Search results for "shear"
showing 10 items of 804 documents
Definition of a laboratory optimization protocol for road bitumen improved with recycled tire rubber
2012
Abstract Bearing in mind the need to answer one of the most frequent needs for civil construction, in general, and major project such as road infrastructures in particular, this paper presents the results of a laboratory experimental study in order to evaluate the performance improvement that is possible to achieve when modifying road bitumen with CRM (Crumb Rubber Modifier) from discarded tire rubber (TR), using a Wet Process. The environmental advantage is double, since the aim of the research is to obtain high performance road bitumen thanks to the re-use of a discarded material, such as the rubber tires, which otherwise would be dumped in scrap-yard. In particular, this experimental stu…
Numerical prediction of the shear response of semi-prefabricated steel-concrete trussed beams
2016
Abstract In this study, the shear behavior of hybrid steel-trussed-concrete beams (HSTCBs) realized with prefabricated steel trusses embedded into a concrete core cast in situ, is investigated by means of Finite Element (FE) numerical simulations. HSTCBs do not behave as classical RC elements nor composite beams. Up to now, there are not specific design criteria in the building codes and the calculation of this type of beams is conducted by means of design-by-testing procedures. The knowledge of the material behavior as well as the understanding of the interaction between materials in contact is the first requirement for the definition of proper design procedures and calculation methods for…
Flexural response of external R.C. beam-column joints externally strengthened with steel cages
2015
Abstract An experimental and theoretical research referred to the flexural behavior of external R.C. joints strengthened with steel cages constituted by steel angles and battens is presented. The subassemblage (beam, column and joint) was subjected to a constant vertical load acting on the column and to a monotonically increasing lateral force applied at the tip of the beam. The control specimen is without strengthening system and it was designed with weak column and strong beam and overstrength in the joint region. Strengthening cases here studied refer to steel caging in the column and both in the beam and in the column. Cyclic response in term of load–displacement curves, crack patterns …
A Note on the Shear Influence on Belt Drive Mechanics
2007
Abstract Belt drives work often with short center distances and very different wrap arcs so that high adherence characteristics are required at the belt-pulley contact. In addition, the belt flexural stiffness reduces the contact width, but this decrease may be compensated in part by the belt softening due to the shear compliance.
The mechanics of continuous chip formation in oblique cutting with single-edged tool — Part I. Theory
1990
Abstract The paper presents a new point of view on oblique cutting mechanics when cutting with a single-edged tool. This is based on the main assumption that plastic flow of material during chip forming occurs in the set of planes normal to the cutting edge. As a consequence of the transformation of various orthocartesian systems some new generalized relationships for kinematics of oblique cutting operation and plastic deformation in the shear zone are derived.
Buckling and Postbuckling of Stiffened Composite Panels with Cracks and Delaminations by Ritz Approach
2017
A Ritz approach for the analysis of buckling and post-buckling of stiffened composite panels with through-the-thickness cracks and/or delaminations is presented. The structure is modeled as the assembly of plate elements whose behavior is described by the First-order Shear Deformation Theory and von Karman’s geometric nonlinearities. Penalty techniques ensure continuity along the edges of contiguous plate elements and the enforcement of the restraints on the external boundaries. They are also used to avoid interpenetration problems. General symmetric and unsymmetric stacking sequences are considered. A computer code has been developed and used to validate the proposed method, comparing the …
Simplified flexural response of steel-fiber reinforced concrete beams
2008
In the present paper, an analytical model is proposed that is able to determine the flexural response of supported beams under four-point bending tests. Cases of normal strength reinforced concrete beams with longitudinal bars in the presence of reinforcing hooked steel fibers and transverse stirrups are considered. A simplified analytical model is presented that is able to calculate the load-deflection curves and the maximum and ultimate deflections occurring in the case of shear or flexure failures. In the case of shear failure, the maximum shear strength of the beams is evaluated by using a recent analytical expression proposed by the author able to account for the shear-to-moment intera…
Generalization of Shear Truss Model to the Case of SFRC Beams with Stirrups
2012
A theoretical model for shear strength evaluation of fibrous concrete beams reinforced with stirrups is proposed. The formulation is founded on the theory of plasticity and the stress field concepts, generalizing a known plastic model for calculating the bearing capacity of reinforced concrete beams, to the case of fibrous concrete. The beneficial effect of steel fibres is estimated taking into account the residual tensile strength of fibrous concrete, by modifying an analytical constitutive law which presents a plastic plateau as a post-peak branch. Around fifty results of experimental tests carried out on steel fibrous concrete beams available in the literature were collected, and a compa…
Shear-thinning fluids for gravity and anisotropy mitigation during soil remediation in the vadose zone
2018
Abstract Surfactant foam has been proposed as an effective treatment fluid for in situ environmental remediation of soils. In the vadose zone, it could improve treatment homogeneity, but its use remains challenging. To better understand and predict foam formation and propagation in vadose zone, we studied them in 24 soils with wide range of properties (including permeability: 2 10−12 to 3.3 10−9 m2). Foam rheology showed to be complex and mostly influenced by soil permeability and grading. Below 2 10−11 m2, foam propagation velocity was not influenced by permeability. Conversely, slight shear thinning to Newtonian behavior was observed for higher permeabilities. Benefits for remediation in …
Influence of Welding Time on Tensile-Shear Strength of Linear Friction Welded Birch (Betula pendula L.) Wood
2015
Linear friction welding of wood is a bonding process applied to wood and during which a stiff bond line is formed by the softening and rehardening of wood components to form a composite material composed mainly of wood fibres embedded in a modified lignin matrix. Unfortunately, the bonds tend to spontaneously delaminate or lose their strength when exposed to moist conditions. Some approaches were previously applied to overcome this problem, but so far a suitable solution has not been found. This paper presents results of applying post-welding thermal modification to reduce the moisture sensitivity of welded wood. The experiments included welding of birch wood, thermal modification under sup…