11/07/1994 - Balanced Man Scholarship Joshua Renken.pdf

this paper, a method is proposed to define the geometrical contact constraints. Within this treatment one has the possibility to define locally the contact parameters for an accurate treatment of contact constraints. Local values of the geometrical variables can be determined at the integration points, hence the method permits to integrate contact constitutive laws along contact segments. The weak form for this new formulation is developed. Furthermore, also the consistent linearization is carried out. Finally a technique is proposed to reduce the large number of terms involved. In this case, an almost consistent tangent stiffness is determined. @ 1998 Elsevier Science Ltd. All rights reserved

A non-linear stress-strain relation endowed with fractional derivative elements

In this paper a non linear stress-strain relation based on an integral formulation with a power-law kernel is proposed. This constitutive law is able to reproduce both the viscoelastic behavior and the inelastic irreversible phenomenon. It is shown how the proposed stress-strain law is capable to fit experimental data obtained from tensile tests on two kind of metal alloys. Such best-fitting procedure have shown the accuracy of the proposed model and its results are compared to other ones obtained with the aid of classical non-linear constitutive law

A non-linear stress-strain relation endowed with fractional derivative elements

In this paper a non-linear stress-strain relation based on an integral formulation with a power-law kernel is proposed. This constitutive law is able to reproduce both the viscoelastic behavior and the inelastic irreversible phenomenon. It is shown how the proposed stress-strain law is capable to fit experimental data obtained from tensile tests on two kind of metal alloys. Such best-fitting procedure have shown the accuracy of the proposed model and its results are compared to other ones obtained with the aid of classical non-linear constitutive law

Fractional viscoelastic cohesive zone model with long-range interaction

This paper is devoted to model the time-dependent crack propagation along a nonlocal viscoelastic in- terface. We consider this kind of problem where two main aspects of the mechanical behavior influence the crack propagation, namely, the long-range interaction and the rheological phenomena

Life safety assessment in multi-storey building fires

Life safety is one of the most important objectives of Performance Based Fire-Design and is commonly considered to be achieved if building occupants escape the effects of the fire unharmed. Numerical simulations are often used to predict fire dynamics and factors affecting the evacuation capabilities of occupants. The main scope of this research is to assess life safety in a multi-storey building fire. Statistics based fire risk assessment is used to choose the scenario to be simulated taking into consideration the damage severity and likelihood of occurrence. In the fire simulations, particular attention is given to the fuel modelling to consider the toxicity of combustion products and thus, its effects on the building occupants. Fire simulations results are then integrated with evacuation simulations. The fire risk assessment and fire/evacuation simulations are performed for a multi-storey hotel building located in Lecce, Italy

Modelling of the carburizing and nitriding processes

The thermo-chemical diffusion process of carburizing and nitriding was modeled in the present study. The analyses led to the prediction of surface hardened layers dimensions and hardness in commercial steels. A diffusion model based on Fick’s laws was applied to such steels in order to describe the growth kinetics of layers, then the analytical model was employed to perform finite element calculations. In such a way it was possible to calculate the carbon and nitrogen concentration in the cross sections of cylindrical samples and the consequent hardness profiles coupled with those of the residual stresses. The results from analytical model and FE calculations were compared with experimental data