Papers by Rosa Marat-Mendes
An angular acceleration measurement system using a piezoelectric material is described. The piezo... more An angular acceleration measurement system using a piezoelectric material is described. The piezoelectric material used in the sensor was either a pre-polarised PVDF film or a polymer/ceramic piezoelectric composite of (PTCa:P(VDF/TrFE) 50:50 vol %)
Bookmarks Related papers MentionsView impact
Sensors and Actuators A-physical, 1999
Bookmarks Related papers MentionsView impact
Ferroelectrics, 1999
ABSTRACT An acceleration measurement system using a piezoelectric material is described. The main... more ABSTRACT An acceleration measurement system using a piezoelectric material is described. The main advantages of this sensor are that it has a very low cost compared with other sensors and that there are no moving parts. The piezoelectric material used in this sensor was a pre-polarized PVDF film.
Bookmarks Related papers MentionsView impact
IEEE Transactions on Dielectrics and Electrical Insulation, 2004
... ceramic grains in the sub-micron range enabling the production of nanocomposites with electro... more ... ceramic grains in the sub-micron range enabling the production of nanocomposites with electro ... gels have been described in a previous wx publication 5 . These ferroelectric ceramic powders ... critical stage of the sol-gel method in the preparation of ferro-electric ceramic powders ...
Bookmarks Related papers MentionsView impact
Key Engineering Materials, 2002
ABSTRACT In this work we present a comparative study of piezoelectric materials using an angular ... more ABSTRACT In this work we present a comparative study of piezoelectric materials using an angular accelerometer to test them. The piezoelectric materials used in this work were either a pre-polarised PVDF film, a pre-polarised PTCa plate, a pre-polarised PZT plate or a polymer/ceramic piezoelectric composite of (PTCa:P(VDF/TrFE) 50:50vol%). The PVDF used in this work is from SOLEF, piezo film with a value of 25 ± 5 pC/N for the piezoelectric coefficient, d33. The PTCa (Calcium modified lead titanate) material comes from Morgan Matroc, with the reference, PC6. Its value for the piezoelectric coefficient is 65 pC/N. PZT, i.e. the Lead Zirconate Titanate is another of the piezoelectric materials used in this work, which is also from Morgan Matroc, with the reference, PC5H and has a high piezoelectric constant, of about 520 pC/N The composite material is a polymer/ceramic mixture of [(PTCa:P(VDF:TrFE))(50:50vol%)] with 50% of lead titanate modified with calcium and 50% of polyvinylidene difluoride with trifluorethylene. It is therefore flexible and has a reasonable piezoelectric activity. This composite was made in the School of Electronic Engineering and Computer Systems, University of Wales, Bangor, UK, with a value for piezoelectric coefficient of 25 ± 8 pC/N. The angular accelerometer used to study the several materials consists of a circular plate with two masses connected mechanically and electrically between them. Between the masses and the plate (on each side of it) is glued a piece of piezoelectric material metalized and polarized. The experimental results are in good agreement with the theoretical ones, however the best results are obtained when the piezoelectric ceramic PZT was used. This is due to the higher piezoelectric activity of this material.
Bookmarks Related papers MentionsView impact
Engineering Fracture Mechanics, 2009
ABSTRACT An experimental and numerical investigation were carried out on a glass/epoxy laminate t... more ABSTRACT An experimental and numerical investigation were carried out on a glass/epoxy laminate to evaluate the edge crack torsion (ECT) test to determine its suitability for inducing mode III delamination growth. Two fixtures were used: an original and a modified ECT test which differ from each other in the constraints. The finite element analysis of the original ECT specimens without constraints in the guide pins showed that the propagation of mode III appears in the middle of the sample away from both ends, while with constraints, the propagation in mode III appears in the side of the loading point. For the modified ECT specimens with constraints the mode III dis- tribution is similar to that occurring in the original ECT specimens without constrains. A C’scan analysis of the original and modified ECT specimens showed that delamination grows near the loading point for a load just after initial delamination.
Bookmarks Related papers MentionsView impact
Bookmarks Related papers MentionsView impact
Composite Structures, 2010
Bookmarks Related papers MentionsView impact
Bookmarks Related papers MentionsView impact
Uploads
Papers by Rosa Marat-Mendes