Research on Nonlinear Damping Characteristics of Damping Alloy With Uniform Stress Field

For the high damping metal material like damping alloy, the damping capacity usually changes with the strain amplitude and frequency nonlinearly. First, to extract the pattern of the internal damping versus strain, two time-domain calculation methods are presented in this paper. One is the moving exponent method (MEM for short) based on FFT (MEM+FFT) and the other is the moving autoregressive model method (MARM). The computing accuracy of the two methods has been compared through numerical simulations. The nonlinear relation curve of loss factor versus strain is achieved by the impulse excitation experiment employing uniform stress field. Then, to extract the pattern of the internal damping versus vibrating frequency, the sine sweep-frequency excitation experiment based on the half-power bandwidth method is carried out. The resulting curve indicates that the internal damping is also a nonlinear function of frequency.

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New Methods for Nonlinear Damping Identification of Damping Alloy

Journal of Vibration and Acoustics ◽

10.1115/1.2748460 ◽

2007 ◽

Vol 129 (5) ◽

pp. 678-684 ◽

Cited By ~ 4

Author(s):

Ziying Wu ◽

Hongzhao Liu ◽

Lilan Liu ◽

Daning Yuan

Keyword(s):

Stress Field ◽

Autoregressive Model ◽

Nonlinear Behavior ◽

Nonlinear Damping ◽

Internal Damping ◽

New Methods ◽

Uniform Stress Field ◽

Nonuniform Stress Field ◽

Nonlinear Internal Damping ◽

Versus Strain

This paper presents two methods for the identification of nonlinear internal damping of alloy. One is the moving autoregressive model (MARM) method, and the other is the time-varying autoregressive model (TVARM) method. These procedures have been successfully implemented on two numerical examples. Comparison between simulation results demonstrates that the computation accuracy of the TVARM method is higher than that of the MARM method. In the experiments, the internal damping properties of the alloy Al-33Zn-6Si are researched, employing the rectangle beam with a nonuniform stress field and the trapezoid beam with a quasi-uniform stress field, respectively. Experimental results show that the internal damping of the alloy increases with the increasing strain and appears a nonlinear behavior. Moreover, the damping values of the trapezoid beam are relatively higher than those of the rectangle beam. Compared to the MARM method, the TVARM method can give a better description of nonlinear damping because the relation curve of loss factor versus strain obtained by the TVARM method is smoother than that obtained by the MARM method.

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Achieving a uniform stress field in a coated non-elliptical inhomogeneity in the presence of a mode III crack

Zeitschrift für angewandte Mathematik und Physik ◽

10.1007/s00033-018-1032-8 ◽

2018 ◽

Vol 69 (6) ◽

Author(s):

Xu Wang ◽

Liang Chen ◽

Peter Schiavone

Keyword(s):

Stress Field ◽

Uniform Stress ◽

Mode Iii ◽

Mode Iii Crack ◽

Elliptical Inhomogeneity ◽

Uniform Stress Field

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The 〈111〉 Elliptic Inclusion in an Anisotropic Solid of Cubic Symmetry

Journal of Applied Mechanics ◽

10.1115/1.3162093 ◽

1982 ◽

Vol 49 (2) ◽

pp. 353-360 ◽

Cited By ~ 1

Author(s):

H. C. Yang ◽

Y. T. Chou

Keyword(s):

Stress Field ◽

Uniform Stress ◽

Elliptic Inclusion ◽

Cubic Symmetry ◽

Elastic Fields ◽

Closed Form Solutions ◽

Strain Transformation ◽

Anisotropic Solid ◽

Uniform Stress Field ◽

Free Strain

This paper deals with a generalized plane problem in which a uniform stress-free strain transformation takes place in the region of an elliptic cyclinder (the inclusion) oriented in the 〈111〉 direction in an anisotropic solid of cubic symmetry. Closed-form solutions for the elastic fields and the strain energies are presented. The perturbation of an otherwise uniform stress field due to a 〈111〉 elliptic inhomogeneity is also treated including two extreme cases, elliptic cavities and rigid inhomogeneities.

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Uniform stress field inside an anisotropic non-elliptical inhomogeneity interacting with a screw dislocation

European Journal of Mechanics - A/Solids ◽

10.1016/j.euromechsol.2018.01.008 ◽

2018 ◽

Vol 70 ◽

pp. 1-7 ◽

Cited By ~ 5

Author(s):

Xu Wang ◽

Liang Chen ◽

Peter Schiavone

Keyword(s):

Stress Field ◽

Screw Dislocation ◽

Uniform Stress ◽

Elliptical Inhomogeneity ◽

Uniform Stress Field

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Atomic transport via point defects in crystals III. Migration in a stress field

Proceedings of the Royal Society of London Series A - Mathematical and Physical Sciences ◽

10.1098/rspa.1985.0031 ◽

1985 ◽

Vol 398 (1814) ◽

pp. 203-208 ◽

Cited By ~ 3

Keyword(s):

Stress Field ◽

Point Defects ◽

Strain Tensor ◽

Three Dimensional ◽

Molecular Volume ◽

Uniform Stress ◽

Atomic Transport ◽

Elastic Dipole ◽

Uniform Stress Field ◽

Defect Species

The kinetic theory of isothermal atomic transport via point defects that was presented in two previous papers (Franklin, A. D. & Lidiard, A. B. Proc. R. Soc. Lond . A 389, 405–431 (1983) and Franklin, A. D. & Lidiard, A. B. Proc. R. Soc. Lond . A 392, 457–473 (1984)) has been expanded into a three-dimensional formulation to analyse transport in an applied non-uniform stress field. The fluxes of the various defect species take the general form familiar from non-equilibrium thermodynamics, while the contribution to the force on defect species Y arising from the stress σ αβ is confirmed to be v ∇(λ (Y) αβ σ αβ ), where v is the molecular volume of the solid and λ (Y) αβ is the elastic-dipole strain tensor of the defect species Y (summation over repeated Cartesian indices α, β is here assumed). Full details of these calculations are presented in Lidiard, A. B. A. E. R. E. Rep . no R. 11367 (1984).

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