Shape memory alloy (SMA) helical springs are special mechanical parts that require a previous evaluation of its behavior for application. Therefore, in this paper thermal and mechanical behaviour of superelastic Ni-Ti SMA helical extension springs manufactured by investment casting (IC) are evaluated. Phase transformation temperatures were measured by Electrical Resistance as a function of Temperature (ERT) and Differential Scanning Calorimetry (DSC). Tensile tests were carried out within strain and temperatures ranges. The pitch angle and stiffness of each spring were determined. Results demonstrated that Ni-Ti SMA helical springs produced by IC presented phase transformation corresponding to the superelastic effect (SE). The reversible deformations under tensile test were of the order of 70%. The mechanical behavior as function of temperature revealed a linear relationship between maximum force and spring temperature.

This paper presents a thermal and microstructural characterization of Cu87-xAl13Nbx (wt%) high temperature shape memory alloys (HTSMA), with Nb contents ranging from 1 to 3%. The alloys were obtained by arc melting under argon atmosphere. Thermal characterization was performed by differential scanning calorimetry (DSC), revealing that the phase martensitic transformation of all the studied alloys occurs in the range of 200 ºC to 450 ºC. Thermal cycling in this temperature range caused the martensitic transformation to disappear after approximately 6 cycles. However, a new heat treatment at 850 ºC followed by water quenching causes the martensitic transformation to be recovered. Microstructural characterization was performed using optical microscopy (OM) and scanning electron microscopy (SEM), revealing the presence of Nb precipitates in a Cu-Al martensitic matrix, mainly in the Nb-rich compositions. These different microstructures with Nb particles cause a hardness variation that initially decreases between 0.5 %Nb (275HV) and 1.0 %Nb (225HV), then increasing continuously up to 3.0% Nb (380HV).

With the growing human awareness of trying to reduce the environmental impact in today’s world, the development of new sustainably based materials has been the increasing focus of industry and academia. Biocomposites are environmentally friendly materials produced from raw materials synthesized from renewable sources. In this sense, this work aims to characterize and evaluate the mechanical and thermal performances of biocomposites manufactured from a thermoplastic matrix of high-density bioethylene and obtained from ethanol produced from sugarcane and reinforced with organophilic montmorillonite clay. For this, polyethylene grafted with maleic anhydride (PE-g-MA) was used as a compatibilizer. Dry biocomposites with 1, 3, and 5% organophilic montmorillonite clay, by weight, were subjected to structural (FTIR and DRX), thermal (DSC), thermogravimetric (TG/DTG), thermodynamic–mechanical (DMA), morphological (SEM and MET), and mechanical (tensile, flexural, impact, and shore D hardness tests) characterizations. The DMA experiments were carried out within the viscoelastic region of the polymer. From the obtained results, we notice that, in general, there was an increase in the properties of high-density biopolyethylene (B-HDPE) (without compromising its processability), and therefore, the automotive application of biocomposites compatible with PE-g-MA, containing low levels of organophilic montmorillonite clay, is recommended.

O ensino de engenharia tem adotado metodologias ativas para integrar teoria e prática na resolução de problemas reais. O Programa Baja SAE Brasil exemplifica essa abordagem, desafiando estudantes a projetar veículos off-road com sistemas mecânicos, elétricos e eletrônicos, promovendo o "aprender fazendo" e desenvolvendo competências técnicas e comportamentais. Assim, o objetivo desse artigo é apresentar o projeto de um sistema eletrônico baseado em Arduino para monitoramento da temperatura e velocidade angular da CVT, da velocidade linear do veículo e do acionamento 4x4, servindo como recurso pedagógico para projetos similares. Este trabalho envolveu projeto de placas de circuito impresso, programação para processamento em tempo real e validação experimental, utilizando exclusivamente softwares gratuitos. Os resultados demonstraram alta precisão e confiabilidade operacional, com erros inferiores a 1,5% e 0,12% nos módulos de temperatura e velocidade, respectivamente. A interface gráfica com barras coloridas permitiu leitura intuitiva dos parâmetros críticos durante as competições. Tais resultados evidenciam que o sistema é robusto, viável e pedagogicamente eficaz para o ensino de sistemas embarcados, com potencial uso no Programa Baja SAE.

The tireless quest for better living conditions makes people use technological resources as manners to balance a work/economy/safety relationship. Those technological resources have been applied more frequently in engineering. This is due to development of simulation software in order to provide greater economic viability in engineering projects. The considerable growth in the infrastructure market, further promoted the application of beams in projects, linked to this is the concern with the deformations that are caused to them. In this sense, the deformation suffered by a beam was evaluated via structure analysis using the ANSYS Mechanical software. The beam is at one extremity and supported by fixed support at the other extremity. To obtain the values of deformations a beam was developed in ANSYS, and after, the deformation was found through finite element methods. To verify the methodology effectiveness proposed in this study the numerical results were compared to data obtained in the tests and theoretical calculations. Through the values obtained, it was concluded that the values obtained in the simulation present deformations very similar to the tests and the theoretical calculation.