Marco Rossi

Bio: Marco Rossi is an academic researcher from Marche Polytechnic University. The author has contributed to research in topics: Digital image correlation & Necking. The author has an hindex of 20, co-authored 72 publications receiving 1138 citations. Previous affiliations of Marco Rossi include Arts et Métiers ParisTech & ParisTech.

The Virtual Fields Method

Abstract: The Virtual Fields Method (VFM) is one of the techniques developed to identify the parameters governing constitutive equations, the experimental data processed for this purpose being displacement or strain fields. It will be shown in this chapter that one of its main advantages is the fact that, in several cases, the sought parameters can be directly found from the measurements, without the need of calculating the stress with a numerical tool such as a finite element programme.

Effect of DIC Spatial Resolution, Noise and Interpolation Error on Identification Results with the VFM

Abstract: The use of experimental tests that involve full-field measurements to characterize mechanical material properties is becoming more widespread within the engineering community. In particular digital image correlation (DIC) on white light speckles is one of the most used tools, thanks to the relatively low cost of the equipment and the availability of dedicated software. Nonetheless the impact of measurement errors on the identified parameters is still not completely understood. To this purpose, in this paper, a simulator able to numerically simulate an experimental test, which involves DIC is presented. The chosen test is the Unnotched Iosipescu test used to identify the orthotropic elastic parameters of composites. Synthetic images are generated and then analysed by DIC. Eventually the obtained strain maps are used to identify the elastic parameters with the Virtual Fields Method (VFM). The numerical errors propagating through the simulation procedure are carefully characterized. Besides, the simulator is used to compare the performances of DIC and the grid method in the identification process with the VFM. Finally, the influence of DIC settings on the identification error is studied as a function of the camera digital noise level, in order to find the best testing configuration.

Identification of plastic constitutive parameters at large deformations from three dimensional displacement fields

Abstract: The aim of this paper is to provide a general procedure to extract the constitutive parameters of a plasticity model starting from displacement measurements and using the Virtual Fields Method. This is a classical inverse problem which has been already investigated in the literature, however several new features are developed here. First of all the procedure applies to a general three-dimensional displacement field which leads to large plastic deformations, no assumptions are made such as plane stress or plane strain although only pressure-independent plasticity is considered. Moreover the equilibrium equation is written in terms of the deviatoric stress tensor that can be directly computed from the strain field without iterations. Thanks to this, the identification routine is much faster compared to other inverse methods such as finite element updating. The proposed method can be a valid tool to study complex phenomena which involve severe plastic deformation and where the state of stress is completely triaxial, e.g. strain localization or necking occurrence. The procedure has been validated using a three dimensional displacement field obtained from a simulated experiment. The main potentialities as well as a first sensitivity study on the influence of measurement errors are illustrated.

Non-invasive blood component analyzer

Abstract: A non-invasive blood component analyzer using spectrophotometry, with systole/diastole corrections for tissue absorbance, and with built-in monitoring of light path length to allow its accurate use in subjects with widely varying finger size and/or varying pulse amplitude. Blood components that are able to be analyzed include oxy-hemoglobin, total hemoglobin, bilirubin, glucose, hormone levels and a variety of drugs.

Liquid pumping mechanisms for peritoneal dialysis systems employing fluid pressure

Abstract: Pumping mechanisms for performing peritoneal dialysis and the like employ a pumping mechanism comprising a diaphragm (59) that operate in response to applied fluid pressure. Flexible tubing is attached to the pumping mechanism for carrying liquid to and from the patient's peritoneal cavity. An actuating station for pumping mechanism receives the pumping mechanism and attached tubing. A pressure transfer element (104) conveys fluid pressure to the diaphragm (59) for moving liquid through the cassette. An occluder element (138, 144) contacts and crimps closed the tubing attached to the cassette. A first reservoir (128) inflates with positive fluid pressure for contacting the pressure transfer element (104) to hold it in operative contact against the diaphragm (59). A second reservoir inflates with positive fluid pressure for contacting the occluding element (138, 144) to hold it away from crimping contact with the tubing. At least one of the first (128) and second (152) reservoirs also transports fluid pressure to the pressure transfer element for conveyance to the diaphragm.

User interface and monitoring functions for automated peritoneal dialysis systems

Abstract: Systems for performing peritoneal dialysis having an improved user interface functions and monitoring capabilities. In one respect, the systems discriminate between alarm conditions that require user intervention to correct and alarm conditions that reflect conditions that are anomalies but typically correct themselves with minimum or no user intervention. In another respect, the systems identify occluded liquid flow paths and discriminate whether the flow path is associated with a liquid source or a liquid destination.