Using variational mechanics we present mathematical bounds on the effective modulus of a crossply laminate containing microcracks in the 90◦ plies. An average of the two bounds provides an effectively exact solution to the modulus reduction problem. The problem of predicting microcracking is reduced to finding the energy release rate for formation of a complete microcrack. From the bounds on ef...

Passive solar systems such as solar chimneys need solar radiation in order to work. Therefore, they cannot present stable natural ventilation when solar energy vanishes: to have a more robust and stable condition, solar energy should be stored during the day and released back during the night. Phase change materials can save additional thermal energy during the day and release it during the...

The plane strain problem of determining strain energy release rate, crack energy, and crack-opening displacement (COD) for a moving Griffith crack at the interface of two dissimilar orthotropic half-planes is considered. The problem is reduced to a pair of singular integral equations of second kind which have finally been solved by using Jacobi polynomials. Graphical plots of the strain energy ...

Results are presented from a numerical investigation of the effect of the shape of the delamination front on energy release rate distribution in a laminated carbon fibre reinforced epoxy end-notched flexure test specimen. The deformation behaviour of the specimen has been computed by threedimensional nonlinear finite element analyses using a recently developed layered 3D-shell element. The dist...

In this study, the energy release rates in a centrally perforated star-shaped disk, which was made of a polymeric material, under internal pressure and thermal loads, were determined. The deformations of the disk were constrained by a circular steel ring enclosing the disk. Two constitutive models, namely, Hookean model and Ogden model, were used to model the constitutive behavior of the materi...

Passive solar systems such as solar chimneys need solar radiation in order to work. Therefore, they cannot present stable natural ventilation when solar energy vanishes: to have a more robust and stable condition, solar energy should be stored during the day and released back during the night. Phase change materials can save additional thermal energy during the day and release it during the nig...

By using the method presented by Isobe et al. (2002), the non-dimensional reconnection rate vin/vA has been determined for the impulsive phase of three two-ribbon flares, where vin is the velocity of the reconnection inflow and vA is the Alfvén velocity. The non-dimensional reconnection rate is important to make a constraint on the theoretical models of magnetic reconnection. In order to reduce...

The fracture mechanics of electromechanical materials has been investigated for well over a decade, yet there still exists controversy over the appropriate crack face boundary conditions for non-conducting cracks. In this paper an experimental protocol for measuring the energy release rate in a non-linear reversible electromechanical body is proposed and summarized. The potential results from t...

We consider the quasi-static evolution of a straight crack within the recent phase field approach and the classical sharp crack approach. We show a strong correlation between the two approaches: energy, minimizers, energy release rate and quasi-static evolutions converge as the internal length parameter of the phase-field approach tends to zero. A crucial point in the proof is a novel represent...