Massimiliano Avalle

Metallic foam samples of matrix alloy AlSi7 have been produced and mechanically tested under quasi-static and dynamic load. Model parameters for the Deshpande–Fleck and the ABAQUS ‘crushable foam’ material model were determined covering a density of 0.3–0.8 g/cm. Yield surface determination uses uniaxial hydrostatic compression test results, extended by tensile test results for the latter model. Strain hardening was described on the basis of uniaxial compression by fitting a Rusch model to the experimental data, deriving its parameters as function of density. The predictive capabilities of the parameterised models were evaluated using experimental data gathered for load cases characterised by superimposed uniaxial and hydrostatic compression. Analyses show good agreement between simulation and experiment. Further uniaxial compression tests performed at varying strain rates over 4 orders of magnitude revealed no significant strain rate dependency of material properties and thus qualify the material model parameters determined for crash simulation.

... ceramics Andrea Ventrella • Milena Salvo • Massimiliano Avalle • Monica Ferraris ... Experimental The ceramics are alumina (Al2O3, non-filled dots in Figs. 1, 2, 3, 4) (Bettini Textile, Italy) and chemical vapour deposition silicon carbide (CVD SiC, filled dots in Figs. ...

AbstractThe results of an experimental investigation on epoxy-joined silicon carbide tested in shear mode by four different configurations of torsion test are presented and compared to results obtained by asymmetric four-point bending and four different lap tests in compression. All samples have been joined by an epoxy adhesive (Araldite AV119) which is to be considered as a model brittle joining material chosen to obtain several joined samples in a reasonable time. Advantages and disadvantages of each configuration are discussed and compared to results previously obtained with epoxy-joined Carbon/Carbon composites and ceramics tested with the same methods.

The SubProject 7 “Virtual Testing” [1] of the 7th FP Project APROSYS (Advanced PROtection SYStems) was aimed at development of a complete and consistent methodology for the implementation of the virtual testing of vehicles for safety improvement. Recall that by Virtual Testing we ...

... 95 S9.50 A theoretical approach to the optimization of Hexural stiffness of symmetric laminates Massimiliano Avalle Giovanni Belingardi Mechanical ... REFERENCES 1. Mesquita, L. Kamat, MP, Optimization of stiffened laminated composite plates with frequency constraints. ...

Sommario L'analisi della microstruttura di molti materiali di tipo cellulare può essere effettuata mediante l'utilizzo di tomografie ai raggi X. Questa tecnica consente una visualizzazione tridimensionale di tipo non distruttivo dei materiali esaminati a livello della loro microstruttura cellulare. Nel presente lavoro un provino di schiuma strutturale in lega di alluminio è stato sottoposto ad una prova di compressione uniassiale

... 4. Energy Absorption The crash boxes are the parts of a car body aimed to absorb energy during a frontal crash. ... Acknowledgement The support of Mr. Piero Mauri of Henkel Loctite is gratefully acknowledged for the realization of this work. References ...

ABSTRACT Advanced ceramics appear to be a very important resource for the development of many new technologies (fuel cells, nuclear fusion[[ellipsis]]) and in many manufacturing processes. An important issue in the construction of ceramic components is related to their joining methods. When size and complexity of the components grow, it is impossible to sintherize them in a single monolithic piece. It is necessary to join several parts: apart from mechanical joining systems, the primary solution is to use a material — that acts as adhesive — able to intimately join the two materials. The joining material needs to give sufficient mechanical strength, and to maintain resistance to external actions at high temperatures, as the adherend material is able to. In this paper, some results obtained in the Innovative Materials Laboratory (La.M.In.) of the II Faculty of Engineering of the Politecnico di Torino, will be shown. Since there is no unique method to measure the shear strength of the ceramics joints (the most important is ASTM C1469-00) and lack of agreement on a common test still exists, different testing methods were considered. One of the main difficulties is still to correlate the results from different tests: in fact, in each testing method the sample is subjected to different states of stress, and failure is induced differently. A thorough stress analysis has to be carried, by means of detailed finite elements models.

ABSTRACT The mechanical behaviour of stainless steel AISI 316L based syntactic foams containing either 40/60 vol.% of hollow glass microspheres (S60HS) or 40 vol.% of Fillite cenospheres were investigated. In these materials, the hollow particle shells as third phase besides matrix and voids can provide a strengthening effect with the potential of raising mechanical performance above that of conventional, two phase steel foams. Samples were produced by means of metal powder injection moulding (MIM) and subjected to characterization under compressive load, with special attention dedicated to strain-rate sensitivity. Four strain-rate levels were investigated, covering 6 orders of magnitude from 10-3 to 103 s-1. For the highest, a Hopkinson Bar apparatus was used. The influence of density on strength was determined for samples containing glass microspheres and described by a power law relationship. The foams mechanical strength was found to increase with strain-rate in accordance with the behaviour observed for the reference material without hollow particles. The data were compared with those obtained in a previous work, in which Fe99.7 matrix syntactic foams containing similar levels of glass microspheres were investigated. The higher strength of the AISI 316L materials is associated with differences in matrix properties. Differences in strain-rate dependence of mechanical properties between both materials can be explained qualitatively based on the fcc (AISI 316L) and bcc (Fe99.7) lattice structure. The introduction of Fillite cenospheres induced a further increase of specific strength. Under quasi-static conditions, samples of this type were found to reach the same yield strength as the reference material despite the reduction in density. The significantly lower strength of glass microsphere based AISI 316L foams can be related to the observed microstructures: due to the high processing temperature (1200°C), glass microspheres are destroyed during sintering, their remainders forming glass inclusions, whereas thermally more stable cenospheres remain intact and can thus stabilize the pores. Finally, an empirical strain-rate sensitive model was adopted to reproduce the experimental data: the fitting procedure used to obtain the model parameters was explained and the influence of the strain-rate discussed. The model allows property prediction for additive content and strain-rate levels further to those evaluated experimentally.

Design of modern and future cars will be an ever challenging task, due to the ever growing increase of different requirements and availability of more advanced materials. Well established knowledge on traditional materials (mainly mild steels) is available, but there ...

AbstractBrazilian disk test is here analyzed as a test method to determine the strength of joined ceramics. The test specimen consisted of two silicon carbide half-disks diametrically bonded with a brittle adhesive (Araldite AV119™). Several tests were performed with different angles of the adhesive layer with respect to the diametral line of loading. An elastic finite element analysis is used to determine the maximum shear stress and the normal compressive stress within the joint. Assuming a failure criterion based on a shear stress condition, this procedure allows evaluating the shear strength of the epoxy adhesive.

Search. Advanced Search Within current journal Entire site. Home > List of Issues > Table of Contents > Bi-Material Joining for Car Body Structures: Experimental and Numerical Analysis. ... Bi-Material Joining for Car Body Structures: Experimental and Numerical Analysis. ...