Adaptive reduced basis strategy for rare events simulations

International audienceMonte-Carlo methods are well suited to characterize events of which associated probabilities are not too low with respect to the simulation budget. For very seldom observed events, these approaches do not lead to accurate results. Indeed, the number of samples are often insufficient to estimate such low probabilities (at least 10 +2 samples are needed to estimate a probability of 10 − with 10% relative deviation of the Monte-Carlo estimator). Even within the framework of reduced order methods, such as a reduced basis approach, it seems difficult to accurately predict low probability events. In this paper we propose to combine a cross-entropy method with a reduced basis algorithm to compute rare events (failure) probabilities

Requirements for artificial muscles to design robotic fingers

International audienceThis work is part of the ProMain project that concerns the modeling and the design of a soft robotic hand prosthesis, actuated by artificial muscles and controlled with surface Electromyography (EMG) signals. In a first stage, we designed a robotic finger based on the equivalent mechanical model of the human finger. The model takes into account three phalangeal joints, flexion and extension movements are studied. The robotic finger has three Degrees of Freedom (DoF). The finger is designed to be under-actuated and driven by tendons, i.e. only one servo motor actu-ates the whole finger, and the motor is coupled to the finger mechanism through two flexible wires. As the aim is to design a robotic hand prosthesis that uses artificial muscles, we propose and carry out two experiments to characterize the specifications of the actuator. The first experiment measures the pinch force of the human finger, and the second measures the achieved force using our robotic finger and five different servo motors. It allows us to enhance experimental results with the mathematical model of the finger, to identify the requirements of the artificial muscle

Error estimation of stress intensity factors for mixed-mode cracks

This paper presents an a posteriori error estimator for mixed-mode stress intensity factors in plane linear elasticity. A surface integral over an arbitrary crown is used for the separate calculation of the combined mode’s stress intensity factors. The error in the quantity of interest is based on goal-oriented error measures and estimated through an error in the constitutive relation

A posteriori error analysis of a domain decomposition algorithm for unilateral contact problem

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Modeling of composite plates with an arbitrary hole location using the variable separation method

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Towards error bounds of the failure probability of elastic structures using reduced basis models

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Shell finite element based on the Proper Generalized Decomposition for the modeling of cylindrical composite structures.

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Composite beam finite element based on the proper generalized decomposition

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