Choice under Uncertainty with the Best and Worst in Mind: Neo-additive Capacities

The concept of a non-extreme-outcome-additive capacity (neo-additive capacity ) is introduced. Neo-additive capacities model optimistic and pessimistic attitudes towards uncertainty as observed in many experimental studies. Moreover, neo-additive capacities can be applied easily in economic problems, as we demonstrate by examples. This paper provides an axiomatisation of Choquet expected utility with neo-capacities in a framework of purely subjective uncertainty.

From local to global additive representation

This paper studies continuous additive representations of transitive preferences on connected subdomains of product sets. Contrary to what has sometimes been thought, local additive representability does not imply global additive representability. It is shown that the result can nevertheless be established under some additional connectedness conditions. This generalizes previous results on additive representations on (subsets of) product sets

Reliability assessment using combination of polynomial chaos and simulations: application to nonlinear fracture mechanics

This paper presents a probabilistic approach based on polynomial chaos expansion, in order to provide accurate explicit approximation of the structural response to be considered in the limit state function. The main difficulties in this approach are related to the calculation of the expansion coefficients which are defined by multi-dimensional integrals. As an alternative to the quadrature methods, Monte-Carlo simulations based on low discrepancy Halton sequence have been used for this issue. The accuracy and the efficiency of the proposed approach have been approved through analytical models. It is shown that the use of low discrepancy sequence provides more rapidly converging estimates. The proposed approach has been applied to assess the integrity of a cracked pipe

Optimizing the design of timber components under decay and climate variations

International audienceThe durability of timber structures can be affected by the isolated or combined actions of loading, moisture content, temperature, biological activity, etc. This work focuses on the optimal design of new timber structures subjected to deterioration. Since the deterioration processes and the structural behavior of timber structures are complex, nowadays the deterioration models are not able to account for all influencing factors. Consequently, this study is based on an empirical model that was derived based in-lab experimental studies for the decay growth of brown rot in pine sapwood under variant climate conditions. Such a model is divided into two processes: (i) activation process and (ii) mass loss process. On the other hand, there are significant uncertainties involved in the problem. The uncertainties inherent to materials properties, models and climate are considered throughout a time-dependent reliability based-design optimization (TD-RBDO) approach. The TD-RBDO aims to ensure a target reliability level during the operational life. This approach is applied to design optimization of a new timber component subjected to different French climates. The performance of the optimized solution is compared with a traditional cross-section designed according to the Eurocode 5 in terms of safety. The overall results indicate that an optimized solution ensures a target reliability level during the whole structural lifetime

Stochastic analysis of mixed mode fracture in timber material using polynomial chaos expansion

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Numerical fracture analysis coupling thermo-hygro mechanical and viscoelastic behaviour

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