The Journal of Strain Analysis for Engineering Design, 2008
The laser-based interferometric strain—slope rosette (ISSR) has been used to measure principal st... more The laser-based interferometric strain—slope rosette (ISSR) has been used to measure principal strains and stresses on material surfaces. In this paper, optical theory models and computer programs are developed to simulate the optical diffraction and interference of the ISSR. The simulation results compare with the experimental results. Then the feasibility of extending the ISSR into a nanoscale rosette is studied. The indentation size is selected on a nanometre scale and other parameters in the nanoscale ISSR design are studied. A virtual optical experiment is conducted to use the designed nanoscale ISSR to measure virtual strains. The simulations show that the ISSR can be potentially extended to nanometre-scale measurement of material deformations.
Chapter 1 introduces the technical background and concepts assumed in the subsequent chapters of ... more Chapter 1 introduces the technical background and concepts assumed in the subsequent chapters of the dissertation. A basic description of ISSR operation and set-up is given. Application of the ISSR to residual stress measurements using incremental-hole drilling is described. Concepts and motivation of Nano-ISSR and Multi-ISSR are introduced. Background is given on digital spatial filtering to separate out individual gauge interference patterns. Chapter 2 details the ISSR method for residual stress measurements, covering: (a) derivation of ISSR residual stress measurement inverse model utilizing both strain and slope, (b) finite element model utilized for calculation of ISSR hole-drilling coefficients, (c) experimental study of ISSR measurement of pure strains/slopes on a thin-plate with hole, (d) experimental measurements of incremental ISSR strains/slopes on a shot-peened Titanium-alloy block, and (e) theory and numerical implementation of Tikhonov regularized residual stress solutions on the Titanium-alloy block. Chapter 3 describes a feasibility study on Nano-ISSR that utilized numerical integration of the Rayleigh-Sommerfeld optical scattering equation to predict the sensitivity and feasibility of ISSR measurements with gauge-lengths at the nanometer scale (-1000 nm). The measurement resolution of the Nano-ISSR was estimated to be 0.00 1% for normal strain and 0.1 nm for in-plane relative displacement based on UV laser illumination with 200 nm wavelength and currently available digital cameras.
Abstract: Exhaust durability is an important measure of quality, which can be predicted using CAE... more Abstract: Exhaust durability is an important measure of quality, which can be predicted using CAE with accurate mount loads. This paper proposes an innovative method to calculate these loads from measured mount accelerations. A Chrysler vehicle was instrumented with ...
Journal of Engineering Materials and Technology, 2003
A new experimental method utilizing the Interferometric Strain/Slope Rosette (ISSR) and increment... more A new experimental method utilizing the Interferometric Strain/Slope Rosette (ISSR) and incremental hole-drilling is applied to measure in-plane residual stresses which vary with depth. For each depth increment, the ISSR measures three relieved strain components and two relieved slopes at point near the hole edge. Adapting the classical Integral Method to the ISSR, and incorporating a Tikhonov regularization scheme, stabilized residual stress solutions are back-calculated from the measured deformations. This paper describes the measurement principle of the ISSR, the derivation and numerical calculation of the ISSR hole-drilling coefficients, and the methodology used to back-calculate and regularize the residual stress solution. A verification test on a thin-plate with a through-hole, and residual stress measurements performed on a shot-peened Titanium-alloy block, are presented and discussed.
Chapter 1 introduces the technical background and concepts assumed in the subsequent chapters of ... more Chapter 1 introduces the technical background and concepts assumed in the subsequent chapters of the dissertation. A basic description of ISSR operation and set-up is given. Application of the ISSR to residual stress measurements using incremental-hole drilling is described. Concepts and motivation of Nano-ISSR and Multi-ISSR are introduced. Background is given on digital spatial filtering to separate out individual gauge interference patterns. Chapter 2 details the ISSR method for residual stress measurements, covering: (a) derivation of ISSR residual stress measurement inverse model utilizing both strain and slope, (b) finite element model utilized for calculation of ISSR hole-drilling coefficients, (c) experimental study of ISSR measurement of pure strains/slopes on a thin-plate with hole, (d) experimental measurements of incremental ISSR strains/slopes on a shot-peened Titanium-alloy block, and (e) theory and numerical implementation of Tikhonov regularized residual stress solut...
This paper describes a simple damage model for fatigue life predictions of welded joints under no... more This paper describes a simple damage model for fatigue life predictions of welded joints under nonproportional, constant, and variable amplitude loading histories. This model, an extension of Sonsino’s effective equivalent stress amplitude method, consists of four material parameters accounting for the severity of nonproportional loading paths, the material’s susceptibility to nonproportional hardening, the material’s fatigue life under shear versus normal
This paper describes a simple damage model for fatigue life predictions of welded joints under no... more This paper describes a simple damage model for fatigue life predictions of welded joints under nonproportional, constant, and variable amplitude loading histories. This model, an extension of Sonsino’s effective equivalent stress amplitude method, consists of four material parameters accounting for the severity of nonproportional loading paths, the material’s susceptibility to nonproportional hardening, the material’s fatigue life under shear versus normal
The Journal of Strain Analysis for Engineering Design, 2008
The laser-based interferometric strain—slope rosette (ISSR) has been used to measure principal st... more The laser-based interferometric strain—slope rosette (ISSR) has been used to measure principal strains and stresses on material surfaces. In this paper, optical theory models and computer programs are developed to simulate the optical diffraction and interference of the ISSR. The simulation results compare with the experimental results. Then the feasibility of extending the ISSR into a nanoscale rosette is studied. The indentation size is selected on a nanometre scale and other parameters in the nanoscale ISSR design are studied. A virtual optical experiment is conducted to use the designed nanoscale ISSR to measure virtual strains. The simulations show that the ISSR can be potentially extended to nanometre-scale measurement of material deformations.
Chapter 1 introduces the technical background and concepts assumed in the subsequent chapters of ... more Chapter 1 introduces the technical background and concepts assumed in the subsequent chapters of the dissertation. A basic description of ISSR operation and set-up is given. Application of the ISSR to residual stress measurements using incremental-hole drilling is described. Concepts and motivation of Nano-ISSR and Multi-ISSR are introduced. Background is given on digital spatial filtering to separate out individual gauge interference patterns. Chapter 2 details the ISSR method for residual stress measurements, covering: (a) derivation of ISSR residual stress measurement inverse model utilizing both strain and slope, (b) finite element model utilized for calculation of ISSR hole-drilling coefficients, (c) experimental study of ISSR measurement of pure strains/slopes on a thin-plate with hole, (d) experimental measurements of incremental ISSR strains/slopes on a shot-peened Titanium-alloy block, and (e) theory and numerical implementation of Tikhonov regularized residual stress solutions on the Titanium-alloy block. Chapter 3 describes a feasibility study on Nano-ISSR that utilized numerical integration of the Rayleigh-Sommerfeld optical scattering equation to predict the sensitivity and feasibility of ISSR measurements with gauge-lengths at the nanometer scale (-1000 nm). The measurement resolution of the Nano-ISSR was estimated to be 0.00 1% for normal strain and 0.1 nm for in-plane relative displacement based on UV laser illumination with 200 nm wavelength and currently available digital cameras.
Abstract: Exhaust durability is an important measure of quality, which can be predicted using CAE... more Abstract: Exhaust durability is an important measure of quality, which can be predicted using CAE with accurate mount loads. This paper proposes an innovative method to calculate these loads from measured mount accelerations. A Chrysler vehicle was instrumented with ...
Journal of Engineering Materials and Technology, 2003
A new experimental method utilizing the Interferometric Strain/Slope Rosette (ISSR) and increment... more A new experimental method utilizing the Interferometric Strain/Slope Rosette (ISSR) and incremental hole-drilling is applied to measure in-plane residual stresses which vary with depth. For each depth increment, the ISSR measures three relieved strain components and two relieved slopes at point near the hole edge. Adapting the classical Integral Method to the ISSR, and incorporating a Tikhonov regularization scheme, stabilized residual stress solutions are back-calculated from the measured deformations. This paper describes the measurement principle of the ISSR, the derivation and numerical calculation of the ISSR hole-drilling coefficients, and the methodology used to back-calculate and regularize the residual stress solution. A verification test on a thin-plate with a through-hole, and residual stress measurements performed on a shot-peened Titanium-alloy block, are presented and discussed.
Chapter 1 introduces the technical background and concepts assumed in the subsequent chapters of ... more Chapter 1 introduces the technical background and concepts assumed in the subsequent chapters of the dissertation. A basic description of ISSR operation and set-up is given. Application of the ISSR to residual stress measurements using incremental-hole drilling is described. Concepts and motivation of Nano-ISSR and Multi-ISSR are introduced. Background is given on digital spatial filtering to separate out individual gauge interference patterns. Chapter 2 details the ISSR method for residual stress measurements, covering: (a) derivation of ISSR residual stress measurement inverse model utilizing both strain and slope, (b) finite element model utilized for calculation of ISSR hole-drilling coefficients, (c) experimental study of ISSR measurement of pure strains/slopes on a thin-plate with hole, (d) experimental measurements of incremental ISSR strains/slopes on a shot-peened Titanium-alloy block, and (e) theory and numerical implementation of Tikhonov regularized residual stress solut...
This paper describes a simple damage model for fatigue life predictions of welded joints under no... more This paper describes a simple damage model for fatigue life predictions of welded joints under nonproportional, constant, and variable amplitude loading histories. This model, an extension of Sonsino’s effective equivalent stress amplitude method, consists of four material parameters accounting for the severity of nonproportional loading paths, the material’s susceptibility to nonproportional hardening, the material’s fatigue life under shear versus normal
This paper describes a simple damage model for fatigue life predictions of welded joints under no... more This paper describes a simple damage model for fatigue life predictions of welded joints under nonproportional, constant, and variable amplitude loading histories. This model, an extension of Sonsino’s effective equivalent stress amplitude method, consists of four material parameters accounting for the severity of nonproportional loading paths, the material’s susceptibility to nonproportional hardening, the material’s fatigue life under shear versus normal
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