An Energy Approach to the Mechanics of Discontinuous Chip Formation

1964 ◽  
Vol 86 (2) ◽  
pp. 157-162 ◽  
Author(s):  
W. K. Luk ◽  
R. C. Brewer

After briefly reviewing previous work in this field, the authors propose that rupture of the chip work contact (to give a discontinuous chip) is governed by a limiting shear strain energy condition. Assuming that shear stress and strain at rupture are dependent on the compressive normal stress, a criterion for the direction of the rupture plane is deduced. Using some results given by Field and Merchant, the authors then compare their calculated direction of rupture with that experimentally observed. Some indication that the agreement is not entirely fortuitous is afforded by checking the calculated shear strain energy at fracture with that calculated from force and chip measurements.

Author(s):  
R. O. Davis ◽  
J. B. Berrill

The Port Island, Kobe downhole records from the Hyogo-ken Nanbu earthquake are analysed to obtain approximate histories of shear stress, shear strain and dissipated energy at a range of depths. Our calculation method relies on measured accelerations in the horizontal plane to produce horizontal components of shear stress and strain using instantaneous modal superposition. A simple dissipated energy-dynamic pore pressure relationship is used to model the development of pore pressure leading to liquefaction. The results show a rapidly developing zone of liquefaction which initiates at a depth of roughly 15 metres in the Port Island reclaimed soils.


2011 ◽  
Vol 197-198 ◽  
pp. 552-557
Author(s):  
Ming Li

A more exact general analytical formula of preditcting the magnetostrictive coefficient is derived for any aspect ratio based the deflection difference between the x and y directions. The curvatures are found by minimizing the total energy of the system, which taking into account shear strain energy. The in-plane stress distribution including shear stress for short specimen is also given by the ANSYS® finite element package to illustrate the role of shear strain in the deformation of magnetostrictive film-substrate system.


1957 ◽  
Vol 24 (3) ◽  
pp. 464-466
Author(s):  
C. D. Weir

Abstract Using the usually accepted assumption that the strain rate of a material undergoing creep is given by the product of the stress deviator and a function of the shear-strain energy, and assuming constant density, equations are derived for the creep stresses in a thick-walled tube under internal pressure for a generalized form of the shear strain-energy function. It is shown that these reduce to previously published equations on the substitution of a power law stress-strain rate equation. The nonisothermal case is considered also and creep-stress equations are obtained in a similarly generalized form.


2011 ◽  
Vol 16 (1) ◽  
pp. 145-154 ◽  
Author(s):  
Byoung Koo Lee ◽  
Sang Jin Oh ◽  
Tae Eun Lee ◽  
Jung Su Park

2013 ◽  
Vol 353-356 ◽  
pp. 901-904
Author(s):  
Shou Yi Xue

The composition of the energy in the process of material deformation and failure and the relationship between energy and strength were summarized; the features, essences and main problems of the energy release rate theory, the three-shear energy theory and the net shear strain energy density theory were illustrated. It is pointed out that the roles of distortion strain energy, volumetric strain energy and dissipated energy are not identical, especially distortion strain energy and volumetric strain energy must be separately processed. The three-shear energy theory and the net shear strain energy density theory can properly deal with the problems, and also well reflect the intermediate principal stress effect. The above research results can provide references for further discussions.


2008 ◽  
Vol 295 (4) ◽  
pp. H1608-H1614 ◽  
Author(s):  
Frank J. H. Gijsen ◽  
Jolanda J. Wentzel ◽  
Attila Thury ◽  
Frits Mastik ◽  
Johannes A. Schaar ◽  
...  

Once plaques intrude into the lumen, the shear stress they are exposed to alters with hitherto unknown consequences for plaque composition. We investigated the relationship between shear stress and strain, a marker for plaque composition, in human coronary arteries. We imaged 31 plaques in coronary arteries with angiography and intravascular ultrasound. Computational fluid dynamics was used to obtain shear stress. Palpography was applied to measure strain. Each plaque was divided into four regions: upstream, throat, shoulder, and downstream. Average shear stress and strain were determined in each region. Shear stress in the upstream, shoulder, throat, and downstream region was 2.55 ± 0.89, 2.07 ± 0.98, 2.32 ± 1.11, and 0.67 ± 0.35 Pa, respectively. Shear stress in the downstream region was significantly lower. Strain in the downstream region was also significantly lower than the values in the other regions (0.23 ± 0.08% vs. 0.48 ± 0.15%, 0.43 ± 0.17%, and 0.47 ± 0.12%, for the upstream, shoulder, and throat regions, respectively). Pooling all regions, dividing shear stress per plaque into tertiles, and computing average strain showed a positive correlation; for low, medium, and high shear stress, strain was 0.23 ± 0.10%, 0.40 ± 0.15%, and 0.60 ± 0.18%, respectively. Low strain colocalizes with low shear stress downstream of plaques. Higher strain can be found in all other plaque regions, with the highest strain found in regions exposed to the highest shear stresses. This indicates that high shear stress might destabilize plaques, which could lead to plaque rupture.


2013 ◽  
Vol 423-426 ◽  
pp. 1644-1647
Author(s):  
Shou Yi Xue

The net shear strain energy density strength theory was systematically explained. Firstly, the composition of elastic strain energy and the roles of their own were analyzed, and it is pointed out that the distortion strain energy is the energy driving failure and the volumetric strain energy can help improve the material strength. Therefore, ultimate energy driving material damage should be the shear strain energy after deducting the friction effect, namely the net shear strain energy, which indicates rationality of the assumption adopted by the net shear strain energy strength theory. Secondly, the empirical laws of geomaterial strength were summarized and explained by using the net shear strain energy theory, which verifies the new theory is appropriate.


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