Semianalytical Lower-Bound Limit Analysis of Domes and Vaults

The calculation of the collapse load of spherical domes is addressed using a semianalytical approach under the hypothesis of small displacements and perfect plasticity. The procedure is based on the numerical approximation of the self-stress that represents the projection of the balance equilibrium null space on a finite dimensional manifold. The so-obtained self-equilibrated stress span is superimposed onto a finite-element linear elastic solution to the prescribed loads yielding to the statically admissible set accordingly to Melan’s theorem. The compatibility of the stress with the constitutive law of the material was enforced using a linearized limit domain in terms of generalized stress, namely, axial force and bending moment along the local spherical curvilinear coordinates. The procedure was tested with reference to numerical and experimental data from the literature, confirming the accuracy of the proposed method. A comparison with the literature confirms that the buckling load was much greater than the two plastic collapse loads calculated through the proposed procedure and reported in the quoted literature

Experimental and Numerical Evaluation of Residual Displacement and Ductility in Ratcheting and Shakedown of an Aluminium Beam

Safety assessment of structures can be obtained employing limit design to overcome uncertainties concerning actual response due to inelastic constitutive behavior and more generally to non-linear structural response and loads' random variability. The limit analysis is used for evaluating the safety of the structures, starting directly from load level without any knowledge of the load history. In the paper, the lower bound calculation is proposed where a new strain-based approach is used that allowed describing the residual stress and displacement in terms of permanent strain. The strategy uses the permanent strain as effective parameters of the procedure so that it is possible to assess the ductility requirements for the complete load program developed till collapse or shakedown. The procedure is compared to experimental results obtained on aluminum beams in shakedown

Experimental and Numerical Evaluation of Residual Displacement and Ductility in Ratcheting and Shakedown of an Aluminum Beam

Safety assessment of structures can be obtained employing limit design to overcome uncertainties concerning actual response due to inelastic constitutive behavior and more generally to non-linear structural response and loads’ random variability. The limit analysis is used for evaluating the safety of the structures, starting directly from load level without any knowledge of the load history. In the paper, the lower bound calculation is proposed where a new strain-based approach is used that allowed describing the residual stress and displacement in terms of permanent strain. The strategy uses the permanent strain as effective parameters of the procedure so that it is possible to assess the ductility requirements for the complete load program developed till collapse or shakedown. The procedure is compared to experimental results obtained on aluminum beams in shakedown

Experimental investigation on beach morphodynamical process near river mouth

Physical model study on wave influences on river-mouth depositional process is presented. Experiments were performed in a wave basin in order to determine erosion and accretion area due to the combined wave - current flows. An inflow glass channel was designed to reproduce a river mouth model in a 3D wave basin made with a sand bottom. The tests were carried out under three different conditions: River current, waves, wave -current interaction. Measurements of wave heights, beach profiles and bathymetric profiles were made. The results show that in the presence of combined wave-current flows, erosion areas are more evident in vicinity of a mouth with depth and width values greater than depth and width values of inflow channel