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Bensghaier A.,University of Monastir | Romdhane L.,Laboratoire Of Genie Mecanique Lgm | Benouezdou F.,University of Versailles
Comptes Rendus - Mecanique | Year: 2012

This work is focused on the determination of the thumb and the index finger muscle tensions in a tip pinch task. A biomechanical model of the musculoskeletal system of the thumb and the index finger is developed. Due to the assumptions made in carrying out the biomechanical model, the formulated force analysis problem is indeterminate leading to an infinite number of solutions. Thus, constrained single and multi-objective optimization methodologies are used in order to explore the muscular redundancy and to predict optimal muscle tension distributions. Various models are investigated using the optimization process. The basic criteria to minimize are the sum of the muscle stresses, the sum of individual muscle tensions and the maximum muscle stress. The multi-objective optimization is solved using a Pareto genetic algorithm to obtain non-dominated solutions, defined as the set of optimal distributions of muscle tensions. The results show the advantage of the multi-objective formulation over the single objective one. The obtained solutions are compared to those available in the literature demonstrating the effectiveness of our approach in the analysis of the fingers musculoskeletal systems when predicting muscle tensions. © 2012 Académie des sciences.

Sghaier A.B.,University of Monastir | Romdhane L.,Laboratoire Of Genie Mecanique Lgm | Ouezdou F.B.,University of Versailles
Computer Methods in Biomechanics and Biomedical Engineering | Year: 2012

This work displayed the force capabilities of the musculoskeletal system of the forefinger under external loading. Different states of normal and pathological fingers are studied. We evaluated the impact of losing musculo-tendon unit strength capacities in terms of maximal output fingertip force and tendon tensions distribution. A biomechanical model for a static force analysis is developed through anatomical and kinematic studies. An optimisation approach is then used to determine tendon tension distribution when performing an isometric task. Furthermore, pathological fingers with common cases of injured flexors and extensors are analysed. The method of simulation for forefinger abnormities is described. Furthermore, the simulation results are interpreted. © 2012 Copyright Taylor and Francis Group, LLC.

Sghaier A.B.,University of Monastir | Romdhane L.,Laboratoire Of Genie Mecanique Lgm | Ouezdou F.B.,University of Versailles
International Review of Mechanical Engineering | Year: 2010

The objective of this work is to estimate tendon forces and fingertip strength during the generation of functional static forces for the normal, the pathological and the surgical reconstructed fingers. A 3D biomechanical model for the static force analysis was developed. This model takes into account all the tendons in the fingers and their related moment arms. Optimization approaches are used to solve muscular redundancy, to obtain a tendon forces distribution and to quantify optimal pinch strength. The model is compared to other previous published works. For the repaired hands, the outcomes of two common tendon transfers are explored. The Br-FPL transfer used to restore the thumb IP joint flexion. The FCU-EDC transfer used to reanimate the index finger extension. © 2010 Praise Worthy Prize S.r.l. - All rights reserved.

Gara S.,Laboratoire Of Recherche Mecanique Appliquee Et Ingenierie Mai | Fredj R.,Laboratoire Of Genie Mecanique Lgm | Naimi S.,Laboratoire Of Genie Mecanique Lgm | Tsoumarev O.,Laboratoire Of Recherche Mecanique Appliquee Et Ingenierie Mai
International Journal of Advanced Manufacturing Technology | Year: 2016

This paper focuses on experimental study of slotting of carbon fiber reinforced plastic (CFRP) laminate (G803/914) with three micrograin carbide knurled tools: fine, medium, and coarse toothings. It highlights the influence of tool geometry and cutting conditions (cutting speed and feed per tooth) on cutting forces and presents the damage that occurs to the composite material in response to mechanical effects. The experiment is made on CNC machine with cutting speed ranging from 80 to 200 m/min and feed per tooth from 0.008 to 0.060 mm/rev/tooth. The data was analyzed in order to establish empirical models showing the dependence of cutting forces on tool geometry and cutting conditions. The results illustrate that feed per tooth is the cutting parameter that presents the highest statistical and physical influence on cutting forces and that knurled tool fine toothings is the suitable tool that produces the least damage to the composite plate. © 2016 Springer-Verlag London

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