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Shape memory alloys (SMAs) are gaining popularity in the fields of automotive and aerospace engineering due to their unique thermomechanical properties. This paper proposes a numerical implementation of a comprehensive constitutive model for simulating the thermomechanical behavior of shape memory alloys, with temperature and strain as control variables to adjust the shape memory effect and super elasticity effect of the material. By implementing this model as a user subroutine in the FE code Abaqus/Standard, it becomes possible to account for variations in material properties in complex components made of shape memory alloys. To demonstrate the potential of the proposed model, a skid plate system design is presented. The system uses bistable actuators with shape memory alloy springs to trigger plate movement. The kinematics and dynamics of the system are simulated, and effective loads are generated by the shape memory alloy state change due to the real temperature distribution in the material, which depends on the springs’ geometrical parameters. Finally, the performance of the actuator in switching between different configurations and maintaining stability in a specific configuration is assessed. The study highlights the promising potential of shape memory alloys in engineering applications and demonstrates the ability to use them in complex systems with accurate simulations.

In the last decades, the interest in Shape Memory Alloys (SMA) materials has been considerably increased due to their peculiar morphing capabilities, which can be relevant for many different engineering fields such as automotive and aerospace. Among the characteristics of shape memory alloys, their super-elastic behavior and their capability to recover an initial state, once a deformation has occurred, when subjected to a temperature above a predefined threshold, can be considered the most attractive ones. Possible applications of SMA includes, but are not limited to, switch actuators and morphing structures. In this work, the SMA materials super-elasticity effect and their capability to recover an initial state, due to the heating, are described and numerically reproduced by means of a user material routine implemented in the ABAQUS Standard FEM environment. A test-case representative of a mechanical actuator operated by SMA springs is introduced to assess the robustness of the developed numerical procedure for the simulation of Shape Memory Alloys material behavior.

The occurrence of several geriatric conditions may influence the efficacy and limit the use of drugs prescribed to treat chronic conditions. Functional and cognitive impairment, geriatric syndromes (i.e. falls or malnutrition) and limited life expectancy are common features of old age, which may limit the efficacy of pharmacological treatments and question the appropriateness of treatment. However, the assessment of these geriatric conditions is rarely incorporated into clinical trials and treatment guidelines. The CRIME (CRIteria to assess appropriate Medication use among Elderly complex patients) project is aimed at producing recommendations to guide pharmacologic prescription in older complex patients with a limited life expectancy, functional and cognitive impairment, and geriatric syndromes, and providing physicians with a tool to improve the quality of prescribing, independent of setting and nationality. To achieve these aims, we performed the following: (i) Existing disease-specific guidelines on pharmacological prescription for the treatment of diabetes, hypertension, congestive heart failure, atrial fibrillation and coronary heart disease were reviewed to assess whether they include specific indications for complex patients; (ii) a literature search was performed to identify relevant articles assessing the pharmacological treatment of complex patients; (iii) A total of 19 new recommendations were developed based on the results of the literature search and expert consensus. In conclusion, the new recommendations evaluate the appropriateness of pharmacological prescription in older complex patients, translating the recommendations of clinical guidelines to patients with a limited life expectancy, functional and cognitive impairment, and geriatric syndromes. These recommendations cannot represent substitutes for careful clinical consideration and deliberation by physicians; the recommendations are not meant to replace existing clinical guidelines, but they may be used to help physicians in the prescribing process.

Changes in pharmacokinetics and pharmacodynamics, associated with increasing age, are often considered the only culprits of increasing Adverse Drug Reactions (ADR) rate observed in older adults, but other factors may be responsible for a reduction in drug efficacy and increase the risk of iatrogenic illness in this population. The aging process is characterized by a high level of complexity, which makes the care of older adults and the use of medications a challenging task. In particular, comorbidity, geriatric syndromes, cognitive and functional deficits, limited life expectancy are typical conditions observed in older adults which may reduce the efficacy of prescribed drugs and increase the risk of iatrogenic illness. As a consequence, a comprehensive assessment and management of the health care problems, with the goal of recognizing and preventing potential drug-related problems and improve quality of prescribing is necessary to reduce the risk of ADR. Several studies have assessed the effect of a comprehensive geriatric assessment and management on drug prescribing and drug related illness, showing a substantial improvement in quality of prescription and a reduction in rate of ADR. In addition, clinical guidelines providing recommendations regarding the use of drugs in chronic disease rarely assess the level of complexity observed in older adults and therefore they should be applied with caution in this population.