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Resumen del póster presentado a la 3rd International Conference on Polymer Replication on Nanoscale, celebrada en Switzerland del 19 al 20 de mayo de 2016., Within the www.aim4np.eu project, a metrology platform hosting an Atomic Force Microscope [AFM] will be used for the determination of the nanomechanical objects’ surfaces at production sites enabling inline process control. Plastic injection was chosen as a case system for the validation-study. The goal is to determine the influence of the micro/nano roughness of a mould and the roughness of the resulting part. The determination of the link between the nanomechanical properties mould’s surface and the functionality of the mould is addressed both by means of experimental and simulation techniques. Moulds and moulded plastic parts have been characterized by AFM and other techniques, and computer models have been developed to simulate the effect of mould surface roughness on the appearance of the final plastic piece. All available simulation codes devoted to plastic injection have so far been conceived for large pieces in industrial applications (e.g. automotive) with dimensions well above the millimetre range. Thus, it was foreseeable that the extension of such codes down to the nanometre range would be challenging. Therefore, we were driven to develop the necessary code to carry out nano-simulations: ANSYS Fluent capabilities are expanded with own-developed User Defined Functions. The aim is to obtain a model able to forecast the relationship between the depth of the mould’s marks (blue line) and how much they are replicated by the polymer (red line).

Póster presentado a la Conferencia Industrial Technologies: "Creating a Smart Europe", celebrada en Amsterdam del 22 al 24 de junio de 2016., Within the www.aim4np.eu project, a metrology platform hosting an Atomic Force Microscope [AFM] will be used for the determination of the nanomechanical properties of surfaces of objects at a production site enabling inline process control., This project has received funding from the European Union’s Seventh Framework Programme for research, technological development and demonstration under Grant agreement No. 309558.

Trabajo presentado al Second International Workshop on Software Solutions for Integrated Computational Materials Engineering, celebrado en Barcelona (España) del 12 al 15 de abril de 2016., Within the www.aim4np.eu project, a metrology platform hosting an Atomic Force Microscope [AFM] will be used for the determination of the nanomechanical properties of surfaces of objects at a production site enabling inline process control. Under the nanomechanical properties term we include roughness, adhesion and elasticity. The underlying concept is based on the artificially generated stiffness between the surface to be characterized and the metrology platform using a feedback sensor-actuator system. Plastic injection was chosen as a case system for the validation-study. The goal is to determine the influence of the surface micro/nano roughness of a mould and the performance of the injection moulding process. The determination of the link between the nanomechanical properties of the surface of the mould and the functionality of the mould (that is the surface roughness and defect density of the moulded plastic part) is addressed both by means of experimental and simulation techniques. Moulds and moulded plastic parts have been characterized by AFM and other techniques, and computer models have been developed to simulate the effect of mould surface roughness on the appearance of the final plastic piece. All available simulation codes devoted to plastic injection have so far been conceived for large pieces in industrial applications (e.g. automotive) with critical dimensions well above the millimetre range. Thus, it was foreseeable that the extension of such codes down to the micro- and nanometre range would be challenging, given the used approximations and boundary conditions in the codes. For this reason, the emphasis was initially laid on the experimental part to address the relevant magnitudes of parameters of technical surfaces, such as roughness and morphology. Trying to directly replicate the roughness of the mould surface was a too demanding objective. It was therefore decided to start with the study of well-defined simple patterns in the micrometre-range. Different strategies have been pursued in order to implement available codes to the micro/nanometre range. A first innovative approximation consists in simulating a rough surface by a regular array of semicircles using submodeling. Such an approximation has revealed to be successful and fairly describes the actual morphology of the coated diamond-like carbon films used as protection of the stainless steel surfaces of the moulds. Comparison of Sq roughness values of mould and plastic parts in range 5 to 40 nm are shown in simulation and compared to experiments to conclude that roughness of plastic part is lower than mould part as predicted by simulation., aim4np: Seventh Framework Programme.

This paper reviews how biomedical engineers, in collaboration with physicians, biologists, chemists, physicists, and mathematicians, have developed models to explain how the impact of vascular interventions on blood flow predicts subsequent vascular repair. These models have become increasingly sophisticated and precise, propelling us toward optimization of cardiovascular therapeutics in general and personalizing treatments for patients with cardiovascular disease., Spain. Ministerio de Ciencia e Innovacion (Plan Nacional BFU2009-09804), National Institutes of Health (U.S.) (Grant NIH/NIGMS RO1/GM049039), Spain. Generalitat de Catalunya (FI-DGR 2011), Barcelona Chamber of Commerce, Fundacao Empreses IQS, POSIMAT

Trabajo presentado a la International MicroNano Conference, celebrada en Amsterdam (Netherlands) del 8 al 9 de diciembre de 2015, Introduction to aim4np project Plastic injection application of aim4np Plastic injection is selected as a possible application for aim4np to control moulds and plastic parts in-line to assure surface quality. [Aim]: Expand the Fluent solver capacity to the nanoscale and obtain a model correlating mould roughness with part roughness using simulation and experimental results., Aim4np is a FP7 funded project to build an Automated In-line Metrology for (4) Nanoscale Production.

Fastener holes in aircraft components are routinely cold expanded to improve fatigue life, although the precise level of improvement is difficult to quantify. This paper describes an attempt to predict the growth rate of a fatigue corner crack emanating from the bore of a cold expanded hole. The prediction is made using a three-dimensional finite element model of a cold expanded hole combined with a Paris law fit to fatigue data derived from tests for corner cracks emanating from a plain hole. Residual stresses in the finite element model are calculated from a simulation of the cold expansion process. Finite element predictions of fatigue crack growth rate are compared with experimental measurements giving adequate agreement.

The cold expansion of fastener holes in aircraft components is a standard technique to improve fatigue life. There is concern that the beneficial residual stresses arising from cold expansion may relax due to creep. This paper describes experimental measurement and finite element prediction of cold expansion residual stresses and their redistribution after creep, with and without additional mechanical load. Experimental measurements of near-surface stresses used an X-ray diffraction technique while average through-the-thickness stresses were measured using a new method based on Sachs’ boring. This new method allowed non-axisymmetric residual stresses to be measured, as was the case when creep relaxation occurred with mechanical load. Axisymmetric and three dimensional finite element analyses were used to predict the stress distribution through the thickness of the component showing good agreement with measurement. Creep relaxation of residual stress does indeed occur, but some benefit of the cold expansion remains, particularly when creep relaxation is combined with the application of mechanical load.

Sachs’ boring is an established technique for the measurement of axisymmetric residual stresses in cylindrical components. There are however important cases where non-axisymmetric residual stresses need to be found. In this paper a new procedure is developed to measure non-axisymmetric residual stresses. The essential feature of the new procedure is the use of a Fourier series to represent the residual stresses. The correctness of the new procedure is demonstrated using a finite element simulation where a set of non-axisymmetric residual stresses are determined. Excellent agreement is found between the predicted residual stresses and those derived using a finite element simulation of the new procedure.

The Sachs boring technique is used widely to determine residual stresses in axisymmetric components. Several studies have attempted to use this standard method to determine residual stresses where the measured strains are non-axisymmetric. In this paper a new procedure to measure non-axisymmetric residual stresses is presented. The new method is based on a Fourier analyses of the measured strains. The analysis determines radial, tangential and shear tangential stresses as a function of angle and radial distance. The solutions provided can be applied to plane stress and plane strain conditions. The accuracy of the new method is validated using a FE simulation to generate a non-axisymmetric residual stress distribution. FE simulation of material removal and strain readings is also conducted. Finally the residual stresses are calculated using both Sachs conventional axisymmetric analysis and the new Fourier analysis. The new method determines accurately the non-axisymmetric residual stress distributions, while the conventional method provides only an average distribution.

The synthesis of mono- and trihalogenated derivatives of 2-aza 1,3-dienes 2 and 3 is described. The first example of diastereofacial selectivity in Diels-Alder reactions of heterodienes of type 2 with electron-poor dienophiles is reported, and a model for the explanation of the observed epimeric ratios, based on the interactions between diene and dienophile, is proposed

Ball-burnishing induces compressive residual stresses on treated materials by the effect of plastic deformation. The result is an increase in the fatigue life of the treated part, retarding the initiation of cracks on the surface. Compressive residual stresses have been previously measured by X-ray diffraction near the surface, revealing considerably high values at the maximum analyzed depth, in relation to other finishing processes such as shot peening. However, the maximum analyzed depth is very limited by using this technique. In this paper, the incremental hole drilling (IHD) technique is tested to measure residual stresses, being able to reach a 2-mm measuring depth. To that objective, a commercial strain gage is used and calibrated using finite element model simulations. A second Finite Element Model based on material removal rate is developed to obtain the equations to calculate the strain release through IHD. Finally, residual stresses are measured experimentally with that technique on two different materials, confirming that ball-burnishing increases the compressive residual stresses in layers up to 0.5¿mm deep for the testing conditions, which is a good response to industrial needs. The method proves to be suitable, simple and inexpensive way to measure the value of these tensions.