Topic

# Ultimate tensile strength

About: Ultimate tensile strength is a(n) research topic. Over the lifetime, 129285 publication(s) have been published within this topic receiving 2123768 citation(s). The topic is also known as: UTS & tensile strength.

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TL;DR: The tensile strengths of individual multiwalled carbon nanotubes (MWCNTs) were measured with a "nanostressing stage" located within a scanning electron microscope and a variety of structures were revealed, such as a nanotube ribbon, a wave pattern, and partial radial collapse.

Abstract: The tensile strengths of individual multiwalled carbon nanotubes (MWCNTs) were measured with a “nanostressing stage” located within a scanning electron microscope. The tensile-loading experiment was prepared and observed entirely within the microscope and was recorded on video. The MWCNTs broke in the outermost layer (“sword-in-sheath” failure), and the tensile strength of this layer ranged from 11 to 63 gigapascals for the set of 19 MWCNTs that were loaded. Analysis of the stress-strain curves for individual MWCNTs indicated that the Young's modulus E of the outermost layer varied from 270 to 950 gigapascals. Transmission electron microscopic examination of the broken nanotube fragments revealed a variety of structures, such as a nanotube ribbon, a wave pattern, and partial radial collapse.

4,691 citations

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Abstract: The fracture of ductile solids has frequently been observed to result from the large growth and coalescence of microscopic voids, a process enhanced by the superposition of hydrostatic tensile stresses on a plastic deformation field. The ductile growth of voids is treated here as a problem in continuum plasticity. First, a variational principle is established to characterize the flow field in an elastically rigid and incompressible plastic material containing an internal void or voids, and subjected to a remotely uniform stress and strain rate field. Then an approximate Rayleigh-Ritz procedure is developed and applied to the enlargement of an isolated spherical void in a nonhardening material. Growth is studied in some detail for the case of a remote tensile extension field with superposed hydrostatic stresses. The volume changing contribution to void growth is found to overwhelm the shape changing part when the mean remote normal stress is large, so that growth is essentially spherical. Further, it is found that for any remote strain rate field, the void enlargement rate is amplified over the remote strain rate by a factor rising exponentially with the ratio of mean normal stress to yield stress. Some related results are discussed, including the long cylindrical void considered by F.A. McClintock (1968, J. appl. Mech . 35 , 363), and an approximate relation is given to describe growth of a spherical void in a general remote field. The results suggest a rapidly decreasing fracture ductility with increasing hydrostatic tension.

3,769 citations

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05 Oct 2000

Abstract: 1. Introduction 2. Hardness measurements by spherical indenters 3. Deformation and indentation of ideal plastic metals 4. Deformation of metals by spherical indenters. Ideal plastic metals 5. Deformation of metals by spherical indenters. Metals which work-harden 6. Deformation of metals by spherical indenters. 'Shallowing' and elastic 'recovery' 7. Hardness measurements with conical and pyramidal indenters 8. Dynamic or rebound hardness 9. Area of contact between solids Appendix I. Brinell hardness Appendix II. Meyer hardness Appendix III. Vickers hardness Appendix IV. Hardness conversion Appendix V. Hardness and ultimate tensile strength Appendix VI. Some typical hardness values

3,492 citations

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Abstract: Necking and failure in a round tensile test specimen is analysed numerically, based on a set of elastic-plastic constitutive relations that account for the nucleation and growth of micro-voids. Final material failure by coalescence of voids, at a value of the void volume fraction in accord with experimental and computational results, is incorporated in this constitutive model via the dependence of the yield condition on the void volume fraction. In the analyses the material has no voids initially; but high voidage develops in the centre of the neck where the hydrostatic tension peaks, leading to the formation of a macroscopic crack as the material stress carrying capacity vanishes. The numerically computed crack is approximately plane in the central part of the neck, but closer to the free surface the crack propagates on a zig-zag path, finally forming the cone of the cup-cone fracture. The onset of macroscopic fracture is found to be associated with a sharp “knee” on the load deformation curve, as is also observed experimentally, and at this point the reduction in cross-sectional area stops.

2,645 citations

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TL;DR: The mechanical response of 15 single wall carbon nanotube (SWCNT) ropes under tensile load was measured and strain data were obtained and they broke at strain values of 5.3% or lower.

Abstract: The mechanical response of 15 single wall carbon nanotube (SWCNT) ropes under tensile load was measured. For 8 of these ropes strain data were obtained and they broke at strain values of $5.3%$ or lower. The force-strain data are well fit by a model that assumes the load is carried by the SWCNTs on the perimeter of each rope. This model provides an average breaking strength of SWCNTs on the perimeter of each rope; the 15 values range from 13 to 52 GPa (mean 30 GPa). Based on the same model the 8 average Young's modulus values determined range from 320 to 1470 GPa (mean 1002 GPa).

2,431 citations