On the improved adhesion of NiTi wires embedded in polyester and vinylester resins

Merlin, Mattia; Scoponi, Martina; Soffritti, Chiara; Fortini, Annalisa; Rizzoni, Raffaella; Garagnani, Gian Luca

doi:10.3221/igf-esis.31.10

Cited by 11 publications

(8 citation statements)

References 42 publications

(48 reference statements)

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“…Adhesion promotion by chemical treatments, on the other hand, relies on the introduction of new functional groups or compounds at the interface (often requiring removal of the native oxide layer and controlled passivation in the first step), providing for a chemical bond between the two materials. Several authors investigated the use of silane − and other chemical coupling agents/conversion coatings − to increase the bonding strength between the SMA wire surface and the polymer matrix. However, industrially applicable adhesion promoters such as chromate-based primers are of considerable concern with regard to their toxicity and carcinogenic hazards. , …”

Section: Introductionmentioning

confidence: 99%

Electrochemical Surface Structuring for Strong SMA Wire–Polymer Interface Adhesion

Gapeeva

Vogtmann

Zeller‐Plumhoff

et al. 2021

ACS Appl. Mater. Interfaces

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Active hybrid composites represent a novel class of smart materials used to design morphing surfaces, opening up new applications in the aircraft and automotive industries. The bending of the active hybrid composite is induced by the contraction of electrically activated shape memory alloy (SMA) wires, which are placed with an offset to the neutral axis of the composite. Therefore, the adhesion strength between the SMA wire and the surrounding polymer matrix is crucial to the load transfer and the functionality of the composite. Thus, the interface adhesion strength is of great importance for the performance and the actuation potential of active hybrid composites. In this work, the surface of a commercially available one-way effect NiTi SMA wire with a diameter of 1 mm was structured by selective electrochemical etching that preferably starts at defect sites, leaving the most thermodynamically stable surfaces of the wire intact. The created etch pits lead to an increase in the surface area of the wire and a mechanical interlocking with the polymer, resulting in a combination of adhesive and cohesive failure modes after a pull-out test. Consequently, the force of the first failure determined by an optical stress measurement was increased by more than 3 times when compared to the as-delivered SMA wire. The actuation characterization test showed that approximately the same work capacity could be retrieved from structured SMA wires. Moreover, structured SMA wires exhibited the same shape of the stress−strain curve as the as-delivered SMA wire, and the mechanical performance was not influenced by the structuring process. The austenite start A s and austenite finish A f transformation temperatures were also not found to be affected by the structuring process. The formation of etching pits with different geometries and densities was discussed with regard to the kinetics of oxide formation and dissolution.

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Section: Introductionmentioning

confidence: 99%

Electrochemical Surface Structuring for Strong SMA Wire–Polymer Interface Adhesion

Gapeeva

Vogtmann

Zeller‐Plumhoff

et al. 2021

ACS Appl. Mater. Interfaces

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“…The main purpose of using the NiTinol wire in composite is to carry the load applied to composite, while the matrix holds and protects the wire, thus distributing the load between them [10]. This curve before activation NiTinol wire is shown in figure (9).…”

Section: Results and Discussion 41 Results Of Experimental Workmentioning

confidence: 99%

“…Payandeh et al [9] investigated the effect of the transformation on the debonded inception in without pre-strained NiTinol wire-epoxy matrix composites. NiTinol wires were embedded in an epoxy coupon to achieve 6% and 12% NiTinol wires volume fractions.…”

Section: Introductionmentioning

confidence: 99%

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دراسة عملية وتحليل العناصر المحددة لتاثير التسخين على قوة الانسلاخ لسلك النيتينول مغمور داخل بولي اثيلين خطي منخفض الكثافة

Amin¹,

Hassan²

2018

alkej

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This study presents the debonding propagation in single NiTi wire shape memory alloy into linear low-density polyethylene matrix composite the study of using the pull-out test. The aim of this study is to investigate the pull-out tests to check the interfacial strength of the polymer composite in two cases, with activation NiTinol wire and without activation. In this study, shape memory alloy NiTinol wire 2 mm diameter and linear fully annealed straight shape were used. The study involved experimental and finite element analysis and eventually comparison between them. This pullout test is considered a substantial test because its results have a relation with behavior of smart composite materials. The pull-out test was carried out by a universal tensile test machine type (Laryee), load capacity (50 kN), and a test speed of 1mm/min. The finite elements modeling was performed by ANSYS V.15. The results of pull-out test showed that in the activation of NiTinol wire embedded in host matrix linear low-density polyethylene (LLDPE), the deboned force was about 74 N, but for the case without activation, it was about 106 N. Deboned shear stress for the case with activation was about 0.73 MPa, but for the case of without activation, it was about 1.05 MPa. ANSYS result for deboned shear stress in case with activation was about 0.8 MPa. As for the case of without activation, deboned shear stress was about 0.99 MPa. The activation of the ratio of deboned shear stress and deboned force decreased by 30.47% and 30.13%, respectively. The error ratio between experimental and ANSYS results was equal to 8% for the case with activation and 5.7% for the case without activation.

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“…In previous studies in which pull-out strength was studied [35,36], it was seen that the interface adhesion between the wire and the matrix was examined by pulling the wires from the composite structure. In this study, pull-out tests were accomplished on Shimadzu Universal Tensile Tester to investigate the pull-out strength of the wire core hybrid yarns from the 3D woven fabrics.…”

Section: Methodsmentioning

confidence: 99%

Development of 3D hollow woven fabrics with superior mechanical properties by using nitinol and steel wire core hybrid yarns

Yılmaz

Altaş

2020

Journal of Industrial Textiles

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In this study, nitinol and steel wire core hybrid yarns were produced from wires having two different diameters and used as warp yarns to weave 3D woven fabrics in two different fabric constructions. The steel bars with two different diameters were placed into the gaps between fabric layers to create a hollow form after fabric production. The fabrics produced with cold-worked nitinol wire were exposed to heat treatments at high temperatures to provide them shape memory property according to data obtained from DSC analysis. Conventional textile fibers are not durable to these temperatures; for this reason, carbon fiber was used both as sheath material of hybrid yarns and additionally as warp and weft carbon fiber yarns. All yarn and fabric tests were carried out simultaneously to evaluate the mechanical properties of nitinol and steel wire core hybrid yarns, and wire-reinforced fabrics. Tensile tests were applied to all wire and hybrid yarn samples, DSC and DMA analyses were conducted for only heat-treated nitinol wires. Low-velocity impact, tensile and pull-out tests were applied to fabric samples. Reference fabrics with no wire were produced and evaluated by comparing with wire-reinforced samples to provide a point of comparison to the data from the mechanical properties of wire-reinforced 3D fabrics. The study's results were analyzed with regression analysis using the backward method, and the parameters such as wire type, wire diameter, and fabric gap width for optimum fabric production were determined. Data obtained from all mechanical tests demonstrate that fabric samples with steel wire, thinner wire, and narrow gaps have better results than others. The effect of wire thickness was also found the same for the nitinol wire. DMA analyses show that the thinner nitinol wire is better than, the thicker one. Finally, an innovative technique has been developed in this study to weave carbon fiber on a conventional automatic sample loom without fiber breakage by twisting PVA yarn around the wire core hybrid and twisted carbon fiber yarns.

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On the improved adhesion of NiTi wires embedded in polyester and vinylester resins

Cited by 11 publications

References 42 publications

Electrochemical Surface Structuring for Strong SMA Wire–Polymer Interface Adhesion

Electrochemical Surface Structuring for Strong SMA Wire–Polymer Interface Adhesion

دراسة عملية وتحليل العناصر المحددة لتاثير التسخين على قوة الانسلاخ لسلك النيتينول مغمور داخل بولي اثيلين خطي منخفض الكثافة

Development of 3D hollow woven fabrics with superior mechanical properties by using nitinol and steel wire core hybrid yarns

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