Investigation of Stress-Strain Constitutive Behavior of Intermetallic Alloys

2017 ◽  
Vol 34 (3) ◽  
pp. 349-361 ◽  
Author(s):  
H. C. Cheng ◽  
H. C. Hu ◽  
R. Y. Hong ◽  
W. H. Chen
Keyword(s):  
Effective Means ◽  
Plastic Property ◽  
Analysis Procedure ◽  
Constitutive Behavior ◽  
High Plasticity ◽  
Stress Strain ◽  
Representative Strain ◽  
Elastoplastic Properties ◽  
Solution Robustness ◽  
Reverse Analysis

AbstractThe study aims to estimate the stress-strain constitutive behavior of intermetallic compounds (IMCs) observed in a solder interconnect from experimental nanoindentation responses through a modified analysis procedure for improved solution robustness based on Cheng and Cheng's and Dao et al.'s models. On the basis of parametric finite element nanoindentation simulation and dimensional analysis together with the concept of representative strain, a set of universal dimensionless functions are established, by which a forward and reverse analysis algorithm are created to predict nanoindentation responses from given elastoplastic properties and vice versa, respectively. The proposed analysis procedure is validated through comparison with the experimental nanoindentation responses and limited literature data. The results show that the proposed analysis procedure is an effective means for plastic property characterization of micro/nanoscale IMCs. The representative strain is found to be 0.056, which differs from the Dao et al.'s and Giannakopoulos and Suresh's estimate. Besides, though generally brittle and hard in nature, the IMCs in a micro/nanoscale thickness show high plasticity, and comprise a yield strength surpassing most typical engineering metals.

Effect of OCR on sampling disturbance of cohesive soils and evaluation of laboratory reconsolidation procedures

2005 ◽  
Vol 42 (2) ◽  
pp. 459-474 ◽  
Author(s):  
Marika Santagata ◽  
John T Germaine
Keyword(s):  
Effective Means ◽  
Triaxial Tests ◽  
Single Element ◽  
Cohesive Soils ◽  
Stress Strain ◽  
Overconsolidation Ratio ◽  
Strain Behavior ◽  
Preconsolidation Pressure ◽  
Strength Behavior ◽  
Undrained Strength

The paper presents the results of an experimental investigation of sampling disturbance in cohesive soils through single-element triaxial tests on resedimented Boston blue clay (RBBC). The first part of the paper discusses the effect of the overconsolidation ratio (OCR) (1–8) of the soil on postdisturbance compression and undrained shear behavior. The results demonstrate that sensitivity to disturbance decreases markedly with OCR. It is also found that for the medium-sensitivity soil tested, the estimate of the preconsolidation pressure is not significantly affected by OCR. The second part of the paper discusses laboratory reconsolidation procedures. For OCR1 RBBC, the recompression method is not effective in recovering the stress–strain behavior of the soil and, for greater disturbance, provides an increasingly unsafe estimate of the strength. For OCR4, provided the reconsolidation path reproduces the path that occurred in the field, this procedure succeeds in recovering the intact stress–strain–strength behavior of the soil. SHANSEP reconsolidation was investigated for normally consolidated RBBC only. For modest levels of disturbance, this is an effective means of evaluating both the stress–strain and the strength behavior of the soil. For greater levels of disturbance, the stress–strain behavior is not fully recovered, but the method continues to provide conservative estimates of the undrained strength.Key words: sampling disturbance, clays, overconsolidation ratio, undrained strength, recompression, SHANSEP.

Determining Representative Stress and Representative Strain in Deriving Indentation Flow Curves Based on Finite Element Analysis

2005 ◽  
Vol 297-300 ◽  
pp. 2152-2157 ◽  
Author(s):  
Eun Chae Jeon ◽  
Min Kyung Baik ◽  
Sung Hoon Kim ◽  
Baik Woo Lee ◽  
Dong Il Kwon
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Indentation Test ◽  
Plastic Property ◽  
Tensile Tests ◽  
Uniaxial Tensile ◽  
Flow Curves ◽  
Element Analysis ◽  
Representative Strain ◽  
Instrumented Indentation Test

A new method [1] to evaluate indentation flow curves using an instrumented indentation test has been applied to many materials for several years. Though the method produces relatively good results compared to uniaxial tensile tests, a few parameters had not been verified by theoretical or numerical methods. In this study, proportional constants of representative strain and representative stress were verified using finite element analysis and proven to be unaffected by the elastic property and strain level. The constants were generally dependent on the plastic property; however, one combination of the constants is independent of all properties. The values of this combination are consistent with early research and produced overlapping indentation flow curves with uniaxial curves.

scholarly journals Stress-strain State of Thick-walled Soil Cylinder with Sand Core and Grillage View of Elastoplastic Properties of the Soil

2014 ◽  
Vol 91 ◽  
pp. 286-291 ◽  
Author(s):  
Zaven G. Ter-Martirosyan ◽  
A.Z. Ter-Martirosyan ◽  
P.V. Strunin ◽  
O.I. Rubcov
Keyword(s):  
Strain State ◽  
Stress Strain ◽  
Stress Strain State ◽  
Sand Core ◽  
Elastoplastic Properties

On radial crack and half-penny crack induced by Vickers indentation

2008 ◽  
Vol 464 (2099) ◽  
pp. 2967-2984 ◽  
Author(s):  
Yuye Tang ◽  
Akio Yonezu ◽  
Nagahisa Ogasawara ◽  
Norimasa Chiba ◽  
Xi Chen
Keyword(s):  
Experimental Data ◽  
Fracture Toughness ◽  
Stress Intensity Factor ◽  
Crack Length ◽  
Radial Crack ◽  
Stress Fields ◽  
Finite Element Analyses ◽  
Vickers Indentation ◽  
Elastoplastic Properties ◽  
Reverse Analysis

Based on the stress fields formed upon Vickers indentation, the radial crack and half-penny crack systems are analysed separately using finite-element analyses. The crack length is correlated with the stress intensity factor (SIF) at the crack front and material elastoplastic properties via explicit relationships, from which a reverse analysis can be carried out such that the critical SIF (fracture toughness) can be readily derived once the crack length is measured. The proposed technique is validated by comparing with experimental data in the literature as well as parallel experiments of Vickers indentation-induced cracking.

Representative Strain of Indentation Analysis

2005 ◽  
Vol 20 (8) ◽  
pp. 2225-2234 ◽  
Author(s):  
Nagahisa Ogasawara ◽  
Norimasa Chiba ◽  
Xi Chen
Keyword(s):  
Mechanical Properties ◽  
Stress State ◽  
Work Hardening ◽  
Biaxial Loading ◽  
Representative Strain ◽  
Indentation Analysis ◽  
Reverse Analysis ◽  
Engineering Materials ◽  
Definition Of ◽  
New Formulation

Indentation analysis based on the concept of representative strain offers an effective way of obtaining mechanical properties, especially work-hardening behavior of metals, from reverse analysis of indentation load–displacement data, and does not require measuring of the projected contact area. The definition of representative strain adopted in previous studies [e.g., Dao et al., Acta Mater.49, 3899 (2001)] has a weak physical basis, and it works only for a limited range in some sense of engineering materials. A new indentation stress-state based formulation of representation is proposed in this study, which is defined as the plastic strain during equi-biaxial loading. Extensive numerical analysis based on the finite element method has shown that with the new formulation of representative strain and representative stress, the critical normalized relationship between load and material parameters is essentially independent of the work-hardening exponent for all engineering materials, and the results also hold for three distinct indenter angles. The new technique is used for four materials with mechanical properties outside the applicable regime of previous studies, and the reverse analysis has validated the present analysis. The new formulation based on indentation stress-state based definition of representative strain has the potential to quickly and effectively measure the mechanical properties of essentially all engineering materials as long as their constitutive behavior can be approximated into a power-law form.

Basalt fiber reinforced porous aggregates-geopolymer based cellular material

2015 ◽  
Vol 08 (01) ◽  
pp. 1550005 ◽  
Author(s):  
Xin Luo ◽  
Jin-Yu Xu ◽  
Weimin Li
Keyword(s):  
Basalt Fiber ◽  
Strain Curve ◽  
Civil Defense ◽  
Cellular Material ◽  
High Plasticity ◽  
Fiber Reinforced ◽  
Stress Strain Curve ◽  
Stress Strain ◽  
Energy Absorbing ◽  
The Ideal

Basalt fiber reinforced porous aggregates-geopolymer based cellular material (BFRPGCM) was prepared. The stress–strain curve has been worked out. The ideal energy-absorbing efficiency has been analyzed and the application prospect has been explored. The results show the following: fiber reinforced cellular material has successively sized pore structures; the stress–strain curve has two stages: elastic stage and yielding plateau stage; the greatest value of the ideal energy-absorbing efficiency of BFRPGCM is 89.11%, which suggests BFRPGCM has excellent energy-absorbing property. Thus, it can be seen that BFRPGCM is easy and simple to make, has high plasticity, low density and excellent energy-absorbing features. So, BFRPGCM is a promising energy-absorbing material used especially in civil defense engineering.

scholarly journals Investigation of the Mechanical Behavior of Polypropylene Fiber-Reinforced Red Clay

2021 ◽  
Vol 11 (22) ◽  
pp. 10521
Author(s):  
Jia Liu ◽  
Xi’an Li ◽  
Gang Li ◽  
Jinli Zhang
Keyword(s):  
Shear Strength ◽  
Polypropylene Fiber ◽  
Strain Curve ◽  
Triaxial Tests ◽  
High Water Content ◽  
Hyperbolic Model ◽  
High Plasticity ◽  
Fiber Reinforced ◽  
Red Clay ◽  
Stress Strain

Red clay is not easy to use as a natural foundation because of its high water content, high plasticity index, large void ratio, and susceptibility to shrinkage and cracking. In this study, consolidated undrained triaxial tests were conducted to examine the mechanical properties of polypropylene fiber-reinforced red clay and to analyze the influence of the fiber content (FC), fiber length (FL), and cell pressure on its shear strength. By performing a regression analysis on the test data, a hyperbolic constitutive model that considers the influence of FC, FL, and cell pressure was established, and a method was developed to estimate the parameters of the model. The findings show that, in contrast with the nonreinforced red clay, the fiber-reinforced red clay had a stress-strain curve characterized by typical strain hardening, with the shear strength increasing with FC, FL and cell pressure. The calculated results of the model coincide with the test results well, confirming that the hyperbolic model could appropriately describe the stress-strain relationship of polypropylene fiber-reinforced red clay and have reference value for the design and construction of fiber-reinforced red clay foundations.

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