Characterization of NiTi Shape Memory Damping Elements designed for Automotive Safety Systems

Strittmatter, Joachim; Clipa, Victor; Gheorghita, V.; Gümpel, Paul

doi:10.1007/s11665-014-1045-1

Cited by 8 publications

(4 citation statements)

References 19 publications

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“…Although the martensitic transformation has the most significant impact on the functional properties of alloys, other microstructural defects such as dislocations, vacancies, etc. can cause significant changes [ 8 , 9 ].…”

Section: Introductionmentioning

confidence: 99%

“…Hysteresis observed in pseudoelasticity is one of the energy dissipation manifestations [ 8 ]. According to the results of Wu et al [ 10 ], in Cu-xZn-11Al (x = 7.0, 7.5, 8.0, 8.5, and 9.0 wt.%), a higher amount of martensite is transformed during martensite transformation, so the alloy exhibits a higher amount of energy dissipation due to higher hysteresis.…”

Section: Introductionmentioning

confidence: 99%

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The Effect of Heat Treatment on Damping Capacity and Mechanical Properties of CuAlNi Shape Memory Alloy

et al. 2022

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This paper discusses the effect of different heat treatment procedures on the microstructural characteristics, damping capacities, and mechanical properties of CuAlNi shape memory alloys (SMA). The investigation was performed on samples in the as-cast state and heat treated states (solution annealing at 885 °C/60’/H2O and after tempering at 300 °C/60’/H2O). The microstructure of the samples was examined by light microscopy (LM) and scanning electron microscopy (SEM) equipped with a device for energy dispersive spectrometry (EDS) analysis. Light and scanning electron microscopy showed martensitic microstructure in all investigated samples. However, the changes in microstructure due to heat treatment by the presence of two types of martensite phases (β1’ and γ1’) influenced alloy damping and mechanical properties by enhancing alloy damping characteristics. Heat treatment procedure reduced the alloys’ mechanical properties and increased hardness of the alloy. Fractographic analysis of the alloy showed a transgranular type of fracture in samples after casting. After solution annealing, two types of fracture mechanisms can be noticed, transgranular and intergranular, while in tempered samples, mostly an intergranular type of fracture exists.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

The Effect of Heat Treatment on Damping Capacity and Mechanical Properties of CuAlNi Shape Memory Alloy

et al. 2022

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“…The potential of SMA fibers to enhance the damping capacity and toughness of composite materials has also been investigated in several works [19][20][21][22]. In [21] epoxy resin composites filled with Ni-Ti alloy short fibers were developed and their dynamic mechanical properties were investigated; the results showed that the vibration characteristics are significantly affected largely by the presence of small amount of SMA fibers.…”

Section: Introductionmentioning

confidence: 99%

Improving the damping behavior of fiber-reinforced polymer composites with embedded superelastic shape memory alloys (SMA)

Katsiropoulos

Pappas

Koutroumanis

et al. 2019

Smart Mater. Struct.

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One-way shape memory alloy wires exhibiting super elastic properties are capable of generating high recovery stresses under constrained conditions upon external mechanical loading. In the present work, the damping response of hybrid composite materials enhanced with super-elastic NiTi alloy wires is examined. The studied system consisted of an aramid reinforced epoxy resin composite in which NiTi wires have been embedded. By conducting damping measurements it was found that the addition of Ni-Ti wires into the aramid/epoxy composite leads to a significant modification of its damping which depends strongly on wire volume fraction. This paves the way for the design of a new class of hybrid materials that combine the stiffness and strength of reinforcing fibers with the increased damping tuning capability offered by the NiTi wires.

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“…In the past years we have seen an increasing use of NiTi shape memory alloys in applications, such as: biomedical [1], automotive [2] and aerospace [3]. Some of these applications require the use of complex shapes, which are not easy to obtain due to the difficult machinability of NiTi.…”

Section: Introductionmentioning

confidence: 99%

High strain and long duration cycling behavior of laser welded NiTi sheets

Oliveira

Miranda

Schell

et al. 2016

International Journal of Fatigue

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The use of NiTi in complex shaped components for structural applications is limited by the material cost and machinability and adequate joining techniques have been investigated to minimize the thermal cycle effect on the superelastic and shape memory effects exhibited by NiTi. Laser welding is the most used joining process for this material. However, existing studies mainly address the functional properties of laser welded NiTi wires, and the superelastic cycling tests are limited to either a low number of cycles (maximum 100) or to low strains (below 6%). This paper discusses the results of the cycling behavior exhibited by laser butt welded 1 mm thick NiTi plates, when tested to high strains (up to 10%) and for a large number of cycles (600). The superelastic effect was observed and the microstructural changes induced by the laser welding procedure, namely the extension of the thermal affected regions, were seen to influence the evolution of the accumulated irrecoverable strain. Thus, it is possible, by controlling the heat input introduced during welding, to tune the maximum superelastic recovery presented by NiTi laser welds.Keywords: NiTi; Shape memory alloys; Laser welding; High strain cycling; Superelasticity. Graphical abstract 2 Highlights Cycling at high strains and for a high number of cycles was performed on laser welded NiTi sheets. This is the first study of this kind.  Process parameters influence the superelastic recovery. Lower heat input implies lower irrecoverable strain.  Welded samples were successfully load/unloaded 600 times, 110 to 130 MPa below their ultimate tensile strength.  Martensite in the thermal affected regions is responsible to lower the superelastic plateau of the welds.

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Characterization of NiTi Shape Memory Damping Elements designed for Automotive Safety Systems

Cited by 8 publications

References 19 publications

The Effect of Heat Treatment on Damping Capacity and Mechanical Properties of CuAlNi Shape Memory Alloy

The Effect of Heat Treatment on Damping Capacity and Mechanical Properties of CuAlNi Shape Memory Alloy

Improving the damping behavior of fiber-reinforced polymer composites with embedded superelastic shape memory alloys (SMA)

High strain and long duration cycling behavior of laser welded NiTi sheets

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