scholarly journals Mechanical response of inelastic constitutive equation with non-coaxiality based on anisotropy and tangential stress effect for soils

2002 ◽  
Vol 5 ◽  
pp. 401-409
Author(s):  
Seiichiro Tsutsumi ◽  
Koichi Hashiguchi ◽  
Masaya Sugimoto ◽  
Kiyohiro Ikeda ◽  
Yuki Yamakawa
Keyword(s):  
Constitutive Equation ◽  
Tangential Stress ◽  
Mechanical Response ◽  
Stress Effect

Response of harmonic sources in couple stress thermoelastic medium with state space approach

2014 ◽  
Vol 10 (3) ◽  
pp. 449-471
Author(s):  
Rajneesh Kumar ◽  
Krishan Kumar ◽  
Ravindra Chandra Nautiyal
Keyword(s):  
Normal Stress ◽  
Tangential Stress ◽  
Couple Stress ◽  
Wave Number ◽  
Stress Effect ◽  
State Space Approach ◽  
Content Type ◽  
Stress Components ◽  
Circular Frequency ◽  
Space Approach

Purpose – The purpose of this paper is to investigate the two-dimensional problem in couple stress thermoelastic medium for a half space is established and state space approach has been applied to solve the problem. Design/methodology/approach – Normal mode analysis is used to obtain the exact expressions for normal stress, tangential stress and couple stress. Numerical calculation is prepared for these quantities and depicted graphically for a special model. Findings – The expressions for normal stress, tangential stress and couple stress are obtained numerically and depicted graphically to see the couple stress effect. Originality/value – It is found that couple stress effect decrease the value of normal stress components for circular frequency equal to 0.5 for small values of the wave number and then increases whereas the values of normal stress components decrease first and then increase monotonically for circular frequency equal to 0.1 when the force is applied in normal direction and the values of tangential stress components and couple stress components decrease for all values of wave number. But the values for normal stress components, tangential stress components and couple stress components increase when the force is applied in tangential direction.

scholarly journals Modeling the initial mechanical response and yielding behavior of gelled crude oil

Open Physics ◽  
2018 ◽  
Vol 16 (1) ◽  
pp. 292-301 ◽  
Author(s):  
Chen Lei ◽  
Liu Gang ◽  
Lu Xingguo ◽  
Xu Minghai ◽  
Tang Yuannan
Keyword(s):  
Shear Stress ◽  
Constitutive Equation ◽  
Crude Oil ◽  
Shear Strain ◽  
Mechanical Response ◽  
Shear Rates ◽  
Mechanical Analog ◽  
Constant Shear ◽  
Jeffreys Model ◽  
Yielding Behavior

Abstract The initial mechanical response and yielding behavior of gelled crude oil under constant shear rate conditions were investigated. By putting the Maxwell mechanical analog and a special dashpot in parallel, a quasi-Jeffreys model was obtained. The kinetic equation of the structural parameter in the Houska model was simplified reasonably so that a simplified constitutive equation of the special dashpot was expressed. By introducing a damage factor into the constitutive equation of the special dashpot and the Maxwell mechanical analog, we established a constitutive equation of the quasi-Jeffreys model. Rheological tests of gelled crude oil were conducted by imposing constant shear rates and the relationship between the shear stress and shear strain under different shear rates was plotted. It is found that the constitutive equation can fit the experimental data well under a wide range of shear rates. Based on the fitted parameters in the quasi-Jeffreys model, the shear stress changing rules of the Maxwell mechanical analog and the special dashpot were calculated and analyzed. It is found that the critical yield strain and the corresponding shear strain where shear stress of the Maxwell analog is the maximum change slightly under different shear rates. And then a critical damage softening strain which is irrelevant to the shearing conditions was put forward to describe the yielding behavior of gelled crude oil.

Microstructural Evolution in Void Coalescence Induced by Plate-Impact Loading in Ultrapure Aluminum

2010 ◽  
Vol 160-162 ◽  
pp. 434-439 ◽  
Author(s):  
Duan Fan ◽  
Mei Lan Qi
Keyword(s):  
Impact Loading ◽  
Mechanical Response ◽  
Void Nucleation ◽  
Early Stage ◽  
Tensile Fracture ◽  
Void Coalescence ◽  
Stress Effect ◽  
Plate Impact ◽  
Transmission Electron ◽  
Evolution Of Microstructure

The evolution of microstructure and the mechanical response of ultrapure aluminum subjected to plastic deformation using plate-impact loading was investigated. For the High Purity Aluminum (99.999%), disk sample was shock impacted by a light gun. Observations by transmission electron microscopy reveal that the inside of the early voids consists of nanometer aluminum; it is proposed that they are the result of recrystallization occurring during localization. And some texture may come from the high temperature annealing the secondary grain crystallization behavior and crystallization when the tensile stress effect. This discovery is helpful to the study on the mechanism during the early stage of void nucleation and growth which produced by tensile fracture.

On the Elastic Behavior of Scission Materials

2005 ◽  
Vol 10 (1) ◽  
pp. 63-88 ◽  
Author(s):  
Markus Zimmermann ◽  
Alan Wineman
Keyword(s):  
Constitutive Equation ◽  
Mechanical Response ◽  
Elastic Behavior ◽  
Cross Linking ◽  
Deformation History ◽  
Stability Behavior ◽  
Strain Energy Density Function ◽  
New Material ◽  
Macromolecular Network ◽  
The Stability

Constitutive equations have recently been developed which account for changes in the mechanical response of an elastomer due to changes in its macromolecular structure. The changes consist of scission of macromolecular network junctions, recoiling of macromolecules and their subsequent cross linking to form new networks with new stress-free reference configurations. This work discusses changes caused by large deformations. For each deformation history, there is a range of deformations in which the microstructure is fixed, with no further scission or cross linking. The elastomer has a modified elastic behavior and a new stress-free reference configuration. The constitutive equation for this post-scission elastic range is developed. Two subclasses of this constitutive equation are defined: Mooney-Rivlin based and neo-Hookean based scission materials. The strain energy density function for each subclass is derived. It is shown how the new material symmetry is determined from the preceding deformation history and the scission and cross linking processes. The effect of scission on the stability behavior of a neo-Hookean based scission material is discussed and a cube under triaxial load is considered.

scholarly journals The Extended Elastoplastic Constitutive Equation with Tangential Stress Rate Effect

10.5109/24209 ◽  
1997 ◽  
Vol 42 (1/2) ◽  
pp. 225-235
Author(s):  
Koichi Hashiguchi ◽  
Takafumi Okayasu ◽  
Seiichiro Tsutsumi
Keyword(s):  
Constitutive Equation ◽  
Tangential Stress ◽  
Rate Effect ◽  
Stress Rate

Comparison of Substructures Between Uniaxial and Biaxial Deformation in 1100-0 Aluminum

1981 ◽  
Vol 39 ◽  
pp. 52-53
Author(s):  
D. L. Rohr ◽  
S. S. Hecker
Keyword(s):  
Plastic Strain ◽  
Cell Walls ◽  
Room Temperature ◽  
Mechanical Response ◽  
Biaxial Tension ◽  
Initial Deformation ◽  
Uniaxial Deformation ◽  
Biaxial Deformation ◽  
Stress States ◽  
Comprehensive Study

As part of a comprehensive study of microstructural and mechanical response of metals to uniaxial and biaxial deformations, the development of substructure in 1100 A1 has been studied over a range of plastic strain for two stress states.Specimens of 1100 aluminum annealed at 350 C were tested in uniaxial (UT) and balanced biaxial tension (BBT) at room temperature to different strain levels. The biaxial specimens were produced by the in-plane punch stretching technique. Areas of known strain levels were prepared for TEM by lapping followed by jet electropolishing. All specimens were examined in a JEOL 200B run at 150 and 200 kV within 24 to 36 hours after testing.The development of the substructure with deformation is shown in Fig. 1 for both stress states. Initial deformation produces dislocation tangles, which form cell walls by 10% uniaxial deformation, and start to recover to form subgrains by 25%. The results of several hundred measurements of cell/subgrain sizes by a linear intercept technique are presented in Table I.

Construction of plastic contact deformation maps on ceramics: a case study on aluminum nitride

1996 ◽  
Vol 54 ◽  
pp. 636-637
Author(s):  
D. L. Callahan
Keyword(s):  
Plastic Deformation ◽  
Aluminum Nitride ◽  
Mechanical Response ◽  
Three Dimensional ◽  
Bright Field Image ◽  
Perfectly Plastic ◽  
Contrast Analysis ◽  
Deformation Patterns

Modern polishing, precision machining and microindentation techniques allow the processing and mechanical characterization of ceramics at nanometric scales and within entirely plastic deformation regimes. The mechanical response of most ceramics to such highly constrained contact is not predictable from macroscopic properties and the microstructural deformation patterns have proven difficult to characterize by the application of any individual technique. In this study, TEM techniques of contrast analysis and CBED are combined with stereographic analysis to construct a three-dimensional microstructure deformation map of the surface of a perfectly plastic microindentation on macroscopically brittle aluminum nitride.The bright field image in Figure 1 shows a lg Vickers microindentation contained within a single AlN grain far from any boundaries. High densities of dislocations are evident, particularly near facet edges but are not individually resolvable. The prominent bend contours also indicate the severity of plastic deformation. Figure 2 is a selected area diffraction pattern covering the entire indentation area.

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