Structural kinetics constitutive models for characterizing the time-dependent rheologic behaviors of fresh cement paste

2021 ◽  
Vol 276 ◽  
pp. 122175
Author(s):  
Dafu Wang ◽  
Yunsheng Zhang ◽  
Jia Xiao ◽  
Tingjie Huang ◽  
Meng Wu ◽  
...  
2021 ◽  
pp. 13-40
Author(s):  
Gianluca Ranzi ◽  
Giovanni Di Luzio ◽  
Massimiliano Bocciarelli ◽  
Graziano Leoni ◽  
Ahmet Abdullah Dönmez ◽  
...  

<p>This chapter provides an introduction to the constitutive models commonly specified in design guidelines to describe the time-dependent behaviour of concrete and that can be used for the time-dependent analysis of composite structures. These formulations range from the simplest algebraic methods, such as the Effective Modulus Method that is widely recommended in design guidelines, to more sophisticated approaches that can account for creep and shrinkage effects in advanced modelling. The last part of the chapter provides a brief overview of multi-physics modelling that could be useful in predicting the concrete time-dependent response for composite construction.</p>


Author(s):  
Krishna Tunga ◽  
James Pyland ◽  
Raghuram V. Pucha ◽  
Suresh K. Sitaraman

Various constitutive and fatigue-life predictive models for lead-tin solders in SBGA (Super Ball Grid Array) packages are studied and compared with the results from experimental data. Two solder compositions, 62Sn/36Pb/2Ag and 63Sn/37Pb are studied in this work. The fatigue life of 62Sn/36Pb/2Ag solder is studied using different constitutive models that take into consideration both the time-independent and time-dependent behavior of the solder. The fatigue life of 62Sn/36Pb/2Ag solder is predicted using an energy-based predictive model and compared with the experimental data. The choice of various predictive models on the solder joint life is studied using 63Sn/37Pb solder. Various predictive models, available in the literature, for eutectic and near eutectic solder compositions are studied to predict the fatigue life. Guidelines are provided for selecting constitutive and predictive models with appropriate damage metrics.


2012 ◽  
Vol 40 (5) ◽  
pp. 20120042 ◽  
Author(s):  
Wei Chen ◽  
Zhonghe Shui ◽  
Jianfeng Fan

2013 ◽  
Vol 20 (3) ◽  
pp. 285-292 ◽  
Author(s):  
Bahri Ersoy ◽  
Sedef Dikmen ◽  
Tayfun Uygunoğlu ◽  
Mehmet Galip İçduygu ◽  
Taner Kavas ◽  
...  

AbstractThe measurement of zeta potential (ZP) has important applications in a wide range of industries including ceramics, pharmaceuticals, medicine, mineral processing, electronics, cement industry and water treatment. It provides new information on cement hydration, gel structure formation and the effects of chemical and mineral admixtures. In this study, ZP and pH measurements of Portland cement suspension prepared at wt% 1 cement/water ratio in the presence of four different types of waters, i.e., pure water, tap water, and salted (NaCl and CaCl2) water, were carried out depending on the time. Also, vicat tests of Portland cement pastes prepared at a water-to-cement ratio of 0.34 were performed. After the vicat tests, X-ray diffraction analysis and scanning electron microscopy investigations were performed on the samples. The most important result obtained from this study is that setting time and time-dependent ZP values of Portland cement paste have different values depending on the used mixing water type. Among the water types, water with CaCl2 gives the lowest ZP as absolute value, so this leads to minimum initial and final setting times for the cement paste prepared with this type of water.


2011 ◽  
Vol 84 (3) ◽  
pp. 296-324 ◽  
Author(s):  
Aparajita Bhattacharya ◽  
Grigori A. Medvedev ◽  
James M. Caruthers

Abstract An extensive set of time-dependent mechanical data was obtained for several filled SBR elastomers, including Mullins experiments, cyclic loading experiments, and stress relaxation. These comprehensive data enable critical evaluation of three classes of constitutive models. Viscoelastic models can naturally describe the hysteresis upon loading/reloading, but are unable to capture the large change in tangent modulus between the initial loading and the modulus just as the specimen is being unloaded. Elastic-damage models can capture the large change in tangent modulus just prior versus subsequent to unloading of a virgin sample, but can only parameterize the hysteresis on cyclic loading and are unable to predict strain rate effects and stress relaxation. A viscoelastic-damage model can predict the large change in tangent modulus upon reversal of the strain, hysteresis, strain rate effects, and stress relaxation; however, viscoelastic-damage models are unable to simultaneously predict the modest amount of hysteresis observed in cyclic experiments and the large amount of stress relaxation observed after loading to large deformations. The analysis indicates that constitutive models that include different deformation mechanics than the traditional elastic, viscoelastic, and damage processes will be needed to describe the full range of mechanical behavior exhibited by carbon black filled elastomers.


2009 ◽  
Vol 13 (2) ◽  
pp. 199-206 ◽  
Author(s):  
F. J. Rubio-Hernández ◽  
J. F. Velázquez-Navarro ◽  
F. J. Galindo-Rosales

1990 ◽  
Vol 43 (5S) ◽  
pp. S338-S344 ◽  
Author(s):  
U. S. Lindholm

In this paper the author reviews experimental data which is felt to be illustrative of time-dependent, high temperature deformation of metals and, therefore, instructive for the development of constitutive models. Issues addressed are the interrelation between time (strain rate) and temperature, the development of evolutionary equations for both isotropic and directional hardening and recovery, and the orientation of the inelastic strain rate with respect to stress during nonproportional loading.


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