Imola, Italy
Imola, Italy

Time filter

Source Type

Tovo R.,University of Ferrara | Lazzarin P.,University of Padua | Berto F.,University of Padua | Cova M.,Sacmi Imola Science | Maggiolini E.,University of Ferrara
Theoretical and Applied Fracture Mechanics | Year: 2014

The paper presents new experimental multiaxial fatigue data on cast iron. Several sets of specimens, taken from a real large component, have been tested under uniaxial and biaxial, tensile and torsional loading; in-phase and out-of-phase combined loadings have also been considered. The obtained results have been compared with similar experimental data taken from the literature, and the tested material has shown high sensibility to the mean value of shear stress under torsional loading, as well as dependence on the mean value of tensile stress under tensile loading. The most suitable fatigue criterion should be related to the larger principal stress variation. The materials show an unusual sensibility to the out-phase loading. © 2014 Elsevier Ltd.


Cova M.,University of Ferrara | Nanni M.,SACMI Imola Science | Tovo R.,University of Ferrara
Procedia Engineering | Year: 2014

Fatigue strength is known to decrease with increasing dimension of the component. This is due to a technological size effect, related to the production process, and to a geometrical size effect, due to a higher probability of finding a large defect. To investigate the latter, an heavy-walled component made of Ductile Cast Iron (DCI) has been trepanned and a fatigue test plan has been carried out using 4 different specimen geometries. An attempt has been made to relate the resulting fatigue strength using a weakest-link approach based on the effective volumes and surfaces. This approach seems to work well only in cases of different specimen's lengths. Some of the fracture surfaces were analyzed by means of SEM and the initiating defects were identified and measured. An approach in which the defects population can be randomly distributed in the specimen has been tried. Virtual fatigue tests have been carried out by considering pure propagation of the worst defect. The resulting fatigue curves showed that this approach is promising but needs further description of the initiation phase. © 2014 The Authors. Published by Elsevier Ltd.


Bosi F.,University of Trento | Piccolroaz A.,University of Trento | Gei M.,University of Trento | Corso F.D.,University of Trento | And 2 more authors.
Journal of the European Ceramic Society | Year: 2014

Mechanical experiments have been designed and performed to investigate the elasto-plastic behaviour of green bodies formed from an aluminum silicate spray dried powder used for tiles production. Experiments have been executed on samples obtained from cold compaction into a cylindrical mould and include: uniaxial strain, equi-biaxial flexure and high-pressure triaxial compression/extension tests. Two types of powders have been used to realize the green body samples, differing in the values of water content, which have been taken equal to those usually employed in the industrial forming of traditional ceramics. Yielding of the green body during compaction has been characterized in terms of yield surface shape, failure envelope, and evolution of cohesion and void ratio with the forming pressure, confirming the validity of previously proposed constitutive models for dense materials obtained through cold compaction of granulates. © 2013 Elsevier Ltd.


Gualtieri A.F.,University of Modena and Reggio Emilia | Riva V.,University of Modena and Reggio Emilia | Bresciani A.,SACMI IMOLA Science | Maretti S.,SACMI IMOLA Science | And 2 more authors.
Journal of Applied Crystallography | Year: 2014

For the first time, this work inspects the accuracy of quantitative phase analysis of both crystalline and amorphous components of stoneware tiles and bricks. A number of variables were considered: the nature of the internal standard, experimental conditions and counting statistics. The so-called G-factor method has also been applied. The results of the X-ray powder diffraction analysis have been compared with the results obtained with optical microscopy and image analysis. Only the mixtures spiked with corundum and silicon yielded accurate weight estimates of the amorphous fraction, whereas the use of highly X-ray absorbing internal standards (such as fluorite, rutile and zincite) resulted in gross underestimations. In fact, microabsorption effects are found to drastically reduce the accuracy of the results when standards with linear X-ray absorption coefficients higher than 100 cm-1 are employed. It was found that very low counting statistics reduced the calculated amorphous fractions in both bricks and stoneware tiles owing to partial masking of the major peak of the internal standard, namely corundum. The application of the G-factor method to the systems investigated was also evaluated. The results are poorer than those obtained using the internal standard. © 2014 International Union of Crystallography.


Collini L.,University of Parma | Pirondi A.,University of Parma | Bianchi R.,University of Parma | Cova M.,Sacmi Imola Science | Milella P.P.,PPM srl
Procedia Engineering | Year: 2011

In this work the fatigue behaviour of a ferritic ductile iron is experimentally studied on a set of specimens extracted from heavy-duty tile press frames. Specimens are non-standard, with a gage rectangular volume 35mm-wide, 3mm-thick and 160mm-long in order to maximise the volume of material subject to fatigue and the surface/volume ratio, compatibly with testing device in use (Amsler FP 422 axial resonant testing machine), and therefore to promote the crack initiation from a defect. A classical staircase methodology is adopted for the fatigue test. Fracture surfaces are examined post-failure, looking for initiation sites and related features. The fatigue crack propagation is then simulated using FE analysis with the Virtual Crack Closure Technique, starting from the experimentally detected initiation sites and cast defect dimension. In this way, it should be possible to assess whether the fatigue strength of such specimens (and, in turn of large castings) is dominated by the crack propagation phase. © 2011 Published by Elsevier Ltd.


Cova M.,University of Ferrara | Nanni M.,SACMI Imola Science | Tovo R.,University of Ferrara
MATEC Web of Conferences | Year: 2014

Fatigue strength is known to decrease with increasing dimension of the component. This is due to a technological size effect, related to the production process, and to a geometrical size effect, due to a higher probability of finding a large defect. To investigate the latter, an heavy-walled component made of Ductile Cast Iron (DCI) has been trepanned and a fatigue test plan has been carried out using 4 different specimen geometries. An attempt has been made to relate the resulting fatigue strength using a weakest-link approach based on the effective volumes and surfaces. This approach seems to work well only in cases of different specimen's lengths. Some of the fracture surfaces were analyzed by means of SEM and the initiating defects were identified and measured. An approach in which the defects population can be randomly distributed in the specimen has been tried. Virtual fatigue tests have been carried out by considering pure propagation of the worst defect. The resulting fatigue curves showed that this approach is promising but needs further description of the initiation phase. © Owned by the authors, published by EDP Sciences, 2014.


Cova M.,University of Ferrara | Nanni M.,SACMI Imola Science | Tovo R.,University of Ferrara
MATEC Web of Conferences | Year: 2014

The definition of the relationship between probability, fatigue stress and cycles to failure is of great importance, especially in applications which requires very low probability of failure (e.g. Pf=0.1%). In this paper a new formulation is presented, which allows to separately consider the probability of the endurance and the probability of existence of the initiating defect. This approach is then compared to a number of known models. For this purpose, the proprietary results of 8 fatigue test sets, each with at least 24 data points, have been analyzed. A ranking of goodness-of-fit based on the Relative Likelihood can be used to choose the best distribution within each model, but unfortunately cannot be used to compare different models. The conclusions were: 1- the better description of the HCF strength, in terms of performance and robustness, were obtained by the 2-p Weibull distribution; 2- the choice of the model has a great influence in the estimate of the low probability quantiles, but it still subjective and a definitive answer cannot be given after this benchmark; 3- the strength of the proposed model is its flexibility. © Owned by the authors, published by EDP Sciences, 2014.


Patent
Sacmi Imola Science | Date: 2013-03-18

An apparatus for manufacturing plastic preforms, comprising a rotating carousel forming device for plastic preforms and movement elements adapted to pick up the preforms from the rotating carousel forming device; the movement elements are associated with a supporting structure for a plurality of shaping receptacles, which are mutually spaced and movable along a transfer path, the shaping receptacles being adapted to receive a respective preform directly from the rotating carousel forming device and at an angular pick-up portion which is defined along the circular movement trajectory of the preforms on the rotating carousel forming device.


Patent
Sacmi Imola Science | Date: 2014-07-16

An apparatus for printing closure bodies of containers having, a transfer device that is associated in input with a feeder of closure bodies to be printed and in output with an unloader of printed closure bodies. The transfer device defines seats for a respective closure body to be printed which are provided with at least one resting region for at least one abutment portion that is defined on the outer lateral surface of the respective closure body. The seats are mutually spaced at preset distances and movable along a transfer trajectory. The apparatus includes a device for digital printing of the closure bodies to be printed which is arranged along the transfer trajectory).


Patent
Sacmi Imola Science | Date: 2014-07-23

A plant for manufacturing and printing cup-shaped bodies having an apparatus for manufacturing cup-shaped bodies that includes at least one portion made of plastics and a device for positioning the cup-shaped bodies manufactured by the apparatus on a transfer device that can move along a longitudinal transfer direction. The cup-shaped bodies rest with their lower edge on a resting surface that is defined by the transfer device with its concavity directed toward the resting surface. The plant includes, along the extension of the longitudinal transfer direction, a device for the digital printing of the cup-shaped bodies, and a component for controlling the position of the top edge of the cup-shaped bodies on the resting surface, the component being connected to the digital printing device.

Loading SACMI Imola Science collaborators
Loading SACMI Imola Science collaborators