Search results for "shear"
showing 10 items of 804 documents
Fibrous reinforced concrete beams in flexure: Experimental investigation, analytical modelling and design considerations
2008
Abstract The flexural behavior of plain and fibrous reinforced concrete (FRC) beams under monotonic and cyclic actions was analysed. Twelve beams were reinforced with top and bottom longitudinal deformed steel bars and transverse steel stirrups. Concrete, having 30 MPa cylindrical strength, was reinforced with hooked steel fibres at a volume percentage of 1%. Beams, 600 mm in length and with a square side cross-section of 150 mm, were tested in flexure using a three point bending test, adopting three different cover thicknesses of 5, 15 and 25 mm, respectively. The results obtained show that the addition of fibers increases the bearing capacity of the beams and ensures more ductile behaviou…
Preliminary analysis of mastication dynamics and fragmentation during chewing of brittle cereal foods
2013
We studied the masticatory behaviour of five commercial brittle cereal foods, with different formulations, shapes and mechanical properties, chewed by an individual. The investigation of oral behaviour consisted in a simultaneous recording of jaw kinematics and muscle activity by electromyography (EMG) and we also determined the food size distribution at the swallowing point by image analysis. Similar behaviour was found for the evolution of all criteria, and especially the predominance of compression, which could be attributed to the brittle behaviour of the foods. The amplitude of the jaw motion decreased with the number of chewing cycles, or sequence duration, whereas the maximum mastica…
Structural Behavior of Telescopic Steel Pipe for a Full-Scale 60 kW Wind Turbine Tower
2020
A simple analytical model, including local effects due to buckling and shear to moment interaction, was developed to pre-dict the load-carrying capacity of CHS tubes under flexure and shear. A finite-element analysis with ABAQUS Code was also conducted for validation of the proposed model. By properly modeling the imperfection effects due to the ovalization of steel tube, a good correlation of the structural response and failure mode was also achieved, and a good correlation with the analytical model was also achieved. Numerical and analytical results were compared with experimental results recently obtained by the author with good agreement. Experimental tests refer to full-scale static te…
A Non-Local Two Dimensional Foundation Model
2012
Classical foundation models such as the Pasternak and the Reissner models have been recently reformulated within the framework of non-local mechanics, by using the gradient theory of elasticity. To contribute to the research effort in this field, this paper presents a two-dimensional foundation model built by using a mechanically based non-local elasticity theory, recently proposed by the authors. The foundation is thought of as an ensemble of soil column elements resting on an elastic base. It is assumed that each column element is acted upon by a local Winkler-like reaction force exerted by the elastic base, by contact shear forces and volume forces due, respectively, to adjacent and non-…
A thermodynamics-based formulation of gradient-dependent plasticity
1998
Abstract A nonlocal thermodynamic theoretical framework is provided as a basis for a consistent formulation of gradient-dependent plasticity in which a scalar internal variable measuring the material isotropic hardening/softening state is the only nonlocal variable. The main concepts of this formulation are: i) the ‘regularization operator’, of differential nature, which governs the relation between the above nonlocal variable and a related local variable (scalar measure of plastic strain) and confers a unified character to the proposed formulation (this transforms into a formulation for nonlocal plasticity if the regularization operator has an integral nature); ii) the ‘nonlocality residua…
CVBEM solution for De Saint-Venant orthotropic beams under coupled bending and torsion
2014
The aim of this paper is to provide a solution for the coupled flexure–torsion De Saint Venant problem for orthotropic beams taking full advantage of the complex variable boundary element method (CVBEM) properly extended using a complex potential function whose real and imaginary parts are related to the shear stress components, the orthotropic ratio and the Poisson coefficients. The proposed method returns the complete stress field and the unitary twist rotation of the cross section at once by performing only line integrals. Numerical applications have been reported to show the validity and the efficiency of the proposed modified CVBEM to handle shear stress problems in the presence of ort…
Complex Potential Function in Elasticity Theory: shear and torsion solution through line integrals
2012
Aim of this paper is to introduce a basis formulation framed into complex analysis valid to solve shear and torsion problems. Solution, in terms of a complex function related to the complete tangential stress field, may be evaluated performing line integrals only. This basis formulation framed into elasticity problems may be a useful support for a boundary method to verify the accuracy of an approximation of function solution. The numerical applications stress the latter point and show the validity of these formulas since exact solutions may be reached for sections where the exact solution is known.
A four-node MITC finite element for magneto-electro-elastic multilayered plates
2013
An isoparametric four-node finite element for multilayered magneto-electro-elastic plates analysis is presented. It is based on an equivalent single-layer model, which assumes the first order shear deformation theory and quasi-static behavior for the electric and magnetic fields. First, the electro-magnetic state of the plate is determined in terms of the mechanical primary variables, namely the generalized displacements, by solving the strong form of the magneto-electric governing equations coupled with the electro-magnetic interface continuity conditions and the external boundary conditions. In turn, this result is used into the layers constitutive law to infer the equivalent single-layer…
Generalized Fatigue Criterion of maximum shear and normal strains on the fracture plane for materials under multiaxial random loadings
1991
A generalized fatigue criterion for materials under multiaxial random loadings is presented. The criterion is based on the assumption that shear and normal strain on the expected fracture plane – shear strain in one direction on this plane is considered – determine the fracture plane. It has been shown that the well known fatigue criteria of maximum normal strain, maximum shear strain and the criterion of maximum shear and normal strains on the critical shear plane result from the newly formulated criterion.
First GPS-tracking of Cory’s shearwater in the Mediterranean Sea.
2010
Abstract The behaviour and ecology of seabirds such as albatrosses, petrels and shearwaters have been the subject of numerous studies, often employing the most recent technologies to track birds during their foraging trips. Until now, however, large oceanic species have been preferred for tracking studies because of the dimensions and weight of the devices available. New light-weight GPS (Global Positioning System) loggers (< 9 g) were used to track foraging trips of a medium-sized species, the Cory's shearwater, for the first time in the Mediterranean Sea. The tracks obtained showed that Mediterranean Cory's shearwaters alternatively used one of two different fishing areas. Various explana…