Paulo Reis - Academia.edu (original) (raw)

Papers by Paulo Reis

Applied Mechanics and Materials, 2007

The aim of present work is to study the influence of the impactor diameter and boundary condition... more The aim of present work is to study the influence of the impactor diameter and boundary conditions on low velocity impact on carbon-fibre-reinforced epoxy laminates. Experimental tests were performed on [04,904]s laminates, using a drop weight-testing machine. Circular plates were tested under low velocity impacts for two diameters of the hemispherical impactor, 12.7 mm and 20 mm, and considering similar impact energies, 2.6 J for the first impactor and 3 J for the second one. Rectangular and square plates were analysed under low velocity impacts with different boundary conditions. The impacted plates were inspected by X-radiography. Numerical simulations were also performed considering interface finite elements compatible with three-dimensional solid elements including a cohesive mixed-mode damage model, which allows to model delamination between layers. The impact tests showed that both the impactor’s diameter and boundary conditions have influence on the delaminated area. Good ag...

The 1st International Online Conference on Buildings

This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY

Processes

It is very important to understand the damage mechanisms as well as the mechanical response of T-... more It is very important to understand the damage mechanisms as well as the mechanical response of T-joints involving different materials on the base plate. For this purpose, two configurations were studied. In one, the joint is composed of a base plate and a T-element, both in Al 6063-T5, while in the other one, the aluminum base plate was replaced by a glass fiber composite. Finally, each configuration was divided into two batches, where in one, the elements were bonded with a stiff adhesive (Araldite® AV 4076-1/HY 4076) while in the other, a more ductile adhesive (Araldite® AW 106/HV 953 U) was used. The static and fatigue strength of all configurations was evaluated in bending. In all cases, the damage occurred at the end of the T-element, where a crack appeared and propagated toward the interior of the T-joint. The bending strength is highest for joints involving aluminum and the ductile adhesive, which is 2.8 times higher than the same configuration involving composite base plates...

Theoretical and Applied Fracture Mechanics, 1999

This paper is concerned with fatigue of polypropylene/glass-®bre thermoplastic composites produce... more This paper is concerned with fatigue of polypropylene/glass-®bre thermoplastic composites produced from a bidirectional woven cloth mixture of E glass ®bres and polypropylene ®bres. The latter becomes the matrix after the application of heat and pressure. This composite was manufactured with a ®bre volume fraction V f of 0.338. The eect of layer design on the static and fatigue performance was investigated. The S±N curves, the rise in the temperature of the specimens during the tests and the loss of stiness, were obtained and discussed. The loss of stiness was related to the rise of temperature and stress release observed in the material. The eect of load rate on the static properties was also studied and discussed accordingly.

International Journal of Fatigue, 1996

The titanium grade 2 is currently used in high-pressure heat exchanges, piping systems in sea wat... more The titanium grade 2 is currently used in high-pressure heat exchanges, piping systems in sea water desalination plants, offshore technology and chemical plants. In many of the applications fatigue and/or creep loading conditions occur. In this paper are presented the results of the mechanical behaviour, low cycle fatigue parameters and fatigue crack propagation at room temperature and at 400°C. The influence of temperature, frequency and the shape of wave loading was studied. The creep behaviour was also studied. Curves of the strain and the stress against the time were obtained to 400°C and 500°C. Also the Larson-Miller parameter was determined. Tests to the creep crack propagation study were carried out. Crack propagation in the creep tests conditions used was not verified.

Fibers and Polymers, 2011

Composites Science and Technology, 2009

This paper presents the results of current research on the fatigue life prediction of carbon/epox... more This paper presents the results of current research on the fatigue life prediction of carbon/epoxy laminate composites involving twelve balanced woven bidirectional layers of carbon fibres and epoxy resin manufactured by a vacuum moulding method. The plates were produced with 3 mm thickness and 0.66 fibre weight fraction. The dog bone shape specimens were cut from these plates with the load line aligned with one of the fibre directions. The fatigue tests were performed using load control with a frequency of 10 Hz and at room temperature. The fatigue behaviour was studied for different stress ratios and for variable amplitude block loadings. The damage process was monitored in terms of the stiffness loss. The fatigue life of specimens submitted to block loading tests was modelled using Palmgren-Miner's law and taking in to account the stress ratio effect. The estimated and experimental fatigue lives were compared and good agreement was observed.

Applied Composite Materials, 2010

Page 1. Fatigue Damage Characterization by NDT in Polypropylene/Glass Fibre Composites Paulo NB R... more Page 1. Fatigue Damage Characterization by NDT in Polypropylene/Glass Fibre Composites Paulo NB Reis & José AM Ferreira & Mel OW Richardson © Springer Science+Business Media BV 2010 Abstract This paper presents ...

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