Computational Model for Delamination Growth at SMA-GFRP Interface of Hybrid Composite

AbstractA cohesive model of the new interface of the CuZnAl SMA/GFRP hybrid composite is proposed and the interfacial delamination under Mode II loading conditions, between plain CuZnAl SMA sheet insert and GFRP matrix, as well as between CuZnAl SMA sheet insert having elliptical hole pattern and GFRP matrix, are studied in detail.The results of the pull-out tests with plain sheet insert are used to calculate the interfacial parameters of the hybrid composite. With these parameters, the cohesive interaction and failure mechanism for hybrid composite with plain sheet, as well as with patterned sheet insert, is modelled. The efficacy of the laser patterned SMA sheet inserts to improve the overall interfacial strength in the new laminated SMA/GFRP hybrid composite for applications, such as light weight and high damping material under dynamic loads, is validated

Cohesive surface model for delamination and dynamic behavior of hybrid composite with SMA-GFRP interface

The interface model between CuZnAl SMA and GFRP, used in a hybrid composite, is proposed using cohesive surfaces. Using this model and derived parameters, mode-II delamination is studied between CuZnAl SMA insert and GFRP and also between laser patterned CuZnAl SMA insert and GFRP. Natural frequency and damping ratio of the hybrid composite specimen, in the shape of slender beam in a cantilever configuration, are evaluated in impulse tests. A numerical model is also presented, to calculate the aforementioned dynamic properties numerically, using Modal Strain Energy (MSE) and Modal Dynamics procedures by considering the derived interfacial parameters. Keywords: Hybrid composite, Delamination, FE analysis, Cohesive interface, Damage initiation, Modal dynamic

Adherence issues related to sublingual immunotherapy as perceived by allergists

Objectives: Sublingual immunotherapy (SLIT) is a viable alternative to subcutaneous immunotherapy to treat allergic rhinitis and asthma, and is widely used in clinical practice in many European countries. The clinical efficacy of SLIT has been established in a number of clinical trials and meta-analyses. However, because SLIT is self-administered by patients without medical supervision, the degree of patient adherence with treatment is still a concern. The objective of this study was to evaluate the perception by allergists of issues related to SLIT adherence. Methods: We performed a questionnaire-based survey of 296 Italian allergists, based on the adherence issues known from previous studies. The perception of importance of each item was assessed by a VAS scale ranging from 0 to 10. Results: Patient perception of clinical efficacy was considered the most important factor (ranked 1 by 54% of allergists), followed by the possibility of reimbursement (ranked 1 by 34%), and by the absence of side effects (ranked 1 by 21%). Patient education, regular follow-up, and ease of use of SLIT were ranked first by less than 20% of allergists. Conclusion: These findings indicate that clinical efficacy, cost, and side effects are perceived as the major issues influencing patient adherence to SLIT, and that further improvement of adherence is likely to be achieved by improving the patient information provided by prescribers. © 2010 Scurati et al, publisher and licensee Dove Medical Press Ltd

The Magnetoelastic Contribution to the Steel Internal Damping

In this paper, the steel internal damping due to both the thermoelastic and the magnetoelastic phenomena has been investigated through a formulation based on thermodynamical potential joints with a hysteretic damping model. With the aim of focusing on the temperature transient in the solid, a first configuration has been considered, which is characterized by a steel rod with an imposed alternating pure shear strain in which only the thermoelastic contribution was studied. The magnetoelastic contribution was then introduced in a further configuration, in which a steel rod in free motion was subjected to torsion on its ends in the presence of a constant magnetic field. A quantitative assessment of the influence of the magnetoelastic dissipation in steel has been computed according to the Sablik-Jiles model by giving a comparison between the thermoelastic and the prevailing magnetoelastic damping coefficients

Metal Matrix Composites: Design and Methodology

Metal matrix composites (MMCs) are materials that exhibit unusual property combinations and unique design possibilities. This article provides an overview of techniques for analysis in the design of MMC materials. Starting with the micromechanics of the reinforcement and matrix, methods that account for damage initiation and evolution are considered. The inhomogeneous composite is represented by a homogeneous material, which is often anisotropic, with the effective properties of the composite. Properties of interest for evaluating stress and strain are as follows: elastic engineering properties, coefficient of thermal expansion and thermal conductivity, yield strength, and hardening parameters. Thermomechanical loading is considered to be an integral aspect of stress analysis with MMCs. Approach to achieve higher levels of performance in critical industrial applications with copper matrix composites, high conductivity composites, nanoscale composites, are also discussed