Thermomechanical Characterization of Superelastic Ni-Ti SMA Helical Extension Springs Manufactured by Investment Casting

Santiago, José Joelson de Melo; Simões, Jackson de Brito; Araújo, Carlos José de

doi:10.1590/1980-5373-mr-2018-0852

Cited by 4 publications

(3 citation statements)

References 27 publications

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“…The FE correction factors for these three locations were obtained by substituting the maximum shear stress in the body and section B as well as the combination of bending and normal stresses into Equations (1), (4) and (6). The corresponding correction factors of the spring body and points A and B were then calculated by using Equations (3), (5) and 7, respectively.…”

Section: Simulation Validationmentioning

confidence: 99%

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Investigation on the Curvature Correction Factor of Extension Spring

et al. 2020

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The curvature correction factor is an important parameter in the stress calculation formulation of a helical extension spring, which describes the effect of spring wire curvature on the stress increase towards its inner radius. In this study, the parameters affecting the curvature correction factor were investigated through theoretical and numerical methods. Several finite element (FE) models of an extension spring were generated to obtain the distribution of the tensile stress in the spring. In this investigation, the hook orientation and the number of coils of the extension spring showed significant effects on the curvature correction factor. These parameters were not considered in the theoretical model for the calculation of the curvature correction factor, causing a deviation between the results of the FE model and the theoretical approach. A set of equations is proposed for the curvature correction factor, which relates both the spring index and the number of coils. These equations can be applied directly to the design of extension springs with a higher safety factor.

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Section: Simulation Validationmentioning

confidence: 99%

“…Extension springs are extensively used in many industrial applications, such as in several parts and instruments in automotive, aerospace, robotics and machinery industries, in which spring failure could cause the failure of a whole system [1][2][3][4]. Extension springs are a part of the helical spring family.…”

Section: Introductionmentioning

confidence: 99%

Investigation on the Curvature Correction Factor of Extension Spring

et al. 2020

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“…1–3 The process by which SMA produces shape memory effect is that loading SMA transforms the austenite phase to stable non-twinned martensite phase when SMA is below the austenite phase transition temperature, heating SMA after unloading brings it to the austenite phase finish transition temperature, SMA reverses from non-twinned martensite to austenite phase and macroscopically shows that deformation gradually recovers after SMA heating. 4–6 Smart components made of SMA-based shape memory effect are widely used in medical, 7,8 control, 9,10 mechanical, 11,12 and Aerospace. 13,14…”

Section: Introductionmentioning

confidence: 99%

Thermomechanical performance analysis and experiment of electrothermal shape memory alloy helical spring actuator

Xiong

Huang

Shu

2021

Advances in Mechanical Engineering

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In this paper, an electrothermal shape memory alloy helical spring actuator constructed from shape memory alloy with copper-cored enameled wire is presented and fabricated. Based on the shear constitutive model of a shape memory alloy, the Thermo equilibrium equation and the geometrical equation of helical spring establish the thermomechanical theoretical model of helical spring actuator with electrothermal shape memory alloys under different scenarios. The thermomechanical behaviors of the actuator were verified by numerical simulation with experimental tests, and the actuator thermomechanical properties were derived from the analysis with current, temperature, response time, restoring force, and axial displacement as parameters. The experimental results show that the actuator produces a maximum recovery force of 70.2 N and a maximum output displacement of 7.7 mm at 100°C. The actuator response time is 26 s at a current of 3A. It is also demonstrated that the theoretical model can effectively characterize the complex thermo-mechanical properties of the actuator due to the strong nonlinearity of the shape memory alloy. The experimental temperature-force response and temperature-displacement response, as well as the force-displacement response at different temperatures, provide references for the design and fabrication of electrothermal shape-memory alloy coil spring actuators.

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Mechanical behavior of a NiTi superelastic bone plate obtained by investment casting assisted by additive manufacturing

Gomes¹,

Grassi²,

Silva³

et al. 2020

Smart Mater. Struct.

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The mechanical behavior of nickel-titanium shape memory alloys (NiTi SMA) presents unique features that benefit the bone fracture healing process: matching elastic modulus ranges, the ability to recover large deformations, and mechanical dissipation capacity. In this sense, this work proposes a new manufacturing process for NiTi SMA bone implants, particularly bone plates: additive manufacturing assisted investment casting (IC). This process delivers near-net NiTi SMA parts with either simple or complex shapes, also allowing a high degree of customization. Four identical NiTi SMA bone plates were manufactured through IC and characterized. Four-point bending tests were performed on the bone plate prototypes to verify their mechanical and fatigue behaviors. The NiTi bone plates have an elastic modulus of the order of 49 GPa at 37 °C and recovered all deformations upon unloading when submitted to four-point bending deflections up to 4 mm. The fatigue life was between 103 and >105, depending on the deflection amplitude. Our next work with this technology will address aspects of cytotoxicity and implantation of the part in animals.

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Thermomechanical Characterization of Superelastic Ni-Ti SMA Helical Extension Springs Manufactured by Investment Casting

Cited by 4 publications

References 27 publications

Investigation on the Curvature Correction Factor of Extension Spring

Investigation on the Curvature Correction Factor of Extension Spring

Thermomechanical performance analysis and experiment of electrothermal shape memory alloy helical spring actuator

Mechanical behavior of a NiTi superelastic bone plate obtained by investment casting assisted by additive manufacturing

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