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Predictive models play an important role for increasing the reliability of composite structures over time, but a great deal of experimental data is requested. In this paper, results from creep experiments on uniaxial E‐glass fiber reinforced polymer (FRP) single ply laminates, performed at different stress levels, are presented. The tests duration was of 42 months. Analytical modeling of the viscous behavior of the tested GFRP composite, under linear and nonlinear viscoelastic hypotheses, is reported. A discussion on the comparison of creep strain response by Burgers model, with parameters obtained from fitting of data for different test duration, is also proposed. Finally, predictive finite element method (FEM) simulations were carried out for discussing the deferred behavior induced by creep, for composite layers used for repair purposes in hydrogen transportation pipes. Numerical results highlighted a non‐negligible difference in creep strain values, pointing out that a model based on experimental tests with shorter duration leads to a conservative composite design. [ABSTRACT FROM AUTHOR]

A fatigue test on a full scale panel with complex loading condition and geometry configuration has been carried out using a triaxial test machine. The demonstrator is made up of two skins which are linked by a transversal butt-joint, parallel to the stringer direction. A fatigue load was applied in the direction normal to the longitudinal joint, while a constant load was applied in the longitudinal joint direction. The test panel was instrumented with strain gages and previously quasi-static tests were conducted to ensure a proper load transferring to the panel. In order to support the tests, geometric nonlinear shell finite element analyses were conducted to predict strain and stress distributions. The demonstrator broke up after about 177000 cycles. Subsequently, a finite element analysis (FEA) was carried out in order to correlate failure events; due to the biaxial nature of the fatigue loads, Sines criterion was used. The analysis was performed taking into account the different materials by which the panel is composed. The numerical results show a good correlation with experimental data, successfully predicting failure locations on the panel. [ABSTRACT FROM AUTHOR]

This paper concerns the numerical simulations, by a commercial FEM code, related to notched specimens experimentally tested by neutron diffraction and synchrotron radiation diffraction, in order to correlate the deformation states around the crack tip. Two cracked specimens were analyzed. In one case a long crack has been induced into the specimen, which has been investigated subsequently by neutron diffraction technique. In the other case a smaller crack was induced, which has been investigated by synchrotron radiation diffraction technique. The numerical and experimental results are substantially in good agreement. However some differences can be observed; the reason can be found in the microscopic structure and particular history of the material under load. [ABSTRACT FROM AUTHOR]

Purpose – The major objectives of this study are the engineering development and the structural analysis with finite element method (FEM) of a refrigerated container having a passive equipment and a remote control system to carry both fresh (+4°C÷±1°C) and frozen (−18°C÷−20°C) goods. The purpose of this paper is to offer some solutions to the many disadvantages of using phase change material (PCM) to refrigerate the insulated container for transporting both fresh and frozen goods. Design/methodology/approach – In order to transport both fresh products (+4°C÷±1°C) and frozen products (−18°C÷−20°C), the PCM elements are filled with one eutectic liquid only, so as to avoid problems related to filling and emptying the eutectic plates, and to plate corrosion. Moreover, specially shaped air ducts and a cool flow control system are designed to maintain a uniform circulation of cool air and constant humidity values. All the structures of the container are correctly designed by means of FEM calculations to assure that all the structural, safety standards parameters are satisfied. Findings – An innovative refrigerated container with PCM and a remote control system used to transport both fresh (+4°C÷±1°C) and frozen (−18°C÷−20°C) products, in which it is possible to maintain the temperature values for almost seven days, has been considered here. Many disadvantages due to the use of PCM have been eliminated. It is possible to maintain a uniform circulation cool air and humidity values within the design parameters by means of fans; moreover, this container is light and environmentally friendly. All structures of the container are designed using FEM. Originality/value – This paper presents a refrigerated container with passive equipment and a remote control system to carry both fresh (+4°C÷±1°C) and frozen (−18°C÷−20°C) goods in which it is possible to maintain the temperature values necessary for almost seven days. The container is equipped with a remote control system powered by photovoltaic panels which works in real time, is capable of giving information about the environmental parameters set in it and monitors the state of products by means of a network of sensors. Furthermore, the remote control system can send information about the position of the container to a remote control centre. The relevant structural conditions are numerically (FEM) evaluated and reported. [ABSTRACT FROM AUTHOR]