Fibre-reinforced polymers (FRP) have attracted much interest within many industrial fields where the use of 3D printed molds can provide significant cost and time savings in the production of ...composite tooling. Within this paper, a novel method for the manufacture of complex-shaped FRP parts has been proposed. This paper features a new design of bike saddle, which was manufactured through the use of molds created by fused deposition modeling (FDM), of which two 3D printable materials were selected, polylactic acid (PLA) and acrylonitrile butadiene styrene (ABS), and these molds were then chemically and thermally treated. The novel bike saddles were fabricated using carbon fiber-reinforced polymer (CFRP), by vacuum bag technology and oven curing, utilizing additive manufactured (AM) molds. Following manufacture the molded parts were subjected to a quality inspection, using non-contact three-dimensional (3D) scanning techniques, where the results were then statistically analyzed. The statistically analyzed results state that the main deviations between the CAD model and the manufactured CFRP parts were within the range of ±1 mm. Additionally, the weight of the upper part of the saddles was found to be 42 grams. The novel method is primarily intended to be used for customized products using CFRPs.
Following cardiac surgery, patients experience difficulties with the rehabilitation process, often finding it difficult, and therefore lack the motivation for rehabilitation activities. As the number ...of people aged 65 and over will rise by 207 percent globally by 2050, the need for cardiac rehabilitation will significantly increase, as this is the main population to experience heart problems. To address this challenge, this paper proposes a new robotic exoskeleton concept with 12 DoFs (6 DoFs on each arm), with a symmetrical structure for the upper limbs, to be used in the early rehabilitation of cardiac patients after open-heart surgery. The electromechanical design (geometric, kinematic, and dynamic model), the control architecture, and the VR-based operating module of the robotic exoskeleton are presented. To solve the problem of the high degree of complexity regarding the CardioVR-ReTone kinematic and dynamic model, the iterative algorithm, kinetic energy, and generalized forces were used. The results serve as a complete model of the exoskeleton, from a kinematic and dynamic point of view as well as to the selection of the electric motors, control system, and VR motivation model. The validation of the concept was achieved by evaluating the exoskeleton structure from an ergonomic point of view, emphasizing the movements that will be part of the cardiac rehabilitation.
Three dimensional digitization of cultural heritage resources gains a lot of attention from the European Union and the United Nations, which is clearly revealed in current strategic goals and ...financing perspectives. Existing methodological approaches to 3D scanning in a prevailing number of cases assume that the procedure of scanning is performed in places that are closed to tourists, at least for the time of scanning. However, closing an exhibition for tourists or moving an artifact to be scanned is not always possible. Thanks to the long-term experience of the authors with 3D scanning of cultural heritage, the special procedure was designed for small and medium size objects to overcome difficulties expected in such cases. The procedure has been successfully implemented during 3D scanning of objects exhibited in the Silk Road region (on the territory of modern Uzbekistan), as well as objects being parts of wooden sacral architecture of the Maramures region (in Romania). It was revealed that the proposed procedure was successfully allowed to counteract organizational problems during 3D scanning of heritage objects being under continuous display, and that the achieved results of scanning were nevertheless of good quality.
This paper presents two electromechanical systems used for the overspeed protection of small wind turbines. The actuators have the purpose of rotating the back rudder (tail vane) of the wind turbine ...when the blades are overspeeding. The rudder rotation angle is 90 degrees in order to completely turn the wind turbine blades away from the wind flow direction. The first device is a new limited-angle torque electromechanical actuator consisting of a device with a simplified structure composed of four permanent magnets (two on each side) glued on a rotor mounted between two stator poles built from ordinary rectangular construction pipes and an electronic control unit. The second device is based on a regular stepper motor actuator with a reduction gear and an appropriate control scheme to maximize the energy harvested at high, over-nominal wind speeds. A generic comparison is provided for the proposed solutions.
The paper presents a methodology to create 3D digital and virtual artefacts in the field of archaeology using CAD software solution. The methodology includes the following steps: the digitalization ...process, the digital restoration and the dissemination process within a virtual environment. The resulted 3D digital artefacts have to be created in files formats that are compatible with a large variety of operating systems and hardware configurations such as: computers, graphic tablets and smartphones. The compatibility and portability of these 3D file formats has led to a series of quality related compromises to the 3D models in order to integrate them on in a wide variety of application that are running on different hardware configurations. The paper illustrates multiple virtual reality and augmented reality application that make use of the virtual 3D artefacts that have been generated using this methodology.
Robotic exoskeletons have the potential to enhance the quality of life of patients undergoing cardiac rehabilitation. Recent studies found that the use of such devices was associated with significant ...improvements in physical function, mobility, and overall well-being for individuals recovering from a cardiac event. These improvements were seen across a range of measures, including cardiovascular fitness, muscle strength, and joint range of motion. In addition, the use of robotic exoskeletons may help to accelerate the rehabilitation process, allowing patients to make faster progress towards their goals. This article proposes a new robotic exoskeleton structure with 12 DOFs (6 DOFs on each arm) in a symmetrical construction for upper limbs intended to be used in the early rehabilitation of cardiac patients following open-heart surgery or a major cardiac event. The mathematical modelling and empirical validation of the robotic exoskeleton prototype are described. The matrix exponential algorithm, kinetic energy, and generalized forces were employed to overcome the problem of high complexity regarding the kinematic and dynamic model of the robotic exoskeleton. The robotic exoskeleton prototype was empirically validated by assessing its functionalities in a lab and medical environment.
The fiber reinforced polymers (FRP) represent a group of materials with a very impressive development in the last time. There are used in different applications from aerospace to sports or medicine. ...Carbon fiber reinforced polymer (CFRP) has special properties and tend to replace traditional materials like steel, aluminum alloys or wood. Different procedures were developed to manufacture the CFRP. Autoclave processing can be considered the most important way to obtain the best mechanical properties of this kind of material. In this paper it is presented the autoclave manufacturing process to obtain theCFRP plates. The autoclave polymerization process steps are indicated for the CFRP made of Twill textile prepreg material. The stacking sequence of the layers is 0/90. To determine the mechanical properties of the material tensile test on standardized specimens was employed. The obtained mechanical material’s properties are comparable with steel but its density was reduced 5.5 times.
The paper presents a measuring strategy for a Formula One car using a Coordinate Measuring Machine (CMM) and a 3D laser scanning devices. The measurement procedures outlined the dimensional deviation ...of the CAD model and prototype made of composite material. The authors present two methods for the determination of symmetry for components of a Formula One car based on measuring and 3D scanning.
The polymeric reinforced composite materials (FRP) are a new materials group which have a lot of research reported in the last years. Our paper present the results obtained in case of use FRP for ...manufacturing an electric vehicle front hood in order for lightweight chassis and increase the autonomy. The design stage and 3D modelling of the mould, material design and manufacturing front hood from Carbon Fibber/Epoxy are presented.
Paper by Paul Bere, Calin Neamtu. “Methodology for evaluate the form deviations for formula one nose car” in Volume 4, Issue 2, 148–154/June 2014 doi: 10.2478/s13531-013-0158-x contains an error in ...the author’s affiliation and descriptions of figures. The correct affiliation and descriptions of figures are presented below.
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