Application of bone growth factors—the potential of different carrier systems

Aim The aim of the present review was to characterize the potential of different biomaterials as carriers for bone growth factors. Introduction Beyond mechanical and structural characteristics, one of the features that account for a potential carrier is the possibility to couple growth factor molecules to it. As simple adsorption of the growth factor to the carrier surface by soak loading produces a burst release of growth factors with rapid decrease of biological activity, the ability to accomplish controlled release of functional growth factor molecules is one of the crucial characteristics for an appropriate carrier material. Conclusion The variety of carrier materials requires different strategies to either couple growth factors to the material surface or to incorporate them into the carrier matrix. The present review outlines current technical approaches and discusses future trends in the use of carrier materials for bone growth factors

A CFD study on the strut interference on a regional aircraft wind-tunnel model

Abstract The aim of this paper is to investigate the aerodynamic interference effects of typical devices supporting aircraft models during wind tunnel tests by means of CFD tools. This work proposes the use of steady RANS simulations of the flow field in order to predict the interference produced by two different models of struts: (1) one that is made up of two parts and is solidal with the wind-tunnel model for variation of the angles of incidence (α) and of the angles of sideslip (β) and (b) the second that is made up of one part and is fixed for α variations and is solidal with the model for β variations. Low and high Reynolds flow conditions are considered and a typical cruise configuration of a scaled model of regional aircraft is addressed in both power-off and power-on conditions. The strut effect is investigated for several angles of incidence and sideslip. From the numerical point of view, the flow field and forces disturbance caused by the struts are derived by comparing simulations with and without the support. The interference is analysed in terms of global forces and moments coefficients and local quantities, such as pressure coefficients distributions. The main result regarding the comparison between the two models of strut is that the corrections to be applied to experimental data and the effect of both ventral struts on the global aerodynamic forces and moments are small.</jats:p

A CSM-CFD methodology applied to the design of a cryogenic WT model

Abstract The Aero-structural coupled analysis presented in this work represents an important part of the PRODIGE project, whose main purpose is the prediction of aerodynamics and hinge moment loads of the aileron of a scale model of business jet at transonic Mach numbers and flight Reynolds number. More in details, this methodology supports the design activities of the cryogenic wind-tunnel (WT) model to be tested in the European Transonic Wind tunnel (ETW). The need to implement such a kind of analysis comes from the requirement to take into account the “pure aeroelastic effect” during experimental tests and need to understand the effect of the WT model flexibility on the control surface load prediction, prior to and in parallel with the balance design. CFD evaluations are performed on the whole model, while a static Fluid-Structure-Interface (FSI) procedure is set up and, only, applied to the wing and aileron of the model. The FSI cycle is made of two blocks: a CFD evaluation part and a CSM evaluation part. Both modules are coupled within an iterative loop, where information are exchanged between them. Two angles of incidence are taken into account, i.e. the lowest value (α=-3°) and the highest one (α=6°). Results will be compared in terms of global aerodynamic forces and pressure coefficient distributions. Moreover the new deformed shapes derived from the application of both approaches will be compared with the original one.</jats:p

Preliminary studies of flight sensoring for loads and aeroelastic parameters estimation of the NGCTR-TD wing

Abstract The paper presents the preliminary analyses carried out to estimate the accelerom-eters and strain gauges optimal configuration for the in-flight natural modes and internal loads identification of the Next Generation Civil Tilt Rotor Technology Demonstrator (NGTCTR-TD) wing. The optimal accelerometers’ configuration has been achieved with the aeroelastic model by taking into account the modal displacements of the targeted natural modes, requirements of space availability and accessibility. A further analysis has been set up to estimate the accel-eration peak on the wing by using a continuous turbulence model with a von Karman power spectral density. The optimal strain gauges’ configuration has been achieved as a subset of an initial layout by using the Skopinski methodology, where quality ratios and percentual errors lead to the identification of redundant and irrelevant measurements. This approach aims to recover the flight loads on the wing from an optimal set of strain measurements during flight. The present work has been a numerical study. A verification of the final Load Evaluation Matrix (LEM) has been performed using a set of validation load cases.</jats:p

Damage evolution under cyclic multiaxial stress state: A comparative analysis between glass/epoxy laminates and tubes

In this work an experimental investigation on damage initiation and evolution in laminates under cyclic loading is presented. The stacking sequence [0/\u3b82/0/ 12\u3b82]s has been adopted in order to investigate the influence of the local multiaxial stress state in the off-axis plies and the possible effect of different thickness between the thin (2-plies) and the thick (4-plies) layers. Results are presented in terms of S\u2013N curves for the initiation of the first cracks, crack density evolution, stiffness degradation and Paris-like curves for the crack propagation phase. The values of the off-axis angle \u3b8 has been chosen in order to obtain local multiaxial stress states in the off-axis plies similar to those in previous studies for biaxially loaded tubes. Results concerning damage initiation and growth for these two specimen configurations are shown to be consistent for similar local multiaxial stress states