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In tribosystems that include contact with a flexible body, friction-induced vibration may be present. Dimensionlessanalysis coupled with numerical manipulation was employed to model the discontinuity between thestatic and kinetic behaviour of the friction. The present paper discusses the nature of stick-slip between a humanfingertip and standard printing paper, intending to describe the theoretical stability conditions of movement. Theamplitude of the stick-slip phenomenon is analised as a function of the human skin’s rheological and tribologicalproperties, the system’s rigidity, and the sliding contact velocity.

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In this research, a numerical investigation has been conducted to analyze the dynamic load of the composite structure. The composite structure was solved and analyzed using the static structure tool. There is a physical model that has been imported and meshes have been done accordingly. Shear stress, von-mises stress, and total deformation are all considered as part of the analysis. Using finite elements to simulate the composite structure and response to the applied loads. Because dynamic loads were regularly applied, frequency response was examined. In this study after verification of this computer simulation with experimental results and the results showed it was confidence 95 %. This percentage confidence allows proceeding numerical analysis. Deformation of the entire structure has been computed and found to be 10 mm, which is the maximum amount of overall deformation that can be caused by the applied load, In the Y-axis, a dynamic load was applied. The imposed dynamic load has been studied numerically and interpreted in terms of shear stresses.

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In this paper, the numerical simulation of the mechanical performance of a composite prosthetic keel structure under static load has been explored, and the findings of this inquiry have been included. The prosthetic keel is constructed from an epoxy and glass fiber composite, 3 percent weight (MWCNTs with SiC), and a carbon nanotube, which are utilized in conjunction with other materials to create the structure. The force that is applied in this example is 1,000 N, and it is applied in accordance with the boundary condition that has been previously established in this case. The ANSYS modeling software package was used to create the prosthetic keel model, which was meshed and created. Because of the total deformation, the fundamental simulation results of the prosthetic keel model have been converged in line with the total deformation, which was used as a reference to determine the total deformation. The major outcome of the current numerical analysis has been successfully validated by considering the findings of the earlier experimental study

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The present paper investigates experimentally effect of applied load and different velocity on the coefficient of friction between two interacting surfaces (human skin and Ultra-highmolecular- weight polyethylene (UHMW- polyethylene) at static and dynamic friction. It is possible to conclude specific point based on the above practical part and frictional analysis of this investigation as the most important mechanical phenomenon was creep has been observed a stick time interval where the static friction force is significantly increased during this stroke. The analytical model for stick-slip of skin and UHMWPE is proposed. The difference between static and kinetic friction defines the amplitude of stick-slip phenomena. The contact pressure, the sliding velocity, and rigidity of system determine the stability conditions of the movement between skin and UHMWPE. Experiments were carried out by developing a device (friction measurement). Variations of friction coefficient during the time at different normal load 4.6 and 9.2 N and low sliding velocity 4, 5, 6 and 7 mm/min were experimentally investigated. The results showed that the friction coefficient varied with the normal load and low sliding velocity.

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In the current work, the influences of titanium oxide (TO) on nanocomposites using epoxy (EP) resin have been investigated. EP resin was added to various contents in terms of volume ofTO(6%). Based on the casting method, the TO-EP nanocomposites were prepared. Mechanical properties in terms of tensile, impact and hardness properties exhibited improvements in the mechanical results of the TO-EP nanocomposites. The experimental results exhibited that the enhancement in the tensile strength, impact, and hardness was found to be 14 MPa, 40.1 J/mm2 and 228.9 HV, respectively. Moreover, the effect of the strength has decreased compared with pointing to brittleness that increased the TO-EP nanocomposites. Field emission scanning electron microscopy (FESEM) analysis was used to performa microstructure analysis which in turn revealed how TO obstruction the cracks propagation in the nanocomposites. The interface between the TO and the EP nanocomposites was observed using the FESEM images. The results highlighted that the TO-EP nanocomposites can be used a wide range of industrial applications such as biomedical application.

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This paper is an experimental investigation on the interaction between the human finger and polytetrafluoroethylene (PTFE) with regards to friction. Three male Asian volunteers aged 24, 52 and 66 were asked to participate. The experimental setup consisted on a circle tipped probe being placed in contact with the ring finger of the volunteers and dragged over the surface of the finger with an applied load of (1-12) N. The friction phenomenon was evaluated in both dry and wet conditions using the CETR

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Nonlinear elastic models have been widely used to describe the mechanical behaviour of complex materials such as skin. The subject of skin modelling is fairly new and of great importance to fields such as robotics and the development of skin-like materials to orthopaedics and prosthetics. The present article serves to add to the findings of previous authors and present experimental values gathered using the “Stick-Slip Experimental Stand” within the Machine Elements and Tribology Department on the tribological aspects regarding friction at very low speeds. The scope of this article is to evaluate the static and kinetic friction coefficients of the human skin in contact with different materials. A total of 5 different materials were tested to find the static and kinetic friction coefficient. The tested materials were steel, bronze, and 3 types of materials found on the inside of working gloves in direct contact with human skin: leather (bovine origin) and 2 types of textiles (cotton and nylon). All tests were performed at 1.8 mm/min, with an initial load of 7.5 Newton and a test time of 1000 seconds. The total distance evaluated was 9.25 mm.

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The twist static friction and the creep behavior of bovine skin in contact with Ultra High Molecular Weight Polyethylene (UHMWPE) indenters were studied by employing both theoretical and experimental methods. Loads (1 and 2 N) were applied to bovine skin using different indenter shapes. Moreover, the creep area and the coefficient of static friction were also discussed and analysed for different time durations. The experimental and theoretical results showed that the Voight-Kelvin rheological model could be used to represent the mechanical response of the cattle skin. As a conclusion, the creep parameter and the coefficient of static friction of bovine skin increased in time. For the circular indenter, the creep area was higher than in the case of the other shapes. The study provides a base for more investigations on cattle skin behavior in order to be utilized on a rigid support (UHMWPE) as a new solution for “exoprosthesis support".

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Human skin considered as an important organ in the human body since it works as a barrier between outside environment and the internal components, also it covers approximately two squared meter in total area and around 18% of human weight in adult. In case of lower limb amputation, the stump will be in direct and continuous touch with textile material in between the polymeric socket and stump itself, so to avoid skin injuries or ulcers which are causes if bad contact conditions occur for long time duration. In present work coefficient of friction of different textiles with in-vivo human skin for both male and female at the stump region are investigated, this specific contact area is influenced by many factors such as skin humidity, nature of the employed textile itself, temperature, and other factors. This paper will clarify how coefficient of friction varies together with different textile to provide comfortable ambient at this sensitive region.

ملخص البحث :

The viscoelastic behavior of ex-vivo cow skin was experimentally studied by applied load from different indenter types (circle, square and triangle, all types have the same area) for different times (10 sec, 30 sec, and 60 sec). The viscoelastic tests were carried out using a UMT series (UMT-II, CETR Corporation). The experimental results collected at different operating conditions showed that the cow skin has a higher reaction against the triangle indenter compared to the other shapes. Whereas the hysteresis of cow skin was lower at low applied load time and it's increased when the time increased.