28 research outputs found
Dispositivo sensorizzato di fissaggio di presa per arrampicata sportiva dotato di sensore di forza triassiale
No full textThe present invention relates generally to the field of sports equipment, and more specifically to the field of climbing.
The present invention has the object to provide a device for fastening climbing holds for sport climbing provided with a triaxial load cell. Among other possible areas of application of the present invention, in addition to training and competitions of sport climbing, there are functional recovery and psychomotricity
3D Printed Low Noise Nozzle: Design and Experimental Tests
No full textThe present paper focuses on the design of a nozzle needed for generating
impulsive air shots with the aim of moving objects. These objects are caps,
moving from a rotating cylinder to the bottle’s neck, inserted on an automatic
machine for bottle secondary sealing. The aim is the reduction of the noise generated
by the air shots, with the creation of an innovative nozzle which keeps the
same main dimension of the currently used one, but changes the inner geometry.
The new shape is obtained by a wide investigation on some existing design, found
in literature, on patents and theoretical studies. The 3D model has been created
on the software Autocad Inventor and then a first prototype has been 3D printed.
Moreover the new nozzle and a commercial one have been tested, comparing their
sound pressure in different conditions. In the end, the new nozzle is proved to be
less noisy then the actual one, given the same flow rate
A new pneumatic pad controlled by means of an integrated proportional valve
No full textAerostatic air bearings have the advantages of supporting loads with no friction and wear and for this feature they are extensively adopted in metrology as they allow very precise motion. The possibility of integrating an active component increases the performance of the aerostatic pads, which can be designed in order to obtain an infinite stiffness or to improve stability. In [1, 2] the authors developed a prototype of active pad controlled by means of digital valves and Arduino board. A shortcoming of this prototype was a small amplitude oscillation of the pad supply pressure due to the opening and closing of the digital valve. In order to overcome this problem a new prototype was designed making use of a proportional valve. This paper shows the first experimental tests together with the numerical model
Innovative force sensor for indoor climbing holds – real-time measurements and data processing, design and validation
No full textIn this article, a system to measure the evolution of load in time and space during indoor climbing is described. The system is based on a set of dedicated multiaxial load cells, which measure the load on each hold of an indoor climbing wall. When the climber hangs on a hold, the load signal is read and sent to a digital acquisition and processing system. Sensor design allows for measurement of the force components applied to the climbing holds, regardless of the application point of the force on the hold. Local deformations were measured through strain gauges. Based on the electrical configuration of the strain gauges, the values of the applied forces can be computed, making the contributions to the deformation due to bending moments and torsion negligible. The sensor was designed, assuming a maximum applicable load of 200 kg without plastic deformation. The design process was based on both analytical and finite element method analyses. An experimental calibration and testing campaign was performed to validate the sensor design
Three-Fingered Gripper with Flexure Hinges Actuated by Shape Memory Alloy Wires
No full textA three-fingered gripper with flexure hinges actuated by shape memory alloy (SMA) wires was designed and prototyped. The aim of the work was the manipulation of small, almost cylindrical objects, e.g. test tubes, by a device having small overall dimensions. A parametric study of four different, but similar, fingers was conducted with the aim of obtaining a solution with a good amplification ratio and a gripping force almost constant during closure. The use of flexure hinges simplifies the design, but limits the finger range of motion. Moreover, it was possible to find a configuration with sufficient work space. Once the finger geometry was defined, the whole hand was then designed with the aim of producing a compact hand contained in a cylindrical volume (d 65 x h 65 mm), and the first prototype was built. Preliminary tests demonstrated its good dimensioning and the success of some technological solutions. The experimental transmission ratio was almost the same as the theoretical one. Some drawbacks have been highlighted, such as a reduced range of motion and incomplete backstroke; future studies will deal with them
Similarities on the permissive role of tissue oxygenation on compression- and contraction-induced hyperaemia
No full textPreliminary design of eddy current brake to improve sustainable mobility
No full textIn recent years, the need to reduce CO2 emissions has developed a change in the transport sector. E-mobility is emerging as a zero-emissions way of travel, but not only the combustion engine produces emission. In fact, a significant part of the vehicle's total pollution is produced by tires and conventional brakes. The eddy current brake is a possible alternative to the well-known mechanical brake to obtain zero-emissions braking with low maintenance. This type of brake converts the vehicle's kinetic energy into thermal energy through the magnetic generation of the eddy currents, which generate Lorentz braking forces. This paper proposes a preliminary design of a zero-emission eddy current brake with a first geometry variation to increase the brake performance, that has been evaluated with an analytical approach and EMS by EMWorks, a 3D finite element method magnetic software able to calculate brake torque and electromagnetic effects
Design of a new pressure regulator with electronic control: Friction forces analysis
No full textThe paper investigates the friction forces developed between the sliding members of a proportional pressure regulator with a power stage consisting of a poppet-type pressure reducer driven by a piston, and a pilot stage with two MATRIX high frequency digital monostable 2-way valves controlled by the PWM technique. Carried out using a specially developed test bench, the investigation identified lubricants and seal geometries that minimize friction forces. Effects of different greases and seal geometries were evaluated and different solutions were compared
One-dimensional experimental mechanical characterisation of porcine aortic root wall
No full textThe human aortic valve, in cases of disease, can be substituted with a stentless biological prosthesis that is made of both porcine aortic root and leaflets. In particular, the aortic root plays a very important part in the opening mechanics of the valve. Therefore, to understand the behaviour of the prosthesis, a knowledge of the mechanical characteristics of each element constituting the system is useful. For a structural and mechanical characterisation of the porcine aortic root wall tissue, specific measuring devices are made. A uni-axial tensile apparatus, operating in a temperature-controlled saline bath, is equipped with special pneumatic clamps. A test rig for the measurement of the specimen cross-sectional area is developed. To determine the porcine aortic root wall mechanical properties, 189 tensile tests are carried out. Specimens of both natural and chemically fixed tissue are used to consider the conditions of both natural valves and prostheses. Tensile tests are carried out on both axial and circumferential specimens taken from 12 areas of one-sixth of the entire aortic root, with the aim of identifying the anisotropic and non-homogeneous behaviour of the tissue. The behavior changes considerably depending on the direction in which the specimen is strained, the chemical treatment and the zone from which it has been taken. The paper presents the stress-strain characteristics of fresh and fixed tissue in all zones of the aortic wall, both in circumferential and axial directions
