Search results for "Critical load"
showing 8 items of 8 documents
Developing an indicator-modelling approach to forecast changes in nitrogen critical load exceedance across Europe arising from agricultural reform
2011
International audience; Atmospheric nitrogen (N) deposition above the critical load causes eutrophication with adverse impacts on biodiversity. Average Accumulated critical load Exceedance (AAE) is a measure of the amount of critical load exceedance and the area of habitat which is affected, and has been adopted in Europe as a pressure indicator for biodiversity. In Europe, AAE is calculated by the Coordination Centre for Effects (CCE) of the United Nations Economic Commission for Europe based on modelled nitrogen deposition and country-level reporting of critical load thresholds and ecosystem area. Due to differences in country-level reporting, AAE values for semi-natural habitats may show…
Numerical analysis of composite plates with multiple delaminations subjected to uniaxial buckling load
2006
Abstract In this paper the buckling and post-buckling behaviour of unidirectional and cross-ply composite laminated plates with multiple delaminations has been studied. Finite elements analyses have been performed, using a linear buckling model, based on the solution of the eigenvalues problem, and a non-linear one, based on an incremental-iterative method. With non-linear method large displacements have been taken into account and also contact constraints between sublaminates have been added to avoid their interpenetration. It has been found that both delamination length and position and stacking sequence of the plies influence the critical load of the plate; furthermore, linear and non-li…
Moment-Axial Domain of Corroded R.C. Columns
2018
In the present paper, a simplified model to determine the moment-axial force domain of the cross-section of reinforced concrete columns subjected to corrosion process is presented. The model considers members with square and rectangular cross-sections and it accounts for cover spalling, buckling of longitudinal reinforcing bars, loss of bond of bar in tension, reduction of confinement pressures (due to the reduction of the area of stirrups and cracking of concrete induced by rust formation). The analytical expressions for prediction of the area reduction of steel, bond strength and critical load of longitudinal bars utilized were verified against experimental data available literature.
Home energy management system : a home energy management system under different electricity pricing mechanisms
2014
Masteroppgave i fornybar energi ENE 500 Universitetet i Agder 2014 Peak demand is a severe problem in the electricity grid and it was solved by supply side management in the past. But nowadays the demand side management sources have drawn attention due to the economic and environmental constraints. Demand side management in the domestic sector can play an important role in reducing the peak demand on the power system network. It can help in reducing stress and overloading on the transmission and distribution lines. In many countries there are various demand response programs implemented for industrial and commercial loads. In these programs load control is primarily achieved by various type…
Moment-axial force domain of corroded R.C. columns
2016
In the present paper, a simple model to determine the moment-axial force domain of the cross-section of reinforced concrete (R.C.) columns subjected to corrosion process is presented. The model considers members with square and rectangular cross-sections and it accounts for—cover spalling; buckling of longitudinal reinforcing bars; loss of bond of bar in tension; reduction of confinement pressures (due to the reduction of the area of stirrups and cracking of concrete induced by rust formation). The analytical expressions for prediction of the area reduction of steel, bond strength and critical load of longitudinal bars utilized were verified against experimental data available in the litera…
Laminated Glass Members in Compression: Experiments and Modeling
2014
It is well known that structural glass members are made by assembling thin laminated panels, which can be connected with different bonding techniques; for instance, with steel devices or with structural adhesives. The latter are very commonly used because they do not reduce the transparency of the member and make it possible to avoid stress concentrations because of the presence of holes. This technique is used to make up columns in glazing structures and different applications of the technique can be found in contemporary architecture. As evidenced by the literature, one of the most important problems in such members is caused by buckling phenomena, resulting from the slenderness of the pa…
Robustness of Empirical Vibration Correlation Techniques for Predicting the Instability of Unstiffened Cylindrical Composite Shells in Axial Compress…
2020
Thin-walled carbon fiber reinforced plastic (CFRP) shells are increasingly used in aerospace industry. Such shells are prone to the loss of stability under compressive loads. Furthermore, the instability onset of monocoque shells exhibits a pronounced imperfection sensitivity. The vibration correlation technique (VCT) is being developed as a nondestructive test method for evaluation of the buckling load of the shells. In this study, accuracy and robustness of an existing and a modified VCT method are evaluated. With this aim, more than 20 thin-walled unstiffened CFRP shells have been produced and tested. The results obtained suggest that the vibration response under loads exceeding 0.25 of …
Buckling of Elastic Beam Under Unilateral Constraint
1988
ABSTRACT A criterion is proposed to calculate the critical load of a continuous beam under unilateral constraint. The beam is assumed to be built in at the ends and to rest on equally spaced elastic supports, that have equal stiffness. The problem is solved by determining the length of the half-wave of the buckled shape, the number of supports involved, and their position with respect to the end of the half-wave. The analysis model thus defined is determined in relation to the geometry of the beam and to the ratio between the stiffness of the supports and the shearing stiffness of the generic span. It is shown that there exists a limiting value of this ratio, below which the critical load i…