Search results for "Structural engineering"
showing 10 items of 1998 documents
Effects of shape of transverse cross-section on the load carrying capacity of laminated glass columns
2014
Abstract In this paper simplified expressions for the calculus of the load carrying capacity of glass columns having rectangular, tee (T) and cruciform (X) transverse cross-sections are proposed and verified against available experimental data. Members with T and X cross-sections are obtained by gluing single multilayered glass panels. The expressions derived take into account of the: shape of the transverse cross-section (rectangular, T, and, X sections); buckling phenomenon (flexural and torsional); failure in the glued sections; long time effects. Case of full connections and absence of connections are considered to determine the range of variation of expressions adopted. The comparison …
LEM for twisted re-entrant angle sections
2014
In this paper an innovative numerical method named as line element-less method, LEM, for finding solution of torsion problem has been extended to all shaped sections, including sections possessing re-entrant angles at their boundary. The response solution in terms of shear stress field or Prandtl function or warping function in all domain and for any kind of domain with arbitrary contour, may be performed quickly, calculating line integrals only. The method takes full advantage of the theory of analytic complex function and is robust in the sense that returns exact solution if this exists. Numerical implementation of LEM has been developed using Mathematica software without resorting to any…
Photoelastic stress analysis assisted evaluation of fracture toughness in hydrothermally aged epoxies
2014
The present work has investigated the fracture toughness of a model DGEBA epoxy system subject to Hidro-Thermal aging. A Photoelastic Stress Analysis technique has been implemented, showing the evolution of stresses arising throughout the water uptake process due to the non-uniform swelling of the material. Gravimetric and Dynamic Mechanical Thermal Analyses have further complemented the characterization, showing the onset of plasticization effects with aging. The correlation of all previous characterizations has allowed to conclude that an increase of KIC fracture toughness is obtained at the fully saturated condition. In particular Photoelasticity has also revealed the onset of relevant s…
Effects of fiber orientation of adjacent plies on the mode I crack propagation in a carbon-epoxy laminates
2011
Abstract The influence of ply orientation on the resistance to mode I delamination of multidirectional composite laminates can be assessed by Double Cantilever Beam (DCB) tests. However, one of the difficulties associated with such a study is the change in overall elastic parameters occurring when modifying local ply orientations. The present work uses laminates with special stacking sequences allowing for isolating the orientation parameter. Multidirectional DCB specimens were designed so as to obtain an uncoupled quasi isotropic and quasi-homogeneous elastic behavior, with the same properties for the entire laminate and the two sub laminates separated by the pre crack at mid-plane. The re…
Evaluation of toughness by finite fracture mechanics from crack onset strain of brittle coatings on polymers
2008
Crack onset strain measurements of a confined layer in tension provide the means for layer toughness estimation. The procedure can be simplified if steady-state conditions prevail starting from the commencement of crack propagation, an assumption frequently employed in energy release rate evaluation. It is demonstrated, by numerical analysis of experimental data, that an estimate of the defect size in the film is needed in order to reliably evaluate its fracture toughness from the crack onset strain. Only if microcracks of sufficient size are present in the brittle layer, the steady-state energy release rate at the crack onset strain can be identified with layer toughness. Otherwise, the to…
PM—Power and Machinery
2001
Abstract In both the OECD Code and the EC Directive for testing dual-pillar front-mounted roll-over protection structures for narrow track width tractors, a non-continuous rolling preliminary test in case of lateral overturning is provided. This test can be simulated with a computer programme. The role of the tyres (and also of the rims) in the lateral overturning of narrow tractors is very important. Frequently the same tractor can be alternatively equipped with four, five, or more different tyre combinations, which can vary its total mass, width, centre of gravity position and moment of inertia about its longitudinal axis. According to the Standards the preliminary test must be carried ou…
Symmetric Galerkin BEM for Non Linear Analysis of Historical Masonries
2015
The preservation of the historical and monumental buildings, but also of the considerable heritage of old constructions made by traditional techniques, is one of the actual problems of the structural mechanics. The level of knowledge of their structural behavior in presence of external actions is made through calculus methods and simple procedures in order to allow a reading of the material suffering degree and as a consequence of the related safety. Unfortunately, often the masonry panels show openings located in an irregular way and cracks having small or big dimensions. In these cases the employment of strategies, as for example the identifying of the masonry piers and the transformation…
Trip Characteristics Analysis of the Effects of a Travel Behavior Change Program
2018
[EN] Travel behavior change programs (TBCP) are measures or actions specifically designed to motivate people to reduce their car use. This study contributes to the literature on rigorous evaluation of the effects of participating in TBCP. In particular, we analyze the effect of TBCP in relation to a potential for a reduction in car use. In contrast to previous studies, the effect of TBCP is analyzed considering two characteristics of the trip: travel companion and time of trip. The TBCP, consisting of three persuasion actions customized to the needs of the participants in the research, was designed and implemented in Valencia (Spain). To evaluate the effects of participating in the TBCP, a …
Viability of new road infrastructure with heterogeneous users
2011
This paper explores the importance of heterogeneity in value of time and route choice when assessing the viability of new road infrastructure to alleviate congestion problems. The model incorporates strategic interaction between road operators in a cost-benefit framework and several competitive regimes are considered. It is then employed to establish the financial and socio-economic viability of a congestion pricing demonstration entering Madrid city centre, where road users have to choose between a free but highly congested road and a priced free-flowing road (semi-private regime). A logit estimation is undertaken with information from a questionnaire among road users in the Eastern Madrid…
On the sensitivity of bridge seismic response with local soil amplification
1998
The paper presents a numerical sensitivity study of the local site effects on structural response. Following a recently developed model of spatial coherency and a concept of a simple site coefficient the local site effects are modelled as filtrations of excitation processes with a frequency shift. An analysis of a bridge response with supports founded on different soils is carried out. The joint effects of dynamic response and pseudostatic motion are considered. Two types of response are analysed: longitudinal and transverse. The differences between dynamic displacements and force responses are pointed out.