Biomedical engineering - Bioingegneria
Amateur football pitches: Mechanical properties of the natural ground and of different artificial turf infills and their biomechanical implications.Scritto da Zanetti Elisabetta Mercoledì, 19 Marzo 2014 11:02
This work analyses blunt abdominal trauma produced by driver-handlebar collision, in low speed two-wheel accidents. A simplified dynamic model is introduced, whose parameters have been estimated on the basis of cadaver tests. This model allows calculating the peak impact force and the abdominal penetration depth; therefore the likelihood of occurrence of serious injuries can be estimated for different masses of contacting bodies and different speeds. Results have been checked against literature data and true-accident reports. Numerical simulations demonstrate that serious injuries (AIS>3) can occur even at low speeds (<20km/h), therefore the design of protective clothing is recommendable. The model can allow both the analysis of true accident data and the virtual testing of protective equipment in the conceptual design phase.
A new device for 3D oral scanning has been designed and tested: it is a two channel PTOF (pulsed time-of-flight) laser scanner, designed for dental and industrial applications in the measurement range of zero to a few centimetres. The application on short distances (0–10 cm) has entailed the improvement of performance parameters such as single shot precision, average precision and walk error up to mm-level and to µm-level respectively.
The single-shot precision (σ-value) has resulted to range from 43 to 63 ps (9–10 mm), having considered the measurement range (6.5–10 mm) corresponding to 1–2 V signal; this result agrees well with estimates made from simulations. The average precision has resulted to be dependent on the number of measurements and can reach a value equal to ±25 µm, whenever the measurements frequency is sufficiently high. For example, if the required scanning speed is 1000 points/s and the required average precision is ±25 µm, then a pulses frequency of 30–50 MHz is needed, considering signal amplitude varying between 1–2 V.
On the whole, the performance of this new device, based on PTOF has proven to be adequate to its employment in the field of restorative dentistry.
Set up of a prescreening tool for vehicle front-end design, allowing numerically forecasting of the results of EC directive tests, with reference to pedestrian lower leg impact.
A numerical legform model has been developed and certified according to EC directive. The frontal end of the vehicle has been simulated through a lumped-parameters model, having considered the predesign stage when the target overall behavior is being established. The stiffness behaviors of the bumper and of the spoiler have been estimated by means of more detailed numerical models.
A parametric analysis has been performed to outline the effects of bumper and spoiler stiffness, bumper vertical height, and the longitudinal distance between the spoiler and the bumper.
An analytical model has been introduced to predict tibial acceleration, knee shear displacement, and knee lateral bending, given the bumper and spoiler characteristics as input