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Showing papers on "Torsion (mechanics) published in 2022"


Journal ArticleDOI
TL;DR: In this paper, a higher-order unified gradient elasticity theory is conceived in a mixed variational framework based on suitable functional space of kinetic test fields, and the intrinsic form of the differential and boundary conditions of equilibrium along with the constitutive laws is consistently established.

51 citations


Journal ArticleDOI
TL;DR: In this paper, a generalised neo-Hookean strain energy function within the family of limiting chain extensibility models was proposed for the problem of torsion in incompressible isotropic rubber-like tubes and solid circular cylinders.
Abstract: In this paper we demonstrate the application of a newly proposed generalised neo-Hookean strain energy function within the family of limiting chain extensibility models to the problem of torsion in incompressible isotropic rubber-like tubes and solid circular cylinders. We consider a general deformation involving extension and torsion in tubes, and subsequently specialise to the simple torsion of solid cylinders. Expressions for the twisting moment M , axial load N and the inflation pressure P are derived and presented for all the considered deformations. Using the proposed model, solutions are obtained for the critical axial stretch λ c z beyond which the specimens exhibit the reversal of the Poynting-type effect upon twisting for both stretched tubes and solid cylinders. The model is then applied to various existing experimental datasets involving torsion in tubes and cylinders. By simultaneous fitting of the model to the considered datasets, it is shown that the model favourably captures the torsional deformation of rubber-like materials. Furthermore, it will be demonstrated that the response function of the model is compatible with Penn and Kearsley's scaling law in torsion and can be directly derived from the ensuing experimental data. While the problem of torsion in elastic tubes and cylinders has been well-studied, this work provides a contribution to nuanced aspects of this problem including the prediction of the critical axial stretch λ c z at which Poynting-type effects reverse in stretched specimens, demonstration of compatibility with the scaling law and favourable simultaneous fits to a variety of experimental datasets involving the torsion of tubes and solid cylinders.

16 citations


Journal ArticleDOI
TL;DR: The proposed event-triggered control method is feasible for PDE models and has good control effect while reduce signal transmission and the stability and convergence of the closed-loop system are proved via Lyapunov's direct method.

9 citations



Journal ArticleDOI
TL;DR: In this article, a cylindrical nematic elastomer balloon under the combined action of axial tension and inflating pressure has been investigated, and the balloon exhibits a variety of torsion and bulging performances.
Abstract: The liquid crystal mesogens in a nematic elastomer film under simple uniaxial tension may reorientate and in turn lead to shear of the film. This shear effect under simple loading has potential applications in artificial muscles, micro nano devices, biomedical instruments and other fields. When a nematic elastomer film is fabricated into a cylindrical balloon as a pneumatic artificial muscle, it has presented abnormal inflation behaviors including inflation-induced axial contraction. During the inflation process, the nematic elastomer balloon may also have shear/torsion effect due to the reorientation of the helically distributed liquid crystal mesogens. Based on the nematic elastomer theory proposed by Bladon et al., the torsion and bulging of a cylindrical nematic elastomer balloon under the combined action of axial tension and inflating pressure are theoretically investigated in this paper. In the cases of different axial tensions, the inflation process of the balloon shows a variety of torsion and bulging performances. The initial mesogen director also has a great influence on its torsion and bulging behaviors. The results of this paper further deepen the understanding of the inflation behaviors of a nematic elastomer balloon, and provide guidance for its applications in artificial muscles, soft robots and other fields.

5 citations


Journal ArticleDOI
TL;DR: In this article, a seven-core fiber torsion sensor with microcavity structure based on intensity measurement is proposed, which is composed of a seven core fiber and two multi-mode fibers.

4 citations


Journal ArticleDOI
TL;DR: In this article, the plastic flow of hollow cylinders under combining axial compression with torsion was examined in upsetting and in lateral extrusion and it was found that the enhancement of plastic flow in upsetting was applied to fill up tooth cavity.

3 citations


Journal ArticleDOI
TL;DR: In this article, a novel experimental set-up is proposed to perform in-plane torsion experiments on grooved disk specimens, where a custom-made washer-nut system is used which allows for the monitoring of the entire specimen front surface with cameras.

2 citations



Journal ArticleDOI
TL;DR: In this article, a one-dimensional technical theory for pretwisted isotropic linearly elastic beams loaded in tension and torsion was developed, based on a kinematically admissible field.
Abstract: A one-dimensional technical theory for pretwisted isotropic linearly elastic beams loaded in tension and torsion was developed. The analysis was based on a kinematically admissible field wr...

1 citations


Journal ArticleDOI
TL;DR: In this article, a crystal plasticity-continuum dislocation dynamics modeling effort was performed to predict the mechanical performance of cylindrical copper samples by using electron backscatter diffraction and performing Vickers hardness/tensile testing.
Abstract: Severely plastically deformed microstructures of pure copper were produced by subjecting cylindrical copper samples to high-pressure torsion. The effects of this procedure on introducing gradient microstructure and subsequent mechanical behavior were investigated by utilizing electron backscatter diffraction and performing Vickers hardness/tensile testing. A crystal plasticity-continuum dislocation dynamics modeling effort was performed to predict the mechanical performance of these samples. The model includes mechanisms based on the gradient of dislocation density and grain size, back stress fields of grain boundaries, dislocation density transmission across grain boundaries, and stress/strain gradient effects.


Journal ArticleDOI
TL;DR: Based on the characteristics of the ribbon structure, the dynamic mathematical model of the arched ribbon driven by torsion is established from the Kirchhoff rod equation in this paper, where the variations of the Euler angle of each point on the center line of a ribbon with the arc coordinate s and the rotation angle of the supports ϕ were examined.
Abstract: The morphological transformation of an arched ribbon driven by torsion is a scientific problem that is connected with daily life and requires thorough analysis. An arched ribbon can achieve an instantaneous high speed through energy transformation and then return to the original shape of the structure. In this paper, based on the characteristics of the ribbon structure, the dynamic mathematical model of the arched ribbon driven by torsion is established from the Kirchhoff rod equation. The variations of the Euler angle of each point on the center line of the ribbon with the arc coordinate s and the rotation angle of the supports ϕ was examined. The relationship between the internal force distribution of each point in the direction of d ˆ a and the material, cross-sectional properties, and rotation angle of the supports was obtained. We used ABAQUS, a nonlinear finite element analysis tool, to simulate the morphological transformations of the ribbons, verified our theory with simulation results, and reproduced the experimental results of Sano. Furthermore, we redefined the concept of the “critical flipping point” of Sano. In this paper, the dimensional analysis method was used to fit the simulation data. The following relationship between the critical width w ∗ , thickness h , and the radius R of the ribbon with different cross sections was obtained: w ∗ = A ⋅ R h / R 0 . 6 , where A is 3.19 for rectangular cross sections and 3.06 for elliptical cross sections. By analyzing the simulation data, we determined the variation behavior of the out-of-plane deflection of the center point of the ribbon with the radius R , width w , and thickness h . Our research has guiding significance for understanding and designing arched ribbons driven by torsion, and the results can be applied to problems of different scales.

Book ChapterDOI
01 Jan 2022
TL;DR: In this article, four inclination angles of stirrups (80°, 75°, and 45°) and traditional (90°) kinds of Stirrups are adopted in beams, namely B1, B2, B3, and B4.
Abstract: In this present study, four inclination angles of stirrups (80°, 75°, and 45°) and traditional (90°) kinds of stirrups are adopted in beams, namely B1, B2, B3, and B4. The analytical study is done using finite element software program the usage of ABAQUS. The present study investigated load versus deflection, stiffness, and torque versus the angle of twist. The analytical results are compared with theoretical results by using ACI and MacGregor methods. Based on analytical and theoretical results compared to conventional 90° stirrups (B1), specimen 45° and 75° show that the increase in load-carrying capacity and the deflection was observed in 0.001 mm. Compared to other types of stirrups (90°, 80°, and 45°), the maximum stiffness observed at 75° stirrups specimen (B3) is 6068.18 kN/m. Furthermore, specimen B3 (75°) resists nearly 81% of the angle of twist for the applied torque compared to 90° stirrups specimen (B1).