No abstract

No abstract

Obesity constitutes a serious health problem. Inflammation, which has recently been shown to follow adipocyte death, is at the basis of a series of pathogenic complications of obesity. Here we demonstrate, through modelling using the finite element method, that the bigger the adipocyte, the more fragile it becomes to rupture when submitted to common physical forces. This indicates that adipocyte size is an important determinant of cell death. Interventions to prevent adipocyte hypertrophy may, therefore, help to reduce the risk associated with obesity.

No abstract

No abstract

Low velocity impact damage can significantly reduce the residual strength of laminated composites. This kind of damage (mostly delaminations) is very dangerous for the structures because it is not apparent to the naked eye and, in some cases, it can reduce the compressive residual strength up to 60%. In this work, a numerical model for predicting the compression failure of laminated composites containing delamination caused by low velocity impact was developed. An interface finite element, previously developed by the authors, was used. This element is compatible with twenty-seven node isoparametric hexahedral elements and enables modeling the behavior of the damaged interface, taking into account a three-dimensional stress state, the interpenetration constraint and the propagation of delamination. In order to verify the numerical model, some experimental work was done. The experimental work, performed on carbon-epoxy (04, 904)5 and (904, 04), laminates, included low velocity impact tests using a drop weight testing machine, followed by X-Ray damage characterization and compression tests using a fixture system similar to IITRI system. The numerical and experimental results were compared and good agreement was obtained.

No abstract

An interface finite element for three-dimensional problems based on the penalty method is presented. The proposed element can model joints/interfaces between solid finite elements and also includes the propagation of damage in pure mode I, pure mode II and mixed mode considering a softening relationship between the stresses and relative displacements. Two different contact conditions are considered: point-to-point constraint for closed points (not satisfying the failure criterion) and point-to-surface constraint for opened points. The performance of the element is tested under mode I, mode II and mixed mode loading conditions.