed: local reinforcement at the corners and continuous layers; horizontal and vertical discontinuous strips; number of continuous layers—length of specimens. An analytical model is proposed to determine the maximum bearing capacity of compressed concrete members with square cross-section and externally wrapped with FRP for the different configurations examined, and also able to consider the strength reduction with the length increase of…
A Digital Control System for the Hydraulic Fatigue Stand SHM 250b
2006
Unreliable and inflexible analog control systems of fatigue test stands applied in laboratories are being replaced by systems enabling easy development and implementation of new test ideas. This paper presents a digital control system applied in the fatigue test stand SHM 250b. It is based on a new electronic system and the I/O board RT-DAQ4/PCI with the software Matlab/Simulink used for communication with the board. The control system for the fatigue test stand SHM 250b gives the possibility of performing fatigue tests under controlled strain ε(t), stress σ(t) and energy parameter W(t) which is calculated from the stress and strain signals. The applied control system is now used, depending…
LOAD SUPPORT OF FRC CYLINDERS UNDER COMPRESSION
2000
ABSTRACT The purpose of this research is to look for the optimum structure applied FRC for load support by considering the biomimetic design. For example, cortical bone is made of FRC structures for load support in living bones. Making a start of analysis, the osteon being an structural unit of cortical bone was modelled in filament-wound (FW) cylinder. The first approximation of cortical bone was represented by the densest arrangement of the cylinders to focus on compressive behaviour of osteons. E-glass/epoxy cylinders were applied to specimens. Static compression tests were carried out to evaluate these models. On the osteon model, the smaller ply angle to the longitudinal direction gave…
Theoretical and Experimental Research on Mechanical Behavior of Layered Composites Laminates
2014
The aim of the research of the experiment was to determine the mechanical characteristics of the composite layered material. There has been two types of experimental tests i.e. test for determining the tensile modulus of elasticity of the material, the maximum voltage and the elongation at break of the material. The second type of test is the flexural test was intended to determine the maximum load that the breaking is produced by bending.
A Cap-Model for Masonry-Like Material Constitutive Laws
1995
An accurate description of the constitutive behaviour of masonry-like materials is an essential target for obtaining an effective analysis-tool of masonry structures. In this paper an idealized constitutive model of such materials is proposed taking into account some peculiar features of masonry: -i) a limited strength in compression; -ii) a very limited ability to withstand tensile stresses; -iii) a softening behaviour due to a progressive reduction of the tensile strength during a monotonically increasing loading.
Study of the Formability of Light Metallic Materials
2015
There is a continuing interest in using laminated materials for the production of lightweight parts, the resulting parts having the same functionality and even an increased stiffness and length of operation compared to conventional materials. The present paper aims to study the forming behavior of the laminated materials that requires the unfolding of tests to determine the tensile mechanical properties and the intrinsic properties, determining the forming limit curves by means of the Nakajima test and the analysis of the behavior at unconventional incremental forming.