Buckling of Shape Memory Alloy Columns. 1st Report, Buckling of Curved Column and Twinning Deformation Effect.

雄太, 漆山; 進浩, 裘; 順二, 谷; Tani, Junji

doi:10.1299/kikaia.67.1132

Cited by 9 publications

(13 citation statements)

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“…They concluded that the transformation of typical SMA phases affected the solution to the problem. Finally, Richter et al [41] numerically analyzed the phenomenon so-called anti-buckling effect reported by Urushiyama et al [42] Table 1 shows the list of tests with the number of test speci-239 mens, the total bar length L total , the free length of each test L and mechanical slenderness L=k (where k ¼ D=4 and D is the bar diameter). A total of 30 steel bars and 6 Ni-Ti bars were tested.…”

Section: Introductionmentioning

confidence: 99%

Ni-Ti SMA bars behaviour under compression

Pereiro‐Barceló

Bonet

2017

Construction and Building Materials

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SMA (Shape Memory Alloys) is a type of material suitable for using in civil engineering as concrete rein-47 forcement because of their shape memory effect or superelasticity and their high ductility and damping 48 capacity. However, Ni-Ti alloys Young modulus could be 3 or 4 times lower than steel (200 GPa) depend-49 ing on the composition and thermal treatment, which can cause the instability of compressed bars. The 50 main objective of this work is to provide a modified constitutive model of SMA bars, particularized for Ni-51 Ti bars, that considers instability in compression. The inclusion of this effect in the constitutive equation 52 allows for simulating Ni-Ti bars under compression in a simple way as if they were perfectly straight bars. 53 To achieve this, six 12-mm diameter SMA bars made of Ni-Ti were tested under compression. The 54

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Section: Introductionmentioning

confidence: 99%

Ni-Ti SMA bars behaviour under compression

Pereiro‐Barceló

Bonet

2017

Construction and Building Materials

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“…Second, using SME structures and then applying external stress so that the mixtures of martensitic variants are forced to reorient into a single variant and generate inelastic strains. In the latter, the deformed shape of the structures can be recovered by applying axially compressive load; it is named ''Twinning Deformation effect'' (TD-effect) by Urushiyama et al (2003). The origin of this effect roots in the inhomogeneous stress states and mechanically induced twin-twin phase transformations (Richter et al, 2010;Urushiyama et al, 2003;Watkins and Shaw, 2018).…”

Section: Introductionmentioning

confidence: 99%

Analytical solution for twinning deformation effect of pre-strained shape memory effect beam-columns

Ostadrahimi

Taheri‐Behrooz

2019

Journal of Intelligent Material Systems and Structures

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In this article, an analytical solution is presented for twinning deformation effect of a prismatic shape memory alloy beam-column. To this end, a reduced one-dimensional Souza model is employed to study the bending stress of a pre-strained shape memory alloy beam-column at low temperatures. Analytical expressions for bending stress as well as polynomial approximations for deflection are obtained. Derived equations for bending problem are employed to analyze twinning deformation effect of shape memory alloy beam-columns with rectangular and circular cross sections. Furthermore, the distance of zero-stress fiber from the center line during loading is studied. The results of this work show good agreement when compared with experimental data and finite element results.

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“…Urushiyama et al (2003) experimentally examined the unbuckling-like behavior of SMA columns in the martensite phase. In their experiments, they used a three-step loading procedure to demonstrate unbuckling-like behavior: (1) a column was axially compressed in a load frame until the microstructure of the SMA material began to detwin, (2) the column was removed from the load frame and mechanically deformed into a “cosine” shape, and (3) the column was again installed into a load frame and axially compressed, resulting in straightening of the column (see Figure 1(c)).…”

Section: Introductionmentioning

confidence: 99%

“…Although the wrinkling problem has been studied for a number of years, Healey et al (2013) were the first to discover the unbuckling behavior of thin sheets analytically, which was later experimentally verified in polyethylene thin sheets by Nayyar et al (2014). Urushiyama et al (2003) experimentally examined the unbuckling-like behavior of SMA columns in the martensite phase. In their experiments, they used a three-step loading procedure to demonstrate unbuckling-like behavior:…”

Section: Introductionmentioning

confidence: 99%

“…While this disjoint loading procedure does not strictly satisfy our definition for unbuckling, since their columns were never buckled, steps (1) and (2) result in a configuration similar to a buckled column. It (a) Balloon inflation (adapted from [Alexander 1971]) (b) Sheet wrinkling in tension (adapted from [Nayyar et al 2014]) (c) Martensitic SMA column straightening (adapted from [Urushiyama et al 2003]) should also be noted that the mechanical behavior of SMAs in the martensite phase differs from that of superelastic SMAs (which are examined here), although both exhibit the seemingly necessary stiffening at large strains for unbuckling to occur. As a follow-up to this work, Richter et al (2011) used a finite element model to capture the behavior of SMA columns in the martensite phase, successfully simulating this straightening behavior during compression.…”

Section: Introductionmentioning

confidence: 99%

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Unbuckling of superelastic shape memory alloy columns

Watkins

Shaw

2018

Journal of Intelligent Material Systems and Structures

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Our recent buckling experiments on superelastic shape memory alloy columns (initially straight rods and tubes) discovered that during axial shortening, certain specimens bent (buckled) at a critical compressive load and then, surprisingly, straightened (unbuckled) at a larger compressive load. This “buckling–unbuckling” phenomenon, defined here as the deviation from and then return to a straight configuration during monotonic loading, is not only an intriguing phenomenon (contrary to the post-buckling behavior of conventional materials) but also presents the possibility for novel applications. This work aims to provide a clearer understanding of when and why unbuckling occurs, presenting the experimental observations of this phenomenon and the stability analysis of a modified Shanley column model that captures the unbuckling behavior. Unbuckling behavior is shown to be a consequence of a secondary branch that deviates from the principal path at a low-load level (critical buckling load), but reattaches to the principal path at a higher load level (unbuckling load). The analysis shows that unbuckling behavior can only occur for certain combinations of column geometries and nonlinear (stiff–soft–stiff) material laws, that is, relatively stout columns with the right sequence of softening/stiffening to create the necessary restorative bending moment to reset the column to a straight configuration. The feasible space is defined by closed-form bounds on geometric and material parameters, along with a sensitivity analysis of these parameters on the amplitude of unbuckling.

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Buckling of Shape Memory Alloy Columns. 1st Report, Buckling of Curved Column and Twinning Deformation Effect.

Cited by 9 publications

References 1 publication

Ni-Ti SMA bars behaviour under compression

Ni-Ti SMA bars behaviour under compression

Analytical solution for twinning deformation effect of pre-strained shape memory effect beam-columns

Unbuckling of superelastic shape memory alloy columns

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