Reflection of a plane-polarized wave from a free surface in a strain-hardening elastic-plastic medium

It has previously been suggested that the reduction in cutting forces obtained by the presence of fluids such as CCl4 on the backface or free surface of the forming chip was due to diffusion of the fluid into the body of the chip in the region of the shear zone. In the present work, experiments with carbon tetrachloride tagged with carbon-14 and with carbon tetrachloride tagged with chlorine-36 were performed with the object of assessing the extent of diffusion of lubricants into the chip when present on the free surface only. The results obtained disprove former hypotheses and suggest that the reduced cutting force is due solely to chemical reaction at the surface of the chip. Confirmation of the sensitivity of the surface of the deforming shear zone to change in surface condition was obtained by removing metal from this region by an electropolishing technique during slow speed cutting. By varying the electropolishing conditions increased or decreased cutting forces could be obtained. It is proposed that the result both of chemical reaction at the surface and of surface removal is to reduce the strain-hardening rate of the metal undergoing shear by reducing the surface barrier to the flow of dislocations out of the metal. The association of the surface reaction of carbon tetrachloride with a change in the strain-hardening characteristics of the metal in the shear zone leads to a classification of the backface phenomenon as a Rehbinder effect and enables this effect to be more closely defined than was hitherto possible. Evidence is also presented which indicates that the backface effect does not contribute to the reduction in cutting forces during rakeface lubrication and is therefore unimportant in practice where flood lubrication of the cutting region invariably occurs.

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Relationship Between Rockwell C Hardness and Inelastic Material Constants

Journal of Engineering Materials and Technology ◽

10.1115/1.1446863 ◽

2002 ◽

Vol 124 (2) ◽

pp. 179-184 ◽

Cited By ~ 3

Author(s):

Akihiko Hirano ◽

Masao Sakane ◽

Naomi Hamada

Keyword(s):

Finite Element ◽

Friction Coefficient ◽

Strain Hardening ◽

Yield Stress ◽

Plastic Material ◽

Stress And Strain ◽

Material Constants ◽

Elastic Plastic ◽

Elastic Plastic Material ◽

Hardening Coefficient

This paper describes the relationship between Rockwell C hardness and elastic-plastic material constants by using finite element analyses. Finite element Rockwell C hardness analyses were carried out to study the effects of friction coefficient and elastic-plastic material constants on the hardness. The friction coefficient and Young’s modulus had no influence on the hardness but the inelastic materials constants, yield stress, and strain hardening coefficient and exponent, had a significant influence on the hardness. A new equation for predicting the hardness was proposed as a function of yield stress and strain hardening coefficient and exponent. The equation evaluated the hardness within a ±5% difference for all the finite element and experimental results. The critical thickness of specimen and critical distance from specimen edge in the hardness testing was also discussed in connection with JIS and ISO standards.

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An Approximate Model for an Elastic-Plastic Pipe Element Under Combined Loading

Journal of Pressure Vessel Technology ◽

10.1115/1.3454248 ◽

1975 ◽

Vol 97 (1) ◽

pp. 22-28 ◽

Cited By ~ 4

Author(s):

L. D. Larson ◽

W. F. Stokey ◽

W. E. Franzen

Keyword(s):

Strain Hardening ◽

Axial Load ◽

Analytical Approach ◽

Limit Load ◽

Approximate Model ◽

Experimental Results ◽

Combined Loading ◽

Elastic Plastic ◽

Plastic Pipe ◽

Plastic Analysis

An approximate model for the elastic-plastic analysis of a pipe element under combined loading is developed. The model is obtained by generalizing a limit load solution for combined pressure, bending, torsion and axial load to include strain hardening. For various combinations of loading of tubes, curvatures and twist angles are predicted and compared with experimental results and those predicted by a more rigorous analytical approach. The comparison shows that good results are obtained from the approximate model.

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