1,721,028 research outputs found
Prediction of fold eccentricity in the axial axisymmetric plastic progressive collapse of circular tubes
No full textStatic lateral compression of aluminium tubes: Strain gauge measurements and discussion of theoretical models
No full text
Characterization of polymeric structural foams under compressive impact loading by means of energy-absorption diagram
No full textThe mechanical properties at room temperature of three polymeric foams (namely EPP, PUR and PS/PA foams) have been experimentally evaluated in both static and impact loading conditions. The energy absorption characteristics have been examined both through the energy-absorption diagram method and through the efficiency diagram method. The meaning of the efficiency parameter, already used in the literature, has been explained in a proper, satisfactory way. It is shown that the maximum of the efficiency identifies the condition for optimal energy absorption of the foam, while the maximum stress reaches a value limited through other design considerations. The efficiency diagram method is then used to obtain synthetic diagrams useful to characterize the material and to help the design of energy absorbing components. These synthetic selection diagrams are obtained for the three tested materials. Finally, some consideration are drawn comparing the mechanical performance of the three considered types of foams and their dependency on density. © 2001 Elsevier Science Ltd
Mechanical models of the behaviour of plastic materials: Influence of time and temperature
No full textAn inverse method for the identification of strain-rate sensitivity parameters of sheet steels
No full textThermo-mechanical modelling of Dynamic Tensile Extrusion test
No full textRecently, the researchers of the Los Alamos National Laboratory (LANL) have been developed a technique to investigate high strain-rates in which a sphere is launched at high speed (300-800 m/s) through a conical die (Dynamic Tensile Extrusion test). The system can use a set-up similar to a Taylor test (like a light gusgun) but induces in the material high levels of tensile stresses and allows to investigate the fracture and damage of the material in these extreme conditions. Due to the high strain-rates and hydrostatic component of stress that occur during the extrusion in the die, the material is also subject to a rapid heating. In this work, the DTE test has been simulated with the explicit Lagrangian code LSDYNA. In order to correctly reproduce the various aspects of the test it is necessary to use an elasto-plastic material model that takes into account strain-rate, thermal softening, pressure influence and damage and that adequately describes the thermal coupling effects and the equation of state (EOS) of the material. Besides, due to the high distortion of the Lagrangian mesh, the use of a mesh adapting technique is absolutely necessar
Analisi numerica del comportamento di elementi in conglomerato armato semplicemente tesi
No full text- …
