Increasing the capacity of camshafts in automobile engines by plastic strain hardening of the surface

1979 ◽  
Vol 15 (9) ◽  
pp. 832-835
Author(s):  
I. V. Kudryavtsev ◽  
�. Ya. Filatov ◽  
V. E. Pavlovskii ◽  
K. M. Pugachevskii
Keyword(s):  
Plastic Strain ◽  
Strain Hardening ◽  
Automobile Engines

The Effect of Plastic Deformation on the Thermoelastic Constant and the Potential to Evaluate Residual Stress

2011 ◽  
Vol 70 ◽  
pp. 458-463 ◽  
Author(s):  
A. F. Robinson ◽  
Janice M. Dulieu-Barton ◽  
S. Quinn ◽  
R. L. Burguete
Keyword(s):  
Residual Stress ◽  
Plastic Deformation ◽  
Plastic Strain ◽  
Strain Hardening ◽  
Thermoelastic Stress ◽  
Paint Coating ◽  
Full Field ◽  
Thermoelastic Constant ◽  
Thermoelastic Response ◽  
Measured Change

In some metals it has been shown that the introduction of plastic deformation or strain modifies the thermoelastic constant, K. If it was possible to define the magnitude of the change in thermoelastic constant over a range of plastic strain, then the plastic strain that a material has experienced could be established based on a measured change in the thermoelastic constant. This variation of the thermoelastic constant and the ability to estimate the plastic strain that has been experienced, has potential to form the basis of a novel non-destructive, non-contact, full-field technique for residual stress assessment using thermoelastic stress analysis (TSA). Recent research has suggested that the change in thermoelastic constant is related to the material dislocation that occurs during strain hardening, and thus the change in K for a material that does not strain harden would be significantly less than for a material that does. In the work described in this paper, the change in thermoelastic constant for three materials (316L stainless steel, AA2024 and AA7085) with different strain hardening characteristics is investigated. As the change in thermoelastic response due to plastic strain is small, and metallic specimens require a paint coating for TSA, the effects of the paint coating and other test factors on the thermoelastic response have been considered.

scholarly journals On Computational Modelling Of Strain-Hardening Material Dynamics

2012 ◽  
Vol 11 (5) ◽  
pp. 1525-1546 ◽  
Author(s):  
Philip Barton ◽  
Evgeniy Romenski
Keyword(s):  
Relaxation Time ◽  
Stress Relaxation ◽  
Plastic Strain ◽  
Strain Hardening ◽  
Three Dimensional ◽  
Computational Modelling ◽  
Constitutive Models ◽  
Successful Implementation ◽  
Hardening Material ◽  
Dislocation Mechanics

AbstractIn this paper we show that entropy can be used within a functional for the stress relaxation time of solid materials to parametrise finite viscoplastic strain-hardening deformations. Through doing so the classical empirical recovery of a suitable irreversible scalar measure of work-hardening from the three-dimensional state parameters is avoided. The success of the proposed approach centres on determination of a rate-independent relation between plastic strain and entropy, which is found to be suitably simplistic such to not add any significant complexity to the final model. The result is sufficiently general to be used in combination with existing constitutive models for inelastic deformations parametrised by one-dimensional plastic strain provided the constitutive models are thermodynamically consistent. Here a model for the tangential stress relaxation time based upon established dislocation mechanics theory is calibrated for OFHC copper and subsequently integrated within a two-dimensional moving-mesh scheme. We address some of the numerical challenges that are faced in order to ensure successful implementation of the proposedmodel within a hydrocode. The approach is demonstrated through simulations of flyer-plate and cylinder impacts.

A Characteristic and a Precisely Constitutive Model for Undrained Clay

2020 ◽  
Vol 975 ◽  
pp. 203-207
Author(s):  
Shih Tsung Hsu ◽  
Wen Chi Hu ◽  
Yu Heng Lin ◽  
Zhuo Ling
Keyword(s):  
Shear Strength ◽  
Plastic Strain ◽  
Constitutive Model ◽  
Strain Hardening ◽  
Undrained Shear Strength ◽  
Triaxial Tests ◽  
Stress Strain ◽  
Proposed Model ◽  
Taipei Basin ◽  
Undrained Shear

Constitutive models for soils are usually adopted in numerical method to analyze the behavior of geotechnical structures. This study performs a series of consolidated-undrained triaxial tests to establish the stress-strain curve of clay. A constitutive model that considers continuous strain hardening-softening is proposed based on the results of triaxial tests. Triaxial test results reveal that undrained shear strength linearly increases with an increase in consolidated pressure , the normalized undrained shear strength is about 0.52 not only for this study but also for the other two cases around Taipei Basin. Due to undrained condition, an associated flow rule between plastic strain increment and stress tensor is adopted. As accumulative plastic strain or/and consolidated pressure change, the mobilized undrained shear strength also changes. All parameters needed for the proposed model can be expressed as a function of undrained shear strength Su, The mobilized undrained shear strength for the proposed model during strain hardening-softening can be in term of accumulative plastic strain. This model can calculate the stress-strain curves of clayed soils accurately.

Visco-Elastic-Plastic Constitutive Model for A7N01-T6 Alloy Welding and Analytical Solutions with Finite Element Codes

2013 ◽  
Vol 446-447 ◽  
pp. 284-287
Author(s):  
K.J. Song ◽  
Y.H. Wei ◽  
Z.B. Dong ◽  
K. Fang ◽  
W.J. Zheng ◽  
...  
Keyword(s):  
Finite Element ◽  
Plastic Strain ◽  
Constitutive Model ◽  
Strain Hardening ◽  
Strain Softening ◽  
Great Influence ◽  
Welding Process ◽  
Welding Residual Stress ◽  
Creep Equation ◽  
Maximum Deformation

This paper has established a viscoelasticplastic constitutive model for A7N01T6 alloy welding, which is temperature and deformation history dependent. The model uses elasticmixed hardening plastic and creep equation to describe the strain hardening at low temperatures and strain softening at high temperatures, respectively. Then it is applied for finite element numerical simulation of the welding process. By comparison with the conventional temperature dependent elasticperfectly plastic model, the overall longitudinal residual compressive plastic strain and the maximum deformation of welding sheet are larger. This is because that the plastic strain is mostly produced in high temperature range. Strain softening has great influence on the evolution of plastic strain. The compressive plastic strain during heating is larger than the tensile plastic strain during cooling. Strain hardening effect on welding residual strain and stress is almost negligible. Using the established constitutive model, welding residual stress and strain are in good agreement with the theoretical results.

Correlation between Resilient Modulus and Plastic Deformation for Cohesive Subgrade Soil under Repeated Loading

2008 ◽  
Vol 2053 (1) ◽  
pp. 72-79 ◽  
Author(s):  
Shu-Rong Yang ◽  
Wei-Hsing Huang ◽  
Chi-Chou Liao
Keyword(s):  
Plastic Deformation ◽  
Plastic Strain ◽  
Strain Hardening ◽  
Resilient Modulus ◽  
Cohesive Soil ◽  
Repeated Loading ◽  
Hardening Behavior ◽  
Subgrade Soil ◽  
Stress Levels ◽  
Strain Hardening Behavior

Pavement performance is related to resilient modulus and plastic deformation of pavement materials, which in turn are affected by environmental conditions and traffic loading. A series of triaxial tests was conducted on a residual lateritic soil for 10,000 load repetitions, with some specimens subjected to 100,000 load repetitions, to characterize the behavior of cohesive subgrades under repeated loading, including resilient modulus and plastic deformation. The shakedown concept was used to describe the accumulated plastic deformation and the strain-hardening and softening behavior. Experimental results show that the resilient modulus of cohesive subgrades exhibits strain-hardening behavior under low stress levels. In the meantime, the rate of plastic strain accumulation becomes diminutive. Soil under this condition is in a stable state. Conversely, under high stress levels, cohesive soil tends to soften after a specific number of load applications and accumulates excessive plastic strain and leads to an unstable state. To predict the plastic strain of subgrade soil under repetitive loading, regression models incorporating the strain-hardening behavior for a cohesive soil were used.

Tensile Deformation Behaviors of Ultra-Fine Subgrained Aluminum

2011 ◽  
Vol 683 ◽  
pp. 189-192
Author(s):  
Xiao Jing Xu ◽  
Cheng Cheng ◽  
Yong Luo ◽  
Tao Song ◽  
Zhen Dan Fei
Keyword(s):  
Dislocation Density ◽  
Plastic Strain ◽  
Theoretical Calculation ◽  
Strain Hardening ◽  
High Strain ◽  
Tensile Deformation ◽  
Peak Stress ◽  
Low Dislocation Density ◽  
Deformation Behaviors ◽  
Dislocation Density Increase

Tensile deformation behaviors up to peak stress of the ultra-fine subgrained aluminum (2024Al) with the subgrain sizes of about 250 nm and low dislocation density inside were investigated. The results show that the ultra-fine subgrained aluminum exhibited high strain hardening and large uniform plastic strain (19.3 %), but little post-deformation hardness/dislocation density increases (99.6 HV vs. 100.3 HV and 0.79×1014 m-2 vs. 1.03×1014 m-2, respectively). The theoretical calculation based on Taylor equation demonstrated that the dislocation density increase during the tensile deformation up to peak stress was very enormous (1.64×1015 m-2). These results not only implied that the dislocations involved in the tensile deformation were in large quantities but most of them disappeared upon the unloading of the tensile deformation, but also demonstrated that high strain hardening capacity is not a sufficient factor for ultra-fine subgrained metals to store deformation dislocations leading to post-deformation hardness increases.

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