Papers by Keyword: Flexion

Abstract: This paper presents results of the application of Ti/ta-C films to micro drilling operation for machining. Tetrahedral amorphous carbon (ta-C) films were successfully deposited on WC-Co substrates by a filtered cathodic vacuum arc (FCVA) system. The mechanical and flexion properties of Ti/ta-C films were systematically investigated. The experimental results show that the Ti/ta-C coated micro drills have the excellent microhardness, adhesion and flexion properties and represent the optimal coatings for micro drilling applications. The role of the Ti –sublayer on a sintered powder tungsten carbide substrate is not only limited by the adhesion improvement, but it is mainly used to neutralise the grain boundary microcracks on a surface. The results of drilling tests carried out on PCB boards showed that the durability and drilling efficiency of tools coated by Ti/ta-C films are significantly higher than that of uncoated ones.

Abstract: The purpose of the present preliminary investigation is to characterize the vibration signal between normal and symptomatic knee joint. Accelerometers were attached to the medial and lateral retinaculum of dominant knee to acquire the vibration signal induced during flexion and extension of leg. Signals were compared in time and frequency domain and statistical analysis were performed using mean, variance, standard deviation, skewness and kurtosis. The results show that the frequency range for the symptomatic VAG signal is higher than the normal. The results confirm that the proposed approach is indeed feasible for the non-invasive diagnosis of knee pathology disorders.

Abstract: The flexion solicitation induces in a bent beam a non-uniform stress field. The problem becomes more challenging when the material has a complex behavior, because the material may have different response from one area to another according to the local stress state. In the present work, it is considered, a six parameters rheological model to simulate the behavior of an elastoviscoplastic material. The mathematical law of the behavior is established; thereafter one must determine the beam bending curvature which is an essential and capital parameter for the flexion. Indeed, the bending curvature allows knowing the stress field in the beam. In viscoelastic step, the curvature is obtained by an analytical integration. While in the elastoviscoplastic step, two zones of different behaviors coexist which are namely viscoelastic and elastoviscoplastic, then a numerical integration is required. The numerical integration is achieved, and then the stress field is obtained through the beam and over the time.

Abstract: Most stroke patients who have lost the ability to use their fingers do not recover the functions of the fingers in their activity of daily living (ADL). This paper presents a novel approach in finger rehabilitation for acute paralysed stroke survivors. Based on repetitive exercise concept, the device is designed to provide support for fingers to do flexion and extension movements according to the patients range of motion. A conceptual design of the device is proposed after considering the current mechanism and control from similar current devices published and commercialised. A comparison between 4 existing main working mechanisms: (1) Pneumatic Cylinders, (2) Artificial Rubber Muscles, (3) Linkage Mechanism, (4) Cable-Driven Mechanism is also provided in this paper. The key for designing the device is home-based practice, easy to use and affordable. Further investigation and experiments on the proposed: Cable Actuated Finger Exoskeleton (CAFEx) are currently still in progress.

Abstract: We present in this study a creep behavior in flexure of a hybrid composite consisting of a polyester matrix containing methyl methacrylate reinforced by two bidirectional fabrics. The first one is made with E-glass fibers and the second one is made of a knitted polyamide 66. The mass fractions are 13% for the glass fabric and 9% for the polyamide fabric. The specimens, of dimensions (L = 60, l = 15 and h = 2.3 mm) containing 06 alternating layers (2P/2V/2P) were fabricated by using the vacuum bag molding method. Bending tests performed at different temperatures allowed us first to determine the load levels for the creep tests. Creep tests at different loads (5 to 43 MPa) and different temperatures (23 ° to 80 ° C) show a noticeable increase of creep deformation for both tests under the same load and different temperatures just as those carried out at different loads under the same temperature. The initial deformation varies significantly with the load but very little with temperature. The application of the Findley model shows good correlation with experimental results. Model parameters were identified. Creep deformation satisfies the principle of superposition time-temperature-stress (TTSSP). Findley's model has subsequently been coupled with the principle of superposition of time-temperature-stress to plot master curves at different stresses and temperatures; this enables prediction of creep deformation in the long term.

Abstract: A model for the bending and twisting deformation of the giant magnetostrictive cantilever is established in the framework of the principle of minimal free energy and four-parameter bending regime. The angular and magnitude dependence of the torsion and flexion response on the external field was discussed for cantilever beam. The torsion behavior of the cantilever is very sensitive to the external field and shows a hysteresis. Furthermore, the torsion hysteresis of the cantilever calculated by our model qualitatively agrees with recent experimental result, which suggests that our model is effective in describing the cantilever system with magnetic anisotropy.