Search results for " Bending"
showing 10 items of 63 documents
Hall effect and electronic structure of films
2010
Abstract Tunneling experiments have shown that in order to retain half-metallicity at room temperature not only a large gap is required but also a Fermi energy considerably distant from the minority band edges. We correlate the position of the Fermi energy in the spin minority gap obtained from band structure calculations to Hall effect experiments. As a model system we chose Co 2 Fe x Mn 1 - x Si , where the Fermi energy was calculated to move from the valence band edge of the minority states to the conduction band edge with increasing x . On high quality laser ablated epitaxial films we observe a sign change of both the normal and the anomalous Hall effect with doping. The experimental da…
Interaction between Longitudinal Shear and Transverse Bending in Prestressed Concrete Box Girders
2017
In box girder bridges, the quantity and distribution of reinforcement to be put in concrete elements of sections can be evaluated only by considering the deformation of the cross section in addition to the longitudinal analysis of the static scheme, establishing the entire state of stress of box sections. This leads to a need to evaluate the interaction between internal forces obtained by the global analysis and the ones obtained by the local analysis of the cross sections. The frame effect implies the elastic deformation of slabs and webs, whereas eccentrically applied loads lead to cross-section distortion with the loss of the box shape. Hence, the reinforcement is strongly influenced by …
Assessment of multiaxial fatigue behaviour of welded joints under combined bending and torsion by application of a fictitious notch radius
2004
Abstract A major problem in the assessment of the multiaxial fatigue behaviour in welded joints is the determination of local notch stresses, since the real local radii in most cases are not known. This can be circumvented by introducing a fictitious notch radius, according to Neuber and Radaj. The calculations of local equivalent stress amplitudes for welded joints (tube–tube and flange–tube) under pure bending, pure torsion and combined in- and out-of-phase bending with torsion can then be carried out by stress-based and strain energy density-based criteria. Among the investigated methods, the most reliable results are obtained with the effective equivalent stress hypothesis, an integral …
The significance of the triceps surae muscle action as a determinant in the biomechanical genesis of ski fall injuries
1985
In an epidemiologic study of 700 ski fall injuries YOUNG /1/ established a classification of the different fall modes involved. In more than 60 % of all falls that lead to an injury he found a forward bending motion of the body which is frequently coupled with a twisting of the body around the lower extremity. This clearly shows the importance of the forward motion component of the skier’s body in ski fall traumatology. The type of injury and its location depend on the action of the ski binding system. If the binding does not release in a ski fall, the fraction of injuries in the lower extremity amounts to nearly 100 %. If the binding does release, however, the injuries ocurring in this cas…
Strength and ductility of confined concrete columns under axial load and biaxial bending
2012
The behaviour of prismatic reinforced concrete columns under increasing eccentric compression load was experimentally investigated and analytically modelled. Columns with distributed longitudinal reinforcement and closely spaced transverse reinforcement were tested up to failure, considering different values and directions of eccentricity. Preliminary tests were carried out under concentric compression in order to validate the choice of the stress-strain laws adopted for the confined concrete and the longitudinal steel bars in compression. In the paper, closed form expressions able to approximate the experimental results in the case of uniaxial bending are presented. Finally, a fibre numeri…
Bending-Shear interaction domains for externally prestressed concrete girders
2013
In prestressed concrete structures, the evaluation of the safety level is generally carried out by separating the bending moment strength and the shear force capacity. Actually interaction between bending moment (M) and shear force (V) can have significant consequences on evaluations in service life, especially when the ultimate limit state (ULS) is considered. In this paper, the M-V interaction is addressed for prestressed concrete girders, in the cases of both bonded and unbonded prestressing tendons. It can be demonstrated, by drawing the interaction domains (M-V), that a significant reduction of the safety level has to be considered when shear force is evaluated together with bending mo…
A dissipated energy comparison to evaluate fatigue resistance using 2PB
2012
Flexural fatigue due to repeated traffic loading is a process of cumulative damage and one of the main failure modes of flexible pavement structures. Typically, micro-cracks originate at the bottom of an asphalt concrete layer due to horizontal tensile strains. Micro-cracking starts to propagate towards the upper layers under repeated loading which can lead to pavement failure. Different approaches are usually used to characterise fatigue resistance in asphalt mixtures including the phenomenological approach, the fracture mechanics approach and the dissipated energy approach. This paper presents a comparison of fatigue resistance calculated for different dissipated energy models using 2 Poi…
Curvature increases permeability of the plasma membrane for ions, water and the anti-cancer drugs cisplatin and gemcitabine
2019
ABSTRACTIn this work the permeability of a model asymmetric plasma membrane, for ions, water and the anti-cancer drugs cisplatin and gemcitabine is studied by means of all-atom molecular dynamics simulations. It is shown that permeability of the membranes increases from one to three orders of magnitude upon membrane bending depending on the compound and the sign of curvature. Our results show that the membrane curvature is an important factor which should be considered during evaluation of drug translocation.TOC GRAPHICS
Size effects on the plastic collapse limit load of thin foils in bending and thin wires in torsion
2011
Abstract Following a previous paper by the author [Strain gradient plasticity, strengthening effects and plastic limit analysis, Int. J. Solids Struct. 47 (2010) 100–112], a nonconventional plastic limit analysis for a particular class of micron scale structures as, typically, thin foils in bending and thin wires in torsion, is here addressed. An idealized rigid-perfectly plastic material is considered, which is featured by a strengthening potential degree-one homogeneous function of the effective plastic strain and its spatial gradient. The nonlocal (gradient) nature of the material resides in the inherent strengthening law, whereby the yield strength is related to the effective plastic st…
Common defects of parts manufactured through single point incremental forming
2021
Single point incremental forming is one of the most intensely researched die-less manufacturing process. This process implies the usage of a CNC equipment or a serial robot which deforms a sheet metal with the help of a relatively simple tool that follows an imposed toolpath. As every cold metal forming process, besides the many given advantages it has also some drawbacks. One big drawback in comparison with other cold metal forming processes is the low accuracy of the deformed parts. The aim of this research is to investigate the sheet metal bending mechanism through finite element method analysis. The results shows that the shape of the retaining rings has a big influence over the final g…