Smart materials are a class of materials characterized by having a different behavior due to external stimulation, which can be mechanic, thermal, electric, or magnetic. This chapter approaches the different types of smart materials and their classification according to the material’s nature (fluid, ceramic, polymeric and metallic). Emphasis is given to the theoretical study of the metallic materials with shape memory, presenting the fundamentals, crystallographic study and the mathematical methods of phase transformation. Due to these metallic material’s unique features, shape memory effect and super elasticity, the usage in the production of composite structures has gained space. Such materials present several advantages if compared to traditional composites being subject of research for several industrial applications
Shape memory alloys (SMA) are materials with metallic characteristic able to recover a geometric shape previously established under heat effect. This differentiated property, combined with the mechanical characteristic allows its use in many industrial situations. Active composites are produced with the polymeric matrix and wire of shape memory alloy, combining the elastic properties of the composite and characteristics of the phase transformation, martensite and austenite of SMA with memory alloy effect. The phase transformations that occur in the alloy are thermal processes, characterized by an increase in temperature during processing. The heat is transmitted for matrix, resulting in loss of mechanical properties of the composite. In this context, this paper aims to numerically analyze heat transfer in an epoxy resin polymer matrix incorporating Ni-Ti alloy wire with shape memory effect using ANSYS CFX software.
SMART materials have gained several applications in industries, especially aeronautical and biomedical. Therefore, the fabrication process of these materials must present quality in the completion and dimensioning, in addition to well established mechanical properties. In this sense, the Resin Transfer Molding (RTM) process is presented as an alternative to the manufacture of such products. This process presents advantages compared to other methods, such as, product quality and low cost. Thus, this work aims to model and simulate numerically the manufacturing process of polymer composite reinforced with NiTi shape memory alloy by RTM using the Ansys CFX commercial software. Results of pressure, velocity and volume fractions fields of the phases are presented and discussed. It was verified that the process parameters, like injection pressure and resin inlet and air outlet positions influenced the total time of the process and final product quality.
The paper presents an algorithm for read common numbers until one million in Portuguese language. The record and cutting process of the digit speech sounds deserved a special attention to improve the speech sound output. A special attention is required for the correct inclusion of the particle ‘e' (and) to provide better naturalness of the read numbers. The system has the ability of simulate the human biologic speech sound production in the task of reading numbers. The system is based in the concatenation of carefully recorded edited and selected speech segments corresponding to the digits. The naturalness of the system was improved with the use of speech files of read digits in different positions (beginning, middle and end) and using digits concatenated with the particle ‘e' before, after and before and after the digit.
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