This paper investigates the torsion analysis of coated bars with a rectangular cross-section. Two opposite faces of a bar are coated by two isotropie layers with different materials of the original substrate that are ...This paper investigates the torsion analysis of coated bars with a rectangular cross-section. Two opposite faces of a bar are coated by two isotropie layers with different materials of the original substrate that are perfectly bonded to the bar. With the Saint- Venant torsion theory, the governing equation of the problem in terms of the warping function is established and solved using the finite Fourier cosine transform. The state of stress on the cross-section, warping of the cross-section, and torsional rigidity of the bar are evaluated. Effects of thickness of the coating layers and material properties on these quantities are investigated. A set of graphs are provided that can be used to determine the coating thicknesses and material properties so as to keep the maximum von Mises stress on the cross-section below an allowable value for effective use of the coating layer.展开更多
Mechanical metamaterials are architectured cellular materials with unusual properties.Herein we report another type of metal mechanical metamaterials-their elastic admissible strain(EAS)is on the order of 0.1,compared...Mechanical metamaterials are architectured cellular materials with unusual properties.Herein we report another type of metal mechanical metamaterials-their elastic admissible strain(EAS)is on the order of 0.1,compared to about 0.01 for common metallic materials.Four conditions are required for a metal mechanical metamaterial to achieve this super EAS:(i)bending-dominated deformation;(ii)low density;(iii)an appropriate lattice topology,and(iv)an intrinsically high EAS for the lattice strut constituent material.The findings of this work extend perspectives on metal mechanical metamaterials.展开更多
In this work,the stress intensity factors(SIFs)for a wide range of semi-elliptical surface cracks with different inclination angles in a cylindrical bar subjected to pure tension were investigated numerically.The main...In this work,the stress intensity factors(SIFs)for a wide range of semi-elliptical surface cracks with different inclination angles in a cylindrical bar subjected to pure tension were investigated numerically.The main parameters considered to evaluate the SIFs were the crack size ratio(a/d),the crack aspect ratio(a/c),and the crack inclination angle(0).The dual-boundary element met hod implemented in software BEASY was used to compute the SIF values for cracks.Furt her more,the general closed-form solutions were proposed to evaluate the corresponding SIFs for Mode I,Mode II and Mode III types of fracture through curve fitting approaches.These solutions can provide accurate and reliable values of stress intensity factors for a crack on a cylindrical bar under pure tension in a rapid way compared to those obtained using computational models.In addition,these results can be used as inputs for failure studies and life evaluations of cracked cylinder under working conditions.展开更多
文摘This paper investigates the torsion analysis of coated bars with a rectangular cross-section. Two opposite faces of a bar are coated by two isotropie layers with different materials of the original substrate that are perfectly bonded to the bar. With the Saint- Venant torsion theory, the governing equation of the problem in terms of the warping function is established and solved using the finite Fourier cosine transform. The state of stress on the cross-section, warping of the cross-section, and torsional rigidity of the bar are evaluated. Effects of thickness of the coating layers and material properties on these quantities are investigated. A set of graphs are provided that can be used to determine the coating thicknesses and material properties so as to keep the maximum von Mises stress on the cross-section below an allowable value for effective use of the coating layer.
基金the China Scholarship Council(CSC)for a CSC scholarship(No.201706230108)Funding from the National Natural Science Foundation of China(No.51971145)and the Australian Research Council(Nos.DP200102666 and No.DE230101344)is acknowledged.
文摘Mechanical metamaterials are architectured cellular materials with unusual properties.Herein we report another type of metal mechanical metamaterials-their elastic admissible strain(EAS)is on the order of 0.1,compared to about 0.01 for common metallic materials.Four conditions are required for a metal mechanical metamaterial to achieve this super EAS:(i)bending-dominated deformation;(ii)low density;(iii)an appropriate lattice topology,and(iv)an intrinsically high EAS for the lattice strut constituent material.The findings of this work extend perspectives on metal mechanical metamaterials.
文摘In this work,the stress intensity factors(SIFs)for a wide range of semi-elliptical surface cracks with different inclination angles in a cylindrical bar subjected to pure tension were investigated numerically.The main parameters considered to evaluate the SIFs were the crack size ratio(a/d),the crack aspect ratio(a/c),and the crack inclination angle(0).The dual-boundary element met hod implemented in software BEASY was used to compute the SIF values for cracks.Furt her more,the general closed-form solutions were proposed to evaluate the corresponding SIFs for Mode I,Mode II and Mode III types of fracture through curve fitting approaches.These solutions can provide accurate and reliable values of stress intensity factors for a crack on a cylindrical bar under pure tension in a rapid way compared to those obtained using computational models.In addition,these results can be used as inputs for failure studies and life evaluations of cracked cylinder under working conditions.
