residual shear stress
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Author(s):  
Quanshun Luo

AbstractX-ray diffraction has been widely used in measuring surface residual stresses. A drawback of the conventional d ~ sin2ψ method is the increased uncertainty arising from sin2ψ splitting when a significant residual shear stress co-exists with a residual normal stress. In particular, the conventional method can only be applied to measure the residual normal stress while leaving the residual shear stress unknown. In this paper, we propose a new approach to make simultaneous measurement of both residual normal and shear stresses. Theoretical development of the new approach is described in detail, which includes two linear regressions, $$\frac{{d}_{\psi }+ {d}_{-\psi }}{2}$$ d ψ + d - ψ 2 ~sin2ψ and {dψ-d-ψ} ~ sin(2ψ), to determine the residual normal and shear stresses separately. Several samples were employed to demonstrate the new method, including turning-machined and grinding-machined cylindrical bars of a high strength steel as well as a flat sample of magnetron sputtered TiN coating. The machined samples were determined to have residual compressive normal stresses at both the axial and hoop directions as well as various scales of residual shear stresses. The TiN coating showed a high scale of residual compressive (normal) stress whereas the measured residual shear stress was extremely low. The new method showed significantly increased precision as compared to the conventional d ~ sin2ψ method.


Author(s):  
Ravi Butola ◽  
Ravi Pratap Singh ◽  
Naman Choudhary ◽  
K. K. S. Mer ◽  
Jitendra Bhaskar ◽  
...  

In the present research, measurement of residual stress induced during turning and threading operations for the fabrication of two types of pin profiled friction stir processing/welding (FSP/FSW) tools, i.e. cylindrical profiled pin tool and cylindrical threaded profiled pin tool, is being dealt with. Workpiece was chosen to be H13 tool steel with a diameter of 22[Formula: see text]mm and 110[Formula: see text]mm length. Turning and threading was done on CNC machine tools using CNMG 12404-THM uncoated tungsten carbide cutting tool. For residual stress measurement of the workpieces, an XRD-based Pulsetec[Formula: see text]-X360n portable residual stress analyzer setup was used. The experimental results show that the cylindrical pin profile tool had a compressive residual stress of [Formula: see text][Formula: see text]MPa and compressive residual shear stress of [Formula: see text][Formula: see text]MPa, while the cylindrical threaded pin profile tool had a compressive residual stress of [Formula: see text][Formula: see text]MPa (51.8% more) and compressive residual shear stress of [Formula: see text][Formula: see text]MPa (40% less). It has been concluded that due to threading operation on the cylindrical threaded pin profile, the value of residual stress is more in it, and since the stress is compressive in nature, it would have a better positive impact while doing FSP/FSW than that of the cylindrical profiled pin tool.


Materials ◽  
2021 ◽  
Vol 14 (1) ◽  
pp. 229
Author(s):  
Sueng-Won Jeong ◽  
Kabuyaya Kighuta ◽  
Dong-Eun Lee ◽  
Sung-Sik Park

The shear and particle crushing characteristics of the failure plane (or shear surface) in catastrophic mass movements are examined with a ring shear apparatus, which is generally employed owing to its suitability for large deformations. Based on results of previous experiments on waste materials from abandoned mine deposits, we employed a simple numerical model based on ring shear testing using the particle flow code (PFC2D). We examined drainage, normal stress, and shear velocity dependent shear characteristics of landslide materials. For shear velocities of 0.1 and 100 mm/s and normal stress (NS) of 25 kPa, the numerical results are in good agreement with those obtained from experimental results. The difference between the experimental and numerical results of the residual shear stress was approximately 0.4 kPa for NS equal to 25 kPa and 0.9 kPa for NS equal to 100 kPa for both drained and undrained condition. In addition, we examined particle crushing effect during shearing using the frictional work concept in PFC. We calculated the work done by friction at both peak and residual shear stresses, and then used the results as crushing criteria in the numerical analysis. The frictional work at peak and the residual shear stresses was ranged from 303 kPa·s to 2579 kPa·s for given drainage and normal stress conditions. These results showed that clump particles were partially crushed at peak shear stress, and further particle crushing with respect to the production of finer in shearing was recorded at residual shear stress at the shearing plane.


2016 ◽  
Vol 113 (35) ◽  
pp. 9745-9750 ◽  
Author(s):  
Carl P. Goodrich ◽  
Andrea J. Liu ◽  
James P. Sethna

We propose a Widom-like scaling ansatz for the critical jamming transition. Our ansatz for the elastic energy shows that the scaling of the energy, compressive strain, shear strain, system size, pressure, shear stress, bulk modulus, and shear modulus are all related to each other via scaling relations, with only three independent scaling exponents. We extract the values of these exponents from already known numerical or theoretical results, and we numerically verify the resulting predictions of the scaling theory for the energy and residual shear stress. We also derive a scaling relation between pressure and residual shear stress that yields insight into why the shear and bulk moduli scale differently. Our theory shows that the jamming transition exhibits an emergent scale invariance, setting the stage for the potential development of a renormalization group theory for jamming.


2016 ◽  
Vol 14 (2) ◽  
pp. 159 ◽  
Author(s):  
Adrian Kraft ◽  
Roman Pohrt

We investigate the tangential contact problem of a spherical indenter at constant normal force. When the indenter is subjected to tangential movement, frictional shear stresses arise at the interface and do not vanish when it is moved backwards. We study the evolution of shear stress when the indenter is moved back and forth at falling amplitude. The method of dimensionality reduction (MDR) is employed for obtaining the distribution of stick and slip zones as well as external forces and the final stress distribution. We find that the shear stress decreases. For the special case of linearly falling amplitude of the movement, we observe uniform peaks in the shear stress. The absolute value of the shear stress peaks is reduced best for a high number of back-and-forth-movements with slowly decreasing amplitude.


2014 ◽  
Vol 445 (1-3) ◽  
pp. 200-208 ◽  
Author(s):  
R. Rakesh ◽  
D. Kohli ◽  
V.P. Sinha ◽  
G.J. Prasad ◽  
I. Samajdar

1996 ◽  
Vol 34 (7) ◽  
pp. 1101-1106 ◽  
Author(s):  
Y. Calik ◽  
J.T. Evans ◽  
B.A. Shaw

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